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Title: The Garotters
Author: William D. Howells
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FOREWORD
Although successful heavier-than-air flight is less than two decades old,
and successful dirigible propulsion antedates it by a very short period,
the mass of experiment and accomplishment renders any one-volume history of the subject a matter of selection.
In addition
to the restrictions imposed by space limits,
the material
for compilation is fragmentary,
and,
in many cases,
scattered through periodical and other publications.
Hitherto,
there has been no attempt at furnishing a detailed account of how the aeroplane and the dirigible of to-day came
to being,
but each author who has treated the subject has devoted his attention
to some special phase or section.
The principal exception
to this rule--Hildebrandt--wrote in 1906,
and a good many of his statements are inaccurate,
especially
with regard
to heavier-than-air experiment.
Such statements as are made in this work are,
where possible,
given
with acknowledgment
to the authorities on which they rest.
Further acknowledgment is due
to Lieut.-Col.
Lockwood Marsh,
not only
for the section on aeroplane development which he has contributed
to the work,
but also
for his kindly assistance and advice in connection
with the section on aerostation.
The author's thanks are also due
to the Royal Aeronautical Society
for free access
to its valuable library of aeronautical literature,
and
to Mr A.
Vincent Clarke
for permission
to make use of his notes on the development of the aero engine.
In this work is no claim
to originality--it has been a matter mainly of compilation,
and some stories,
notably those of the Wright Brothers and of Santos Dumont,
are better told in the words of the men themselves than any third party could tell them.
The author claims,
however,
that this is the first attempt at recording the facts of development and stating,
as fully as is possible in the compass of a single volume,
how flight and aerostation have evolved.
The time
for a critical history of the subject is not yet.
In the matter of illustrations,
it has been found very difficult
to secure suitable material.
Even the official series of photographs of aeroplanes in the war period is curiously incomplete'
and the methods of censorship during that period prevented any complete series being privately collected.
Omissions in this respect will probably be remedied in future editions of the work,
as fresh material is constantly being located.
E.C.V.
October,
1920.
CONTENTS Part I--THE EVOLUTION OF THE AEROPLANE I.
THE PERIOD OF LEGEND II.
EARLY EXPERIMENTS III.
SIR GEORGE CAYLEY--THOMAS WALKER IV.
THE MIDDLE NINETEENTH CENTURY V.
WENHAM,
LE BRIS,
AND SOME OTHERS VI.
THE AGE OF THE GIANTS VII.
LILIENTHAL AND PILCHER VIII.
AMERICAN GLIDING EXPERIMENTS IX.
NOT PROVEN X.
SAMUEL PIERPOINT LANGLEY XI.
THE WRIGHT BROTHERS XII.
THE FIRST YEARS OF CONQUEST XIII.
FIRST FLIERS IN ENGLAND XIV.
RHEIMS,
AND AFTER XV.
THE CHANNEL CROSSING XVI.
LONDON
to MANCHESTER XVII.
A SUMMARY--TO 1911 XVIII.
A SUMMARY--TO 1914 XIX.
THE WAR PERIOD--I XX.
THE WAR PERIOD--II XXI.
RECONSTRUCTION XXII.
1919-1920 Part II--1903-1920:
PROGRESS IN DESIGN I.
THE BEGINNINGS II.
MULTIPLICITY OF IDEAS III.
PROGRESS ON STANDARDISED LINES IV.
THE WAR PERIOD Part III--AEROSTATICS I.
BEGINNINGS II.
THE FIRST DIRIGIBLES III.
SANTOS-DUMONT IV.
THE MILITARY DIRIGIBLE V.
BRITISH AIRSHIP DESIGN VI.
THE AIRSHIP COMMERCIALLY VII.
KITE BALLOONS PART IV--ENGINE DEVELOPMENT I.
THE VERTICAL TYPE II.
THE VEE TYPE III.
THE RADIAL TYPE IV.
THE ROTARY TYPE V.
THE HORIZONTALLY-OPPOSED ENGINE VI.
THE TWO-STROKE CYCLE ENGINE VII.
ENGINES OF THE WAR PERIOD APPENDICES PART I THE EVOLUTION OF THE AEROPLANE I.
THE PERIOD OF LEGEND The blending of fact and fancy which men call legend reached its fullest and richest expression in the golden age of Greece,
and thus it is
to Greek mythology that one must turn
for the best form of any legend which foreshadows history.
Yet the prevalence of legends regarding flight,
existing in the records of practically every race,
shows that this form of transit was a dream of many peoples--man always wanted
to fly,
and imagined means of flight.
In this age of steel,
a very great part of the inventive genius of man has gone into devices intended
to facilitate transport,
both of men and goods,
and the growth of civilisation is in reality the facilitation of transit,
improvement of the means of communication.
He was a genius who first hoisted a sail on a boat and saved the labour of rowing;
equally,
he who first harnessed ox or dog or horse
to a wheeled vehicle was a genius--and these looked up,
as men have looked up from the earliest days of all,
seeing that the birds had solved the problem of transit far more completely than themselves.
So it must have appeared,
and there is no age in history in which some dreamers have not dreamed of the conquest of the air;
if the caveman had left records,
these would without doubt have showed that he,
too,
dreamed this dream.
His main aim,
probably,
was self-preservation;
when the dinosaur looked round the corner,
the prehistoric bird got out of the way in his usual manner,
and prehistoric manÄ such of him as succeeded in getting out of the way after his fashion--naturally envied the bird,
and concluded that as lord of creation in a doubtful sort of way he ought
to have equal facilities.
He may have tried,
like Simon the Magician,
and other early experimenters,
to improvise those facilities;
assuming that he did,
there is the groundwork of much of the older legend
with regard
to men who flew,
since,
when history began,
legends would be fashioned out of attempts and even the desire
to fly,
these being compounded of some small ingredient of truth and much exaggeration and addition.
In a study of the first beginnings of the art,
it is worth while
to mention even the earliest of the legends and traditions,
for they show the trend of men's minds and the constancy of this dream that has become reality in the twentieth century.
In one of the oldest records of the world,
the Indian classic Mahabarata,
it is stated that
'Krishna's enemies sought the aid of the demons,
who built an aerial chariot
with sides of iron and clad
with wings.
The chariot was driven through the sky till it stood over Dwarakha,
where Krishna's followers dwelt,
and from there it hurled down upon the city missiles that destroyed everything on which they fell.'
Here is pure fable,
not legend,
but still a curious forecast of twentieth century bombs from a rigid dirigible.
It is
to be noted in this case,
as in many,
that the power
to fly was an attribute of evil,
not of good--it was the demons who built the chariot,
even as at Friedrichshavn.
Mediaeval legend in nearly every cas,attributes flight
to the aid of evil powers,
and incites well-disposed people
to stick
to the solid earth--though,
curiously enough,
the pioneers of medieval times were very largely of priestly type,
as witness the monk of Malmesbury.
The legends of the dawn of history,
however,
distribute the power of flight
with less of prejudice.
Egyptian sculpture gives the figure of winged men;
the British Museum has made the winged Assyrian bulls familiar
to many,
and both the cuneiform records of Assyria and the hieroglyphs of Egypt record flights that in reality were never made.
The desire fathered the story then,
and until Clement Ader either hopped
with his Avion,
as is persisted by his critics,
or flew,
as is claimed by his friends.
While the origin of many legends is questionable,
that of others is easy enough
to trace,
though not
to prove.
Among the credulous the significance of the name of a people of Asia Minor,
the Capnobates,
'those who travel by smoke,'
gave rise
to the assertion that Montgolfier was not first in the field--or rather in the air--since surely this people must have been responsible
for the first hot-air balloons.
Far less questionable is the legend of Icarus,
for here it is possible
to trace a foundation of fact in the story.
Such a tribe as Daedalus governed could have had hardly any knowledge of the rudiments of science,
and even their ruler,
seeing how easy it is
for birds
to sustain themselves in the air,
might be excused
for believing that he,
if he fashioned wings
for himself,
could use them.
In that belief,
let it be assumed,
Daedalus made his wings;
the boy,
Icarus,
learning that his father had determined on an attempt at flight secured the wings and fastened them
to his own shoulders.
A cliff seemed the likeliest place
for a
'take-off,'
and Icarus leaped from the cliff edge only
to find that the possession of wings was not enough
to assure flight
to a human being.
The sea that
to this day bears his name witnesses that he made the attempt and perished by it.
In this is assumed the bald story,
from which might grow the legend of a wise king who ruled a peaceful people--'judged,
sitting in the sun,'
as Browning has it,
and fashioned
for himself wings
with which he flew over the sea and where he would,
until the prince,
Icarus,
desired
to emulate him.
Icarus,
fastening the wings
to his shoulders
with wax,
was so imprudent as
to fly too near the sun,
when the wax melted and he fell,
to lie mourned of water-nymphs on the shores of waters thenceforth Icarian.
Between what we have assumed
to be the base of fact,
and the legend which has been invested
with such poetic grace in Greek story,
there is no more than a century or so of re-telling might give
to any event among a people so simple and yet so given
to imagery.
We may set aside as pure fable the stories of the winged horse of Perseus,
and the flights of Hermes as messenger of the gods.
With them may be placed the story of Empedocles,
who failed
to take Etna seriously enough,
and found himself caught by an eruption while within the crater,
so that,
flying
to safety in some hurry,
he left behind but one sandal
to attest that he had sought refuge in space--in all probability,
if he escaped at all,
he flew,
but not in the sense that the aeronaut understands it.
But,
bearing in mind the many men who tried
to fly in historic times,
the legend of Icarus and Daedalus,
in spite of the impossible form in which it is presented,
may rank
with the story of the Saracen of Constantinople,
or
with that of Simon the Magician.
A simple folk would naturally idealise the man and magnify his exploit,
as they magnified the deeds of some strong man
to make the legends of Hercules,
and there,
full-grown from a mere legend,
is the first record of a pioneer of flying.
Such a theory is not nearly so fantastic as that which makes the Capnobates,
on the strength of their name,
the inventors of hot-air balloons.
However it may be,
both in story and in picture,
Icarus and his less conspicuous father have inspired the Caucasian mind,
and the world is the richer
for them.
Of the unsupported myths--unsupported,
that is,
by even a shadow of probability--there is no end.
Although Latin legend approaches nearer
to fact than the Greek in some cases,
in others it shows a disregard
for possibilities which renders it of far less account.
Thus Diodorus of Sicily relates that one Abaris travelled round the world on an arrow of gold,
and Cassiodorus and Glycas and their like told of mechanical birds that flew and sang and even laid eggs.
More credible is the story of Aulus Gellius,
who in his Attic Nights tells how Archytas,
four centuries prior
to the opening of the Christian era,
made a wooden pigeon that actually flew by means of a mechanism of balancing weights and the breath of a mysterious spirit hidden within it.
There may yet arise one credulous enough
to state that the mysterious spirit was precursor of the internal combustion engine,
but,
however that may be,
the pigeon of Archytas almost certainly existed,
and perhaps it actually glided or flew
for short distances--or else Aulus Gellius was an utter liar,
like Cassiodorus and his fellows.
In far later times a certain John Muller,
better known as Regiomontanus,
is stated
to have made an artificial eagle which accompanied Charles V.
on his entry
to and exit from Nuremberg,
flying above the royal procession.
But,
since Muller died in 1436 and Charles was born in 1500,
Muller may be ruled out from among the pioneers of mechanical flight,
and it may be concluded that the historian of this event got slightly mixed in his dates.
Thus far,
we have but indicated how one may draw from the richest stores from which the Aryan mind draws inspiration,
the Greek and Latin mythologies and poetic adaptations of history.
The existing legends of flight,
however,
are not thus
to be localised,
for
with two possible exceptions they belong
to all the world and
to every civilisation,
however primitive.
The two exceptions are the Aztec and the Chinese;
regarding the first of these,
the Spanish conquistadores destroyed such civilisation as existed in Tenochtitlan so thoroughly that,
if legend of flight was among the Aztec records,
it went
with the rest;
as
to the Chinese,
it is more than passing strange that they,
who claim
to have known and done everything while the first of history was shaping,
even
to antedating the discovery of gunpowder that was not made by Roger Bacon,
have not yet set up a claim
to successful handling of a monoplane some four thousand years ago,
or at least
to the patrol of the Gulf of Korea and the Mongolian frontier by a forerunner of the
'blimp.'
The Inca civilisation of Peru yields up a myth akin
to that of Icarus,
which tells how the chieftain Ayar Utso grew wings and visited the sun--it was from the sun,
too,
that the founders of the Peruvian Inca dynasty,
Manco Capac and his wife Mama Huella Capac,
flew
to earth near Lake Titicaca,
to make the only successful experiment in pure tyranny that the world has ever witnessed.
Teutonic legend gives forth Wieland the Smith,
who made himself a dress
with wings and,
clad in it,
rose and descended against the wind and in spite of it.
Indian mythology,
in addition
to the story of the demons and their rigid dirigible,
already quoted,
gives the story of Hanouam,
who fitted himself
with wings by means of which he sailed in the air and,
according
to his desire,
landed in the sacred Lauka.
Bladud,
the ninth king of Britain,
is said
to have crowned his feats of wizardry by making himself wings and attempting
to fly--but the effort cost him a broken neck.
Bladud may have been as mythic as Uther,
and again he may have been a very early pioneer.
The Finnish epic,
'Kalevala,'
tells how Ilmarinen the Smith
'forged an eagle of fire,'
with
'boat's walls between the wings,'
after which he
'sat down on the bird's back and bones,'
and flew.
Pure myths,
these,
telling how the desire
to fly was characteristic of every age and every people,
and how,
from time
to time,
there arose an experimenter bolder than his fellows,
who made some attempt
to translate desire into achievement.
And the spirit that animated these pioneers,
in a time when things new were accounted things accursed,
for the most part,
has found expression in this present century in the utter daring and disregard of both danger and pain that stamps the flying man,
a type of humanity differing in spirit from his earthbound fellows as fully as the soldier differs from the priest.
Throughout mediaeval times,
records attest that here and there some man believed in and attempted flight,
and at the same time it is clear that such were regarded as in league
with the powers of evil.
There is the half-legend,
half-history of Simon the Magician,
who,
in the third year of the reign of Nero announced that he would raise himself in the air,
in order
to assert his superiority over St Paul.
The legend states that by the aid of certain demons whom he had prevailed on
to assist him,
he actually lifted himself in the air-- but St Paul prayed him down again.
He slipped through the claws of the demons and fell headlong on the Forum at Rome,
breaking his neck.
The
'demons'
may have been some primitive form of hot-air balloon,
or a glider
with which the magician attempted
to rise into the wind;
more probably,
however,
Simon threatened
to ascend and made the attempt
with apparatus as unsuitable as Bladud's wings,
paying the inevitable penalty.
Another version of the story gives St Peter instead of St Paul as the one whose prayers foiled Simon --apart from the identity of the apostle,
the two accounts are similar,
and both define the attitude of the age toward investigation and experiment in things untried.
Another and later circumstantial story,
with similar evidence of some fact behind it,
is that of the Saracen of Constantinople,
who,
in the reign of the Emperor Comnenus--some little time before Norman William made Saxon Harold swear away his crown on the bones of the saints at Rouen--attempted
to fly round the hippodrome at Constantinople,
having Comnenus among the great throng who gathered
to witness the feat.
The Saracen chose
for his starting-point a tower in the midst of the hippodrome,
and on the top of the tower he stood,
clad in a long white robe which was stiffened
with rods so as
to spread and catch the breeze,
waiting
for a favourable wind
to strike on him.
The wind was so long in coming that the spectators grew impatient.
'Fly,
O Saracen!'
they called
to him.
'Do not keep us waiting so long while you try the wind!'
Comnenus,
who had present
with him the Sultan of the Turks,
gave it as his opinion that the experiment was both dangerous and vain,
and,
possibly in an attempt
to controvert such statement,
the Saracen leaned into the wind and
'rose like a bird
'at the outset.
But the record of Cousin,
who tells the story in his Histoire de Constantinople,
states that
'the weight of his body having more power
to drag him down than his artificial wings had
to sustain him,
he broke his bones,
and his evil plight was such that he did not long survive.'
Obviously,
the Saracen was anticipating Lilienthal and his gliders by some centuries;
like Simon,
a genuine experimenter--both legends bear the impress of fact supporting them.
Contemporary
with him,
and belonging
to the history rather than the legends of flight,
was Oliver,
the monk of Malmesbury,
who in the year 1065 made himself wings after the pattern of those supposed
to have been used by Daedalus,
attaching them
to his hands and feet and attempting
to fly
with them.
Twysden,
in his Historiae Anglicanae Scriptores X,
sets forth the story of Oliver,
who chose a high tower as his starting-point,
and launched himself in the air.
As a matter of course,
he fell,
permanently injuring himself,
and died some time later.
After these,
a gap of centuries,
filled in by impossible stories of magical flight by witches,
wizards,
and the like--imagination was fertile in the dark ages,
but the ban of the church was on all attempt at scientific development,
especially in such a matter as the conquest of the air.
Yet there were observers of nature who argued that since birds could raise themselves by flapping their wings,
man had only
to make suitable wings,
flap them,
and he too would fly.
As early as the thirteenth century Roger Bacon,
the scientific friar of unbounded inquisitiveness and not a little real genius,
announced that there could be made
'some flying instrument,
so that a man sitting in the middle and turning some mechanism may put in motion some artificial wings which may beat the air like a bird flying.'
But being a cautious man,
with a natural dislike
for being burnt at the stake as a necromancer through having put forward such a dangerous theory,
Roger added,
'not that I ever knew a man who had such an instrument,
but I am particularly acquainted
with the man who contrived one.'
This might have been a lame defence if Roger had been brought
to trial as addicted
to black arts;
he seems
to have trusted
to the inadmissibility of hearsay evidence.
Some four centuries later there was published a book entitled Perugia Augusta,
written by one C.
Crispolti of Perugia--the date of the work in question is 1648.
In it is recorded that
'one day,
towards the close of the fifteenth century,
whilst many of the principal gentry had come
to Perugia
to honour the wedding of Giovanni Paolo Baglioni,
and some lancers were riding down the street by his palace,
Giovanni Baptisti Danti unexpectedly and by means of a contrivance of wings that he had constructed proportionate
to the size of his body took off from the top of a tower near by,
and
with a horrible hissing sound flew successfully across the great Piazza,
which was densely crowded.
But
(oh,
horror of an unexpected accident!)
he had scarcely flown three hundred paces on his way
to a certain point when the mainstay of the left wing gave way,
and,
being unable
to support himself
with the right alone,
he fell on a roof and was injured in consequence.
Those who saw not only this flight,
but also the wonderful construction of the framework of the wings,
said--and tradition bears them out--that he several times flew over the waters of Lake Thrasimene
to learn how he might gradually come
to earth.
But,
notwithstanding his great genius,
he never succeeded.'
This reads circumstantially enough,
but it may be borne in mind that the date of writing is more than half a century later than the time of the alleged achievement--the story had had time
to round itself out.
Danti,
however,
is mentioned by a number of writers,
one of whom states that the failure of his experiment was due
to the prayers of some individual of a conservative turn of mind,
who prayed so vigorously that Danti fell appropriately enough on a church and injured himself
to such an extent as
to put an end
to his flying career.
That Danti experimented,
there is little doubt,
in view of the volume of evidence on the point,
but the darkness of the Middle Ages hides the real truth as
to the results of his experiments.
If he had actually flown over Thrasimene,
as alleged,
then in all probability both Napoleon and Wellington would have had air scouts at Waterloo.
Danti's story may be taken as fact or left as fable,
and
with it the period of legend or vague statement may be said
to end--the rest is history,
both of genuine experimenters and of charlatans.
Such instances of legend as are given here are not a tithe of the whole,
but there is sufficient in the actual history of flight
to bar out more than this brief mention of the legends,
which,
on the whole,
go farther
to prove man's desire
to fly than his study and endeavour
to solve the problems of the air.
II.
EARLY EXPERIMENTS So far,
the stories of the development of flight are either legendary or of more or less doubtful authenticity,
even including that of Danti,
who,
although a man of remarkable attainments in more directions than that of attempted flight,
suffers--so far as reputation is concerned--from the inexactitudes of his chroniclers;
he may have soared over Thrasimene,
as stated,
or a mere hop
with an ineffectual glider may have grown
with the years
to a legend of gliding flight.
So far,
too,
there is no evidence of the study that the conquest of the air demanded;
such men as made experiments either launched themselves in the air from some height
with made-up wings or other apparatus,
and paid the penalty,
or else constructed some form of machine which would not leave the earth,
and then gave up.
Each man followed his own way,
and there was no attempt--without the printing press and the dissemination of knowledge there was little possibility of attempt--on the part of any one
to benefit by the failures of others.
Legend and doubtful history carries up
to the fifteenth century,
and then came Leonardo da Vinci,
first student of flight whose work endures
to the present day.
The world knows da Vinci as artist;
his age knew him as architect,
engineer,
artist,
and scientist in an age when science was a single study,
comprising all knowledge from mathematics
to medicine.
He was,
of course,
in league
with the devil,
for in no other way could his range of knowledge and observation be explained by his contemporaries;
he left a Treatise on the Flight of Birds in which are statements and deductions that had
to be rediscovered when the Treatise had been forgotten--da Vinci anticipated modern knowledge as Plato anticipated modern thought,
and blazed the first broad trail toward flight.
One Cuperus,
who wrote a Treatise on the Excellence of Man,
asserted that da Vinci translated his theories into practice,
and actually flew,
but the statement is unsupported.
That he made models,
especially on the helicopter principle,
is past question;
these were made of paper and wire,
and actuated by springs of steel wire,
which caused them
to lift themselves in the air.
It is,
however,
in the theories which he put forward that da Vinci's investigations are of greatest interest;
these prove him a patient as well as a keen student of the principles of flight,
and show that his manifold activities did not prevent him from devoting some lengthy periods
to observations of bird flight.
'A bird,'
he says in his Treatise,
'is an instrument working according
to mathematical law,
which instrument it is within the capacity of man
to reproduce
with all its movements,
but not
with a corresponding degree of strength,
though it is deficient only in power of maintaining equilibrium.
We may say,
therefore,
that such an instrument constructed by man is lacking in nothing except the life of the bird,
and this life must needs be supplied from that of man.
The life which resides in the bird's members will,
without doubt,
better conform
to their needs than will that of a man which is separated from them,
and especially in the almost imperceptible movements which produce equilibrium.
But since we see that the bird is equipped
for many apparent varieties of movement,
we are able from this experience
to deduce that the most rudimentary of these movements will be capable of being comprehended by man's understanding,
and that he will
to a great extent be able
to provide against the destruction of that instrument of which he himself has become the living principle and the propeller.'
In this is the definite belief of da Vinci that man is capable of flight,
together
with a far more definite statement of the principles by which flight is
to be achieved than any which had preceded it--and
for that matter,
than many that have succeeded it.
Two further extracts from his work will show the exactness of his observations:--
'When a bird which is in equilibrium throws the centre of resistance of the wings behind the centre of gravity,
then such a bird will descend
with its head downward.
This bird which finds itself in equilibrium shall have the centre of resistance of the wings more forward than the bird's centre of gravity;
then such a bird will fall
with its tail turned toward the earth.'
And again:
'A man,
when flying,
shall be free from the waist up,
that he may be able
to keep himself in equilibrium as he does in a boat,
so that the centre of his gravity and of the instrument may set itself in equilibrium and change when necessity requires it
to the changing of the centre of its resistance.'
Here,
in this last quotation,
are the first beginnings of the inherent stability which proved so great an advance in design,
in this twentieth century.
But the extracts given do not begin
to exhaust the range of da Vinci's observations and deductions.
With regard
to bird flight,
he observed that so long as a bird keeps its wings outspread it cannot fall directly
to earth,
but must glide down at an angle
to alight--a small thing,
now that the principle of the plane in opposition
to the air is generally grasped,
but da Vinci had
to find it out.
From observation he gathered how a bird checks its own speed by opposing tail and wing surface
to the direction of flight,
and thus alights at the proper
'landing speed.'
He proved the existence of upward air currents by noting how a bird takes off from level earth
with wings outstretched and motionless,
and,
in order
to get an efficient substitute
for the natural wing,
he recommended that there be used something similar
to the membrane of the wing of a bat--from this
to the doped fabric of an aeroplane wing is but a small step,
for both are equally impervious
to air.
Again,
da Vinci recommended that experiments in flight be conducted at a good height from the ground,
since,
if equilibrium be lost through any cause,
the height gives time
to regain it.
This recommendation,
by the way,
received ample support in the training areas of war pilots.
Man's muscles,
said da Vinci,
are fully sufficient
to enable him
to fly,
for the larger birds,
he noted,
employ but a small part of their strength in keeping themselves afloat in the air--by this theory he attempted
to encourage experiment,
just as,
when his time came,
Borelli reached the opposite conclusion and discouraged it.
That Borelli was right--so far--and da Vinci wrong,
detracts not at all from the repute of the earlier investigator,
who had but the resources of his age
to support investigations conducted in the spirit of ages after.
His chief practical contributions
to the science of flight--apart from numerous drawings which have still a value--are the helicopter or lifting screw,
and the parachute.
The former,
as already noted,
he made and proved effective in model form,
and the principle which he demonstrated is that of the helicopter of to-day,
on which sundry experimenters work spasmodically,
in spite of the success of the plane
with its driving propeller.
As
to the parachute,
the idea was doubtless inspired by observation of the effect a bird produced by pressure of its wings against the direction of flight.
Da Vinci's conclusions,
and his experiments,
were forgotten easily by most of his contemporaries;
his Treatise lay forgotten
for nearly four centuries,
overshadowed,
mayhap,
by his other work.
There was,
however,
a certain Paolo Guidotti of Lucca,
who lived in the latter half of the sixteenth century,
and who attempted
to carry da Vinci's theories--one of them,
at least,
into practice.
For this Guidotti,
who was by profession an artist and by inclination an investigator,
made
for himself wings,
of which the framework was of whalebone;
these he covered
with feathers,
and
with them made a number of gliding flights,
attaining considerable proficiency.
He is said in the end
to have made a flight of about four hundred yards,
but this attempt at solving the problem ended on a house roof,
where Guidotti broke his thigh bone.
After that,
apparently,
he gave up the idea of flight,
and went back
to painting.
One other a Venetian architect named Veranzio.
studied da Vinci's theory of the parachute,
and found it correct,
if contemporary records and even pictorial presentment are correct.
Da Vinci showed his conception of a parachute as a sort of inverted square bag;
Veranzio modified this
to a
'sort of square sail extended by four rods of equal size and having four cords attached at the corners,'
by means of which
'a man could without danger throw himself from the top of a tower or any high place.
For though at the moment there may be no wind,
yet the effort of his falling will carry up the wind,
which the sail will hold,
by which means he does not fall suddenly but descends little by little.
The size of the sail should be measured
to the man.'
By this last,
evidently,
Veranzio intended
to convey that the sheet must be of such content as would enclose sufficient air
to support the weight of the parachutist.
Veranzio made his experiments about 1617-1618,
but,
naturally,
they carried him no farther than the mere descent
to earth,
and since a descent is merely a descent,
it is
to be conjectured that he soon got tired of dropping from high roofs,
and took
to designing architecture instead of putting it
to such a use.
With the end of his experiments the work of da Vinci in relation
to flying became neglected
for nearly four centuries.
Apart from these two experimenters,
there is little
to record in the matter either of experiment or study until the seventeenth century.
Francis Bacon,
it is true,
wrote about flying in his Sylva Sylvarum,
and mentioned the subject in the New Atlantis,
but,
except
for the insight that he showed even in superficial mention of any specific subject,
he does not appear
to have made attempt at serious investigation.
'Spreading of Feathers,
thin and close and in great breadth will likewise bear up a great Weight,'
says Francis,
'being even laid without Tilting upon the sides.'
But a lesser genius could have told as much,
even in that age,
and though the great Sir Francis is sometimes adduced as one of the early students of the problems of flight,
his writings will not sustain the reputation.
The seventeenth century,
however,
gives us three names,
those of Borelli,
Lana,
and Robert Hooke,
all of which take definite place in the history of flight.
Borelli ranks as one of the great figures in the study of aeronautical problems,
in spite of erroneous deductions through which he arrived at a purely negative conclusion
with regard
to the possibility of human flight.
Borelli was a versatile genius.
Born in 1608,
he was practically contemporary
with Francesco Lana,
and there is evidence that he either knew or was in correspondence
with many prominent members of the Royal Society of Great Britain,
more especially
with John Collins,
Dr Wallis,
and Henry Oldenburgh,
the then Secretary of the Society.
He was author of a long list of scientific essays,
two of which only are responsible
for his fame,
viz.,
Theorice Medicaearum Planetarum,
published in Florence,
and the better known posthumous De Motu Animalium.
The first of these two is an astronomical study in which Borelli gives evidence of an instinctive knowledge of gravitation,
though no definite expression is given of this.
The second work,
De Motu Animalium,
deals
with the mechanical action of the limbs of birds and animals and
with a theory of the action of the internal organs.
A section of the first part of this work,
called De Volatu,
is a study of bird flight;
it is quite independent of Da Vinci's earlier work,
which had been forgotten and remained unnoticed until near on the beginning of practical flight.
Marey,
in his work,
La Machine Animale,
credits Borelli
with the first correct idea of the mechanism of flight.
He says:
'Therefore we must be allowed
to render
to the genius of Borelli the justice which is due
to him,
and only claim
for ourselves the merit of having furnished the experimental demonstration of a truth already suspected.'
In fact,
all subsequent studies on this subject concur in making Borelli the first investigator who illustrated the purely mechanical theory of the action of a bird's wings.
Borelli's study is divided into a series of propositions in which he traces the principles of flight,
and the mechanical actions of the wings of birds.
The most interesting of these are the propositions in which he sets forth the method in which birds move their wings during flight and the manner in which the air offers resistance
to the stroke of the wing.
With regard
to the first of these two points he says:
'When birds in repose rest on the earth their wings are folded up close against their flanks,
but when wishing
to start on their flight they first bend their legs and leap into the air.
Whereupon the joints of their wings are straightened out
to form a straight line at right angles
to the lateral surface of the breast,
so that the two wings,
outstretched,
are placed,
as it were,
like the arms of a cross
to the body of the bird.
Next,
since the wings
with their feathers attached form almost a plane surface,
they are raised slightly above the horizontal,
and
with a most quick impulse beat down in a direction almost perpendicular
to the wing-plane,
upon the underlying air;
and
to so intense a beat the air,
notwithstanding it
to be fluid,
offers resistance,
partly by reason of its natural inertia,
which seeks
to retain it at rest,
and partly because the particles of the air,
compressed by the swiftness of the stroke,
resist this compression by their elasticity,
just like the hard ground.
Hence the whole mass of the bird rebounds,
making a fresh leap through the air;
whence it follows that flight is simply a motion composed of successive leaps accomplished through the air.
And I remark that a wing can easily beat the air in a direction almost perpendicular
to its plane surface,
although only a single one of the corners of the humerus bone is attached
to the scapula,
the whole extent of its base remaining free and loose,
while the greater transverse feathers are joined
to the lateral skin of the thorax.
Nevertheless the wing can easily revolve about its base like unto a fan.
Nor are there lacking tendon ligaments which restrain the feathers and prevent them from opening farther,
in the same fashion that sheets hold in the sails of ships.
No less admirable is nature's cunning in unfolding and folding the wings upwards,
for she folds them not laterally,
but by moving upwards edgewise the osseous parts wherein the roots of the feathers are inserted;
for thus,
without encountering the air's resistance the upward motion of the wing surface is made as
with a sword,
hence they can be uplifted
with but small force.
But thereafter when the wings are twisted by being drawn transversely and by the resistance of the air,
they are flattened as has been declared and will be made manifest hereafter.'
Then
with reference
to the resistance
to the air of the wings he explains:
'The air when struck offers resistance by its elastic virtue through which the particles of the air compressed by the wing-beat strive
to expand again.
Through these two causes of resistance the downward beat of the wing is not only opposed,
but even caused
to recoil
with a reflex movement;
and these two causes of resistance ever increase the more the down stroke of the wing is maintained and accelerated.
On the other hand,
the impulse of the wing is continuously diminished and weakened by the growing resistance.
Hereby the force of the wing and the resistance become balanced;
so that,
manifestly,
the air is beaten by the wing
with the same force as the resistance
to the stroke.'
He concerns himself also
with the most difficult problem that confronts the flying man of to-day,
namely,
landing effectively,
and his remarks on this subject would be instructive even
to an air pilot of these days:
'Now the ways and means by which the speed is slackened at the end of a flight are these.
The bird spreads its wings and tail so that their concave surfaces are perpendicular
to the direction of motion;
in this way,
the spreading feathers,
like a ship's sail,
strike against the still air,
check the speed,
and so that most of the impetus may be stopped,
the wings are flapped quickly and strongly forward,
inducing a contrary motion,
so that the bird absolutely or very nearly stops.'
At the end of his study Borelli came
to a conclusion which militated greatly against experiment
with any heavier-than-air apparatus,
until well on into the nineteenth century,
for having gone thoroughly into the subject of bird flight he states distinctly in his last proposition on the subject that
'It is impossible that men should be able
to fly craftily by their own strength.'
This statement,
of course,
remains true up
to the present day
for no man has yet devised the means by which he can raise himself in the air and maintain himself there by mere muscular effort.
From the time of Borelli up
to the development of the steam engine it may be said that flight by means of any heavier-than-air apparatus was generally regarded as impossible,
and apart from certain deductions which a little experiment would have shown
to be doomed
to failure,
this method of flight was not followed up.
It is not
to be wondered at,
when Borelli's exaggerated estimate of the strength expended by birds in proportion
to their weight is borne in mind;
he alleged that the motive force in birds'
wings is 10,000 times greater than the resistance of their weight,
and
with regard
to human flight he remarks:--
'When,
therefore,
it is asked whether men may be able
to fly by their own strength,
it must be seen whether the motive power of the pectoral muscles
(the strength of which is indicated and measured by their size)
is proportionately great,
as it is evident that it must exceed the resistance of the weight of the whole human body 10,000 times,
together
with the weight of enormous wings which should be attached
to the arMs. And it is clear that the motive power of the pectoral muscles in men is much less than is necessary
for flight,
for in birds the bulk and weight of the muscles
for flapping the wings are not less than a sixth part of the entire weight of the body.
Therefore,
it would be necessary that the pectoral muscles of a man should weigh more than a sixth part of the entire weight of his body;
so also the arms,
by flapping
with the wings attached,
should be able
to exert a power 10,000 times greater than the weight of the human body itself.
But they are far below such excess,
for the aforesaid pectoral muscles do not equal a hundredth part of the entire weight of a man.
Wherefore either the strength of the muscles ought
to be increased or the weight of the human body must be decreased,
so that the same proportion obtains in it as exists in birds.
Hence it is deducted that the Icarian invention is entirely mythical because impossible,
for it is not possible either
to increase a man's pectoral muscles or
to diminish the weight of the human body;
and whatever apparatus is used,
although it is possible
to increase the momentum,
the velocity or the power employed can never equal the resistance;
and therefore wing flapping by the contraction of muscles cannot give out enough power
to carry up the heavy body of a man.'
It may be said that practically all the conclusions which Borelli reached in his study were negative.
Although contemporary
with Lana,
he perceived the one factor which rendered Lana's project
for flight by means of vacuum globes an impossibility--he saw that no globe could be constructed sufficiently light
for flight,
and at the same time sufficiently strong
to withstand the pressure of the outside atmosphere.
He does not appear
to have made any experiments in flying on his own account,
having,
as he asserts most definitely,
no faith in any invention designed
to lift man from the surface of the earth.
But his work,
from which only the foregoing short quotations can be given,
is,
nevertheless,
of indisputable value,
for he settled the mechanics of bird flight,
and paved the way
for those later investigators who had,
first,
the steam engine,
and later the internal combustion engine--two factors in mechanical flight which would have seemed as impossible
to Borelli as would wireless telegraphy
to a student of Napoleonic times.
On such foundations as his age afforded Borelli built solidly and well,
so that he ranks as one of the greatest--if not actually the greatest--of the investigators into this subject before the age of steam.
The conclusion,
that
'the motive force in birds'
wings is apparently ten thousand times greater than the resistance of their weight,'
is erroneous,
of course,
but study of the translation from which the foregoing excerpt is taken will show that the error detracts very little from the value of the work itself.
Borelli sets out very definitely the mechanism of flight,
in such fashion that he who runs may read.
His reference to
'the use of a large vessel,'
etc.,
concerns the suggestion made by Francesco Lana,
who antedated Borelli's publication of De Motu Animalium by some ten years
with his suggestion
for an
'aerial ship,'
as he called it.
Lana's mind shows,
as regards flight,
a more imaginative twist;
Borelli dived down into first causes,
and reached mathematical conclusions;
Lana conceived a theory and upheld it-- theoretically,
since the manner of his life precluded experiment.
Francesco Lana,
son of a noble family,
was born in 1631;
in 1647 he was received as a novice into the Society of Jesus at Rome,
and remained a pious member of the Jesuit society until the end of his life.
He was greatly handicapped in his scientific investigations by the vows of poverty which the rules of the Order imposed on him.
He was more scientist than priest all his life;
for two years he held the post of Professor of Mathematics at Ferrara,
and up
to the time of his death,
in 1687,
he spent by far the greater part of his time in scientific research,
He had the dubious advantage of living in an age when one man could cover the whole range of science,
and this he seems
to have done very thoroughly.
There survives an immense work of his entitled,
Magisterium Naturae et Artis,
which embraces the whole field of scientific knowledge as that was developed in the period in which Lana lived.
In an earlier work of his,
published in Brescia in 1670,
appears his famous treatise on the aerial ship,
a problem which Lana worked out
with thoroughness.
He was unable
to make practical experiments,
and thus failed
to perceive the one insuperable drawback
to his project--of which more anon.
Only extracts from the translation of Lana's work can be given here,
but sufficient can be given
to show fully the means by which he designed
to achieve the conquest of the air.
He begins by mention of the celebrated pigeon of Archytas the Philosopher,
and advances one or two theories
with regard
to the way in which this mechanical bird was constructed,
and then he recites,
apparently
with full belief in it,
the fable of Regiomontanus and the eagle that he is said
to have constructed
to accompany Charles V.
on his entry into Nuremberg.
In fact,
Lana starts his work
with a study of the pioneers of mechanical flying up
to his own time,
and then outlines his own devices
for the construction of mechanical birds before proceeding
to detail the construction of the aerial ship.
Concerning primary experiments
for this he says:--
'I will,
first of all,
presuppose that air has weight owing
to the vapours and halations which ascend from the earth and seas
to a height of many miles and surround the whole of our terraqueous globe;
and this fact will not be denied by philosophers,
even by those who may have but a superficial knowledge.
because it can be proven by exhausting,
if not all,
at any rate the greater part of,
the air contained in a glass vessel,
which,
if weighed before and after the air has been exhausted,
will be found materially reduced in weight.
Then I found out how much the air weighed in itself in the following manner.
I procured a large vessel of glass,
whose neck could be closed or opened by means of a tap,
and holding it open I warmed it over a fire,
so that the air inside it becoming rarified,
the major part was forced out;
then quickly shutting the tap
to prevent the re-entry I weighed it;
which done,
I plunged its neck in water,
resting the whole of the vessel on the surface of the water,
then on opening the tap the water rose in the vessel and filled the greater part of it.
I lifted the neck out of the water,
released the water contained in the vessel,
and measured and weighed its quantity and density,
by which I inferred that a certain quantity of air had come out of the vessel equal in bulk
to the quantity of water which had entered
to refill the portion abandoned by the air.
I again weighed the vessel,
after I had first of all well dried it free of all moisture,
and found it weighed one ounce more whilst it was full of air than when it was exhausted of the greater part,
so that what it weighed more was a quantity of air equal in volume
to the water which took its place.
The water weighed 640 ounces,
so I concluded that the weight of air compared
with that of water was 1
to 640--that is
to say,
as the water which filled the vessel weighed 640 ounces,
so the air which filled the same vessel weighed one ounce.'
Having thus detailed the method of exhausting air from a vessel,
Lana goes on
to assume that any large vessel can be entirely exhausted of nearly all the air contained therein.
Then he takes Euclid's proposition
to the effect that the superficial area of globes increases in the proportion of the square of the diameter,
whilst the volume increases in the proportion of the cube of the same diameter,
and he considers that if one only constructs the globe of thin metal,
of sufficient size,
and exhausts the air in the manner that he suggests,
such a globe will be so far lighter than the surrounding atmosphere that it will not only rise,
but will be capable of lifting weights.
Here is Lana's own way of putting it:--
'But so that it may be enabled
to raise heavier weights and
to lift men in the air,
let us take double the quantity of copper,
1,232 square feet,
equal
to 308 lbs.
of copper;
with this double quantity of copper we could construct a vessel of not only double the capacity,
but of four times the capacity of the first,
for the reason shown by my fourth supposition.
Consequently the air contained in such a vessel will be 718 lbs.
4 2/3 ounces,
so that if the air be drawn out of the vessel it will be 410 lbs.
4 2/3 ounces lighter than the same volume of air,
and,
consequently,
will be enabled
to lift three men,
or at least two,
should they weigh more than eight pesi each.
It is thus manifest that the larger the ball or vessel is made,
the thicker and more solid can the sheets of copper be made,
because,
although the weight will increase,
the capacity of the vessel will increase
to a greater extent and
with it the weight of the air therein,
so that it will always be capable
to lift a heavier weight.
From this it can be easily seen how it is possible
to construct a machine which,
fashioned like unto a ship,
will float on the air.'
With four globes of these dimensions Lana proposed
to make an aerial ship of the fashion shown in his quaint illustration.
He is careful
to point out a method by which the supporting globes
for the aerial ship may be entirely emptied of air;
this is
to be done by connecting
to each globe a tube of copper which is
'at least a length of 47 modern Roman palm).'
A small tap is
to close this tube at the end nearest the globe,
and then vessel and tube are
to be filled
with water,
after which the tube is
to be immersed in water and the tap opened,
allowing the water
to run out of the vessel,
while no air enters.
The tap is then closed before the lower end of the tube is removed from the water,
leaving no air at all in the globe or sphere.
Propulsion of this airship was
to be accomplished by means of sails,
and also by oars.
Lana antedated the modern propeller,
and realised that the air would offer enough resistance
to oars or paddle
to impart motion
to any vessel floating in it and propelled by these means,
although he did not realise the amount of pressure on the air which would be necessary
to accomplish propulsion.
As a matter of fact,
he foresaw and provided against practically all the difficulties that would be encountered in the working,
as well as the making,
of the aerial ship,
finally coming up against what his religious training made an insuperable objection.
This,
again,
is best told in his own words:--
'Other difficulties I do not foresee that could prevail against this invention,
save one only,
which
to me seems the greatest of them all,
and that is that God would surely never allow such a machine
to be successful,
since it would create many disturbances in the civil and political governments of mankind.'
He ends by saying that no city would be proof against surprise,
while the aerial ship could set fire
to vessels at sea,
and destroy houses,
fortresses,
and cities by fire balls and bombs.
In fact,
at the end of his treatise on the subject,
he furnishes a pretty complete resume of the activities of German Zeppelins.
As already noted,
Lana himself,
owing
to his vows of poverty,
was unable
to do more than put his suggestions on paper,
which he did
with a thoroughness that has procured him a place among the really great pioneers of flying.
It was nearly 200 years before any attempt was made
to realise his project;
then,
in 1843,
M.
Marey Monge set out
to make the globes and the ship as Lana detailed them.
Monge's experiments cost him the sum of 25,000 francs 75 centimes,
which he expended purely from love of scientific investigation.
He chose
to make his globes of brass,
about .004 in thickness,
and weighing 1.465 lbs.
to the square yard.
Having made his sphere of this metal,
he lined it
with two thicknesses of tissue paper,
varnished it
with oil,
and set
to work
to empty it of air.
This,
however,
he never achieved,
for such metal is incapable of sustaining the pressure of the outside air,
as Lana,
had he had the means
to carry out experiments,
would have ascertained.
M.
Monge's sphere could never be emptied of air sufficiently
to rise from the earth;
it ended in the melting-pot,
ignominiously enough,
and all that Monge got from his experiment was the value of the scrap metal and the satisfaction of knowing that Lana's theory could never be translated into practice.
Robert Hooke is less conspicuous than either Borelli or Lana;
his work,
which came into the middle of the seventeenth century,
consisted of various experiments
with regard
to flight,
from which emerged
'a Module,
which by the help of Springs and Wings,
raised and sustained itself in the air.'
This must be reckoned as the first model flying machine which actually flew,
except
for da Vinci's helicopters;
Hooke's model appears
to have been of the flapping-wing type--he attempted
to copy the motion of birds,
but found from study and experiment that human muscles were not sufficient
to the task of lifting the human body.
For that reason,
he says,
'I applied my mind
to contrive a way
to make artificial muscles,'
but in this he was,
as he expresses it,
'frustrated of my expectations.'
Hooke's claim
to fame rests mainly on his successful model;
the rest of his work is of too scrappy a nature
to rank as a serious contribution
to the study of flight.
Contemporary
with Hooke was one Allard,
who,
in France,
undertook
to emulate the Saracen of Constantinople
to a certain extent.
Allard was a tight-rope dancer who either did or was said
to have done short gliding flights--the matter is open
to question--and finally stated that he would,
at St Germains,
fly from the terrace in the king's presence.
He made the attempt,
but merely fell,
as did the Saracen some centuries before,
causing himself serious injury.
Allard cannot be regarded as a contributor
to the development of aeronautics in any way,
and is only mentioned as typical of the way in which,
up
to the time of the Wright brothers,
flying was regarded.
Even unto this day there are many who still believe that,
with a pair of wings,
man ought
to be able
to fly,
and that the mathematical data necessary
to effective construction simply do not exist.
This attitude was reasonable enough in an unlearned age,
and Allard was one--a little more conspicuous than the majority--among many who made experiment in ignorance,
with more or less danger
to themselves and without practical result of any kind.
The seventeenth century was not
to end,
however,
without practical experiment of a noteworthy kind in gliding flight.
Among the recruits
to the ranks of pioneers was a certain Besnier,
a locksmith of Sable,
who somewhere between 1675 and 1680 constructed a glider of which a crude picture has come down
to modern times.
The apparatus,
as will be seen,
consisted of two rods
with hinged flaps,
and the original designer of the picture seems
to have had but a small space in which
to draw,
since obviously the flaps must have been much larger than those shown.
Besnier placed the rods on his shoulders,
and worked the flaps by cords attached
to his hands and feet--the flaps opened as they fell,
and closed as they rose,
so the device as a whole must be regarded as a sort of flapping glider.
Having by experiment proved his apparatus successful,
Besnier promptly sold it
to a travelling showman of the period,
and forthwith set about constructing a second set,
with which he made gliding flights of considerable height and distance.
Like Lilienthal,
Besnier projected himself into space from some height,
and then,
according
to the contemporary records,
he was able
to cross a river of considerable size before coming
to earth.
It does not appear that he had any imitators,
or that any advantage whatever was taken of his experiments;
the age was one in which he would be regarded rather as a freak exhibitor than as a serious student,
and possibly,
considering his origin and the sale of his first apparatus
to such a client,
he regarded the matter himself as more in the nature of an amusement than as a discovery.
Borelli,
coming at the end of the century,
proved
to his own satisfaction and that of his fellows that flapping wing flight was an impossibility;
the capabilities of the plane were as yet undreamed,
and the prime mover that should make the plane available
for flight was deep in the womb of time.
Da Vinci's work was forgotten--flight was an impossibility,
or at best such a useless show as Besnier was able
to give.
The eighteenth century was almost barren of experiment.
Emanuel Swedenborg,
having invented a new religion,
set about inventing a flying machine,
and succeeded theoretically,
publishing the result of his investigations as follows:--
'Let a car or boat or some like object be made of light material such as cork or bark,
with a room within it
for the operator.
Secondly,
in front as well as behind,
or all round,
set a widely-stretched sail parallel
to the machine forming within a hollow or bend which could be reefed like the sails of a ship.
Thirdly,
place wings on the sides,
to be worked up and down by a spiral spring,
these wings also
to be hollow below in order
to increase the force and velocity,
take in the air,
and make the resistance as great as may be required.
These,
too,
should be of light material and of sufficient size;
they should be in the shape of birds'
wings,
or the sails of a windmill,
or some such shape,
and should be tilted obliquely upwards,
and made so as
to collapse on the upward stroke and expand on the downward.
Fourth,
place a balance or beam below,
hanging down perpendicularly
for some distance
with a small weight attached
to its end,
pendent exactly in line
with the centre of gravity;
the longer this beam is,
the lighter must it be,
for it must have the same proportion as the well-known vectis or steel-yard.
This would serve
to restore the balance of the machine if it should lean over
to any of the four sides.
Fifthly,
the wings would perhaps have greater force,
so as
to increase the resistance and make the flight easier,
if a hood or shield were placed over them,
as is the case
with certain insects.
Sixthly,
when the sails are expanded so as
to occupy a great surface and much air,
with a balance keeping them horizontal,
only a small force would be needed
to move the machine back and forth in a circle,
and up and down.
And,
after it has gained momentum
to move slowly upwards,
a slight movement and an even bearing would keep it balanced in the air and would determine its direction at will.'
The only point in this worthy of any note is the first device
for maintaining stability automatically--Swedenborg certainly scored a point there.
For the rest.
his theory was but theory,
incapable of being put
to practice--he does not appear
to have made any attempt at advance beyond the mere suggestion.
Some ten years before his time the state of knowledge
with regard
to flying in Europe was demonstrated by an order granted by the King of Portugal
to Friar Lourenzo de Guzman,
who claimed
to have invented a flying machine capable of actual flight.
The order stated that
'In order
to encourage the suppliant
to apply himself
with zeal toward the improvement of the new machine,
which is capable of producing the effects mentioned by him,
I grant unto him the first vacant place in my College of Barcelos or Santarem,
and the first professorship of mathematics in my University of Coimbra,
with the annual pension of 600,000 reis during his life.--Lisbon,
17th of March,
1709.'
What happened
to Guzman when the non-existence of the machine was discovered is one of the things that is well outside the province of aeronautics.
He was charlatan pure and simple,
as far as actual flight was concerned,
though he had some ideas respecting the design of hot-air balloons,
according
to Tissandier.
(La Navigation Aerienne.)
His flying machine was
to contain,
among other devices,
bellows
to produce artificial wind when the real article failed,
and also magnets in globes
to draw the vessel in an upward direction and maintain its buoyancy.
Some draughtsman,
apparently gifted
with as vivid imagination as Guzman himself,
has given
to the world an illustration of the hypothetical vessel;
it bears some resemblance
to Lana's aerial ship,
from which fact one draws obvious conclusions.
A rather amusing claim
to solving the problem of flight was made in the middle of the eighteenth century by one Grimaldi,
a
'famous and unique Engineer'
who,
as a matter of actual fact,
spent twenty years in missionary work in India,
and employed the spare time that missionary work left him in bringing his invention
to a workable state.
The invention is described as a
'box which
with the aid of clockwork rises in the air,
and goes
with such lightness and strong rapidity that it succeeds in flying a journey of seven leagues in an hour.
It is made in the fashion of a bird;
the wings from end
to end are 25 feet in extent.
The body is composed of cork,
artistically joined together and well fastened
with metal wire,
covered
with parchment and feathers.
The wings are made of catgut and whalebone,
and covered also
with the same parchment and feathers,
and each wing is folded in three seaMs. In the body of the machine are contained thirty wheels of unique work,
with two brass globes and little chains which alternately wind up a counterpoise;
with the aid of six brass vases,
full of a certain quantity of quicksilver,
which run in some pulleys,
the machine is kept by the artist in due equilibrium and balance.
By means,
then,
of the friction between a steel wheel adequately tempered and a very heavy and surprising piece of lodestone,
the whole is kept in a regulated forward movement,
given,
however,
a right state of the winds,
since the machine cannot fly so much in totally calm weather as in stormy.
This prodigious machine is directed and guided by a tail seven palmi long,
which is attached
to the knees and ankles of the inventor by leather straps;
by stretching out his legs,
either
to the right or
to the left,
he moves the machine in whichever direction he pleases....
The machine's flight lasts only three hours,
after which the wings gradually close themselves,
when the inventor,
perceiving this,
goes down gently,
so as
to get on his own feet,
and then winds up the clockwork and gets himself ready again upon the wings
for the continuation of a new flight.
He himself told us that if by chance one of the wheels came off or if one of the wings broke,
it is certain he would inevitably fall rapidly
to the ground,
and,
therefore,
he does not rise more than the height of a tree or two,
as also he only once put himself in the risk of crossing the sea,
and that was from Calais
to Dover,
and the same morning he arrived in London.'
And yet there are still quite a number of people who persist in stating that Bleriot was the first man
to fly across the Channel! A study of the development of the helicopter principle was published in France in 1868,
when the great French engineer Paucton produced his Theorie de la Vis d'Archimede.
For some inexplicable reason,
Paucton was not satisfied
with the term
'helicopter,'
but preferred
to call it a
'pterophore,'
a name which,
so far as can be ascertained,
has not been adopted by any other writer or investigator.
Paucton stated that,
since a man is capable of sufficient force
to overcome the weight of his own body,
it is only necessary
to give him a machine which acts on the air
'with all the force of which it is capable and at its utmost speed,'
and he will then be able
to lift himself in the air,
just as by the exertion of all his strength he is able
to lift himself in water.
'It would seem,'
says Paucton,
'that in the pterophore,
attached vertically
to a carriage,
the whole built lightly and carefully assembled,
he has found something that will give him this result in all perfection.
In construction,
one would be careful that the machine produced the least friction possible,
and naturally it ought
to produce little,
as it would not be at all complicated.
The new Daedalus,
sitting comfortably in his carriage,
would by means of a crank give
to the pterophore a suitable circular
(or revolving)
speed.
This single pterophore would lift him vertically,
but in order
to move horizontally he should be supplied
with a tail in the shape of another pterophore.
When he wished
to stop
for a little time,
valves fixed firmly across the end of the space between the blades would automatically close the openings through which the air flows,
and change the pterophore into an unbroken surface which would resist the flow of air and retard the fall of the machine
to a considerable degree.'
The doctrine thus set forth might appear plausible,
but it is based on the common misconception that all the force which might be put into the helicopter or
'pterophore'
would be utilised
for lifting or propelling the vehicle through the air,
just as a propeller uses all its power
to drive a ship through water.
But,
in applying such a propelling force
to the air,
most of the force is utilised in maintaining aerodynamic support--as a matter of fact,
more force is needed
to maintain this support than the muscle of man could possibly furnish
to a lifting screw,
and even if the helicopter were applied
to a full-sized,
engine-driven air vehicle,
the rate of ascent would depend on the amount of surplus power that could be carried.
For example,
an upward lift of 1,000 pounds from a propeller 15 feet in diameter would demand an expenditure of 50 horse-power under the best possible conditions,
and in order
to lift this load vertically through such atmospheric pressure as exists at sea-level or thereabouts,
an additional 20 horsepower would be required
to attain a rate of 11 feet per second--50 horse-power must be continually provided
for the mere support of the load,
and the additional 20 horse-power must be continually provided in order
to lift it.
Although,
in model form,
there is nothing quite so strikingly successful as the helicopter in the range of flying machines,
yet the essential weight increases so disproportionately
to the effective area that it is necessary
to go but very little beyond model dimensions
for the helicopter
to become quite ineffective.
That is not
to say that the lifting screw must be totally ruled out so far as the construction of aircraft is concerned.
Much is still empirical,
so far as this branch of aeronautics is concerned,
and consideration of the structural features of a propeller goes
to show that the relations of essential weight and effective area do not altogether apply in practice as they stand in theory.
Paucton's dream,
in some modified form,
may yet become reality--it is only so short a time ago as 1896 that Lord Kelvin stated he had not the smallest molecule of faith in aerial navigation,
and since the whole history of flight consists in proving the impossible possible,
the helicopter may yet challenge the propelled plane surface
for aerial supremacy.
It does not appear that Paucton went beyond theory,
nor is there in his theory any advance toward practical flight--da Vinci could have told him as much as he knew.
He was followed by Meerwein,
who invented an apparatus apparently something between a flapping wing machine and a glider,
consisting of two wings,
which were
to be operated by means of a rod;
the venturesome one who would fly by means of this apparatus had
to lie in a horizontal position beneath the wings
to work the rod.
Meerwein deserves a place of mention,
however,
by reason of his investigations into the amount of surface necessary
to support a given weight.
Taking that weight at 200 pounds--which would allow
for the weight of a man and a very light apparatus--he estimated that 126 square feet would be necessary
for support.
His pamphlet,
published at Basle in 1784,
shows him
to have been a painstaking student of the potentialities of flight.
Jean-Pierre Blanchard,
later
to acquire fame in connection
with balloon flight,
conceived and described a curious vehicle,
of which he even announced trials as impending.
His trials were postponed time after time,
and it appears that he became convinced in the end of the futility of his device,
being assisted
to such a conclusion by Lalande,
the astronomer,
who repeated Borelli's statement that it was impossible
for man ever
to fly by his own strength.
This was in the closing days of the French monarchy,
and the ascent of the Montgolfiers'
first hot-air balloon in 1783--which shall be told more fully in its place--put an end
to all French experiments
with heavier- than-air apparatus,
though in England the genius of Cayley was about
to bud,
and even in France there were those who understood that ballooning was not true flight.
III.
SIR GEORGE CAYLEY--THOMAS WALKER On the fifth of June,
1783,
the Montgolfiers'
hot-air balloon rose at Versailles,
and in its rising divided the study of the conquest of the air into two definite parts,
the one being concerned
with the propulsion of gas lifted,
lighter-than-air vehicles,
and the other being crystallised in one sentence by Sir George Cayley:
'The whole problem,'
he stated,
'is confined within these limits,
viz.:
to make a surface support a given weight by the application of power
to the resistance of the air.'
For about ten years the balloon held the field entirely,
being regarded as the only solution of the problem of flight that man could ever compass.
So definite
for a time was this view on the eastern side of the Channel that
for some years practically all the progress that was made in the development of power-driven planes was made in Britain.
In 1800 a certain Dr Thomas Young demonstrated that certain curved surfaces suspended by a thread moved into and not away from a horizontal current of air,
but the demonstration,
which approaches perilously near
to perpetual motion if the current be truly horizontal,
has never been successfully repeated,
so that there is more than a suspicion that Young's air-current was NOT horizontal.
Others had made and were making experiments on the resistance offered
to the air by flat surfaces,
when Cayley came
to study and record,
earning such a place among the pioneers as
to win the title of
'father of British aeronautics.'
Cayley was a man in advance of his time,
in many ways.
Of independent means,
he made the grand tour which was considered necessary
to the education of every young man of position,
and during this excursion he was more engaged in studies of a semi-scientific character than in the pursuits that normally filled such a period.
His various writings prove that throughout his life aeronautics was the foremost subject in his mind;
the Mechanic's Magazine,
Nicholson's Journal,
the Philosophical Magazine,
and other periodicals of like nature bear witness
to Cayley's continued research into the subject of flight.
He approached the subject after the manner of the trained scientist,
analysing the mechanical properties of air under chemical and physical action.
Then he set
to work
to ascertain the power necessary
for aerial flight,
and was one of the first
to enunciate the fallacy of the hopes of successful flight by means of the steam engine of those days,
owing
to the fact that it was impossible
to obtain a given power
with a given weight.
Yet his conclusions on this point were not altogether negative,
for as early as 1810 he stated that he could construct a balloon which could travel
with passengers at 20 miles an hour--he was one of the first
to consider the possibilities of applying power
to a balloon.
Nearly thirty years later--in 1837--he made the first attempt at establishing an aeronautical society,
but at that time the power-driven plane was regarded by the great majority as an absurd dream of more or less mad inventors,
while ballooning ranked on about the same level as tight-rope walking,
being considered an adjunct
to fairs and fetes,
more a pastime than a study.
Up
to the time of his death,
in 1857,
Cayley maintained his study of aeronautical matters,
and there is no doubt whatever that his work went far in assisting the solution of the problem of air conquest.
His principal published work,
a monograph entitled Aerial Navigation,
has been republished in the admirable series of
'Aeronautical Classics'
issued by the Royal Aeronautical Society.
He began this work by pointing out the impossibility of flying by means of attached wings,
an impossibility due
to the fact that,
while the pectoral muscles of a bird account
for more than two-thirds of its whole muscular strength,
in a man the muscles available
for flying,
no matter what mechanism might be used,
would not exceed one-tenth of his total strength.
Cayley did not actually deny the possibility of a man flying by muscular effort,
however,
but stated that
'the flight of a strong man by great muscular exertion,
though a curious and interesting circumstance,
inasmuch as it will probably be the means of ascertaining finis power and supplying the basis whereon
to improve it,
would be of little use.'
From this he goes on
to the possibility of using a Boulton and Watt steam engine
to develop the power necessary
for flight,
and in this he saw a possibility of practical result.
It is worthy of note that in this connection he made mention of the forerunner of the modern internal combustion engine;
'The French,'
he said,
'have lately shown the great power produced by igniting inflammable powders in closed vessels,
and several years ago an engine was made
to work in this country in a similar manner by inflammation of spirit of tar.'
In a subsequent paragraph of his monograph he anticipates almost exactly the construction of the Lenoir gas engine,
which came into being more than fifty-five years after his monograph was published.
Certain experiments detailed in his work were made
to ascertain the size of the surface necessary
for the support of any given weight.
He accepted a truism of to-day in pointing out that in any matters connected
with aerial investigation,
theory and practice are as widely apart as the poles.
Inclined at first
to favour the helicopter principle,
he finally rejected this in favour of the plane,
with which he made numerous experiments.
During these,
he ascertained the peculiar advantages of curved surfaces,
and saw the necessity of providing both vertical and horizontal rudders in order
to admit of side steering as well as the control of ascent and descent,
and
for preserving equilibrium.
He may be said
to have anticipated the work of Lilienthal and Pilcher,
since he constructed and experimented
with a fixed surface glider.
'It was beautiful,'
he wrote concerning this,
'to see this noble white bird sailing majestically from the top of a hill
to any given point of the plain below it
with perfect steadiness and safety,
according
to the set of its rudder,
merely by its own weight,
descending at an angle of about eight degrees
with the horizon.'
It is said that he once persuaded his gardener
to trust himself in this glider
for a flight,
but if Cayley himself ventured a flight in it he has left no record of the fact.
The following extract from his work,
Aerial Navigation,
affords an instance of the thoroughness of his investigations,
and the concluding paragraph also shows his faith in the ultimate triumph of mankind in the matter of aerial flight:--
'The act of flying requires less exertion than from the appearance is supposed.
Not having sufficient data
to ascertain the exact degree of propelling power exerted by birds in the act of flying,
it is uncertain what degree of energy may be required in this respect
for vessels of aerial navigation;
yet when we consider the many hundreds of miles of continued flight exerted by birds of passage,
the idea of its being only a small effort is greatly corroborated.
To apply the power of the first mover
to the greatest advantage in producing this effect is a very material point.
The mode universally adopted by Nature is the oblique waft of the wing.
We have only
to choose between the direct beat overtaking the velocity of the current,
like the oar of a boat,
or one applied like the wing,
in some assigned degree of obliquity
to it.
Suppose 35 feet per second
to be the velocity of an aerial vehicle,
the oar must be moved
with this speed previous
to its being able
to receive any resistance;
then if it be only required
to obtain a pressure of one-tenth of a lb.
upon each square foot it must exceed the velocity of the current 7.3 feet per second.
Hence its whole velocity must be 42.5 feet per second.
Should the same surface be wafted downward like a wing
with the hinder edge inclined upward in an angle of about 50 deg.
40 feet
to the current it will overtake it at a velocity of 3.5 feet per second;
and as a slight unknown angle of resistance generates a lb.
pressure per square foot at this velocity,
probably a waft of a little more than 4 feet per second would produce this effect,
one-tenth part of which would be the propelling power.
The advantage of this mode of application compared
with the former is rather more than ten
to one.
'In continuing the general principles of aerial navigation,
for the practice of the art,
many mechanical difficulties present themselves which require a considerable course of skilfully applied experiments before they can be overcome;
but,
to a certain extent,
the air has already been made navigable,
and no one who has seen the steadiness
with which weights
to the amount of ten stone
(including four stone,
the weight of the machine)
hover in the air can doubt of the ultimate accomplishment of this object.'
This extract from his work gives but a faint idea of the amount of research
for which Cayley was responsible.
He had the humility of the true investigator in scientific problems,
and so far as can be seen was never guilty of the great fault of so many investigators in this subject--that of making claims which he could not support.
He was content
to do,
and pass after having recorded his part,
and although nearly half a century had
to pass between the time of his death and the first actual flight by means of power-driven planes,
yet he may be said
to have contributed very largely
to the solution of the problem,
and his name will always rank high in the roll of the pioneers of flight.
Practically contemporary
with Cayley was Thomas Walker,
concerning whom little is known save that he was a portrait painter of Hull,
where was published his pamphlet on The Art of Flying in 1810,
a second and amplified edition being produced,
also in Hull,
in 1831.
The pamphlet,
which has been reproduced in extenso in the Aeronautical Classics series published by the Royal Aeronautical Society,
displays a curious mixture of the true scientific spirit and colossal conceit.
Walker appears
to have been a man inclined
to jump
to conclusions,
which carried him up
to the edge of discovery and left him vacillating there.
The study of the two editions of his pamphlet side by side shows that their author made considerable advances in the practicability of his designs in the 21 intervening years,
though the drawings which accompany the text in both editions fail
to show anything really capable of flight.
The great point about Walker's work as a whole is its suggestiveness;
he did not hesitate
to state that the
'art'
of flying is as truly mechanical as that of rowing a boat,
and he had some conception of the necessary mechanism,
together
with an absolute conviction that he knew all there was
to be known.
'Encouraged by the public,'
he says,
'I would not abandon my purpose of making still further exertions
to advance and complete an art,
the discovery of the TRUE PRINCIPLES
(the italics are Walker's own)
of which,
I trust,
I can
with certainty affirm
to be my own.'
The pamphlet begins
with Walker's admiration of the mechanism of flight as displayed by birds.
'It is now almost twenty years,'
he says,
'since I was first led
to think,
by the study of birds and their means of flying,
that if an artificial machine were formed
with wings in exact imitation of the mechanism of one of those beautiful living machines,
and applied in the very same way upon the air,
there could be no doubt of its being made
to fly,
for it is an axiom in philosophy that the same cause will ever produce the same effect.'
With this he confesses his inability
to produce the said effect through lack of funds,
though he clothes this delicately in the phrase
'professional avocations and other circumstances.'
Owing
to this inability he published his designs that others might take advantage of them,
prefacing his own researches
with a list of the very early pioneers,
and giving special mention
to Friar Bacon,
Bishop Wilkins,
and the Portuguese friar,
De Guzman.
But,
although he seems
to suggest that others should avail themselves of his theoretical knowledge,
there is a curious incompleteness about the designs accompanying his work,
and about the work itself,
which seems
to suggest that he had more knowledge
to impart than he chose
to make public--or else that he came very near
to complete solution of the problem of flight,
and stayed on the threshold without knowing it.
After a dissertation upon the history and strength of the condor,
and on the differences between the weights of birds,
he says:
'The following observations upon the wonderful difference in the weight of some birds,
with their apparent means of supporting it in their flight,
may tend
to remove some prejudices against my plan from the minds of some of my readers.
The weight of the humming-bird is one drachm,
that of the condor not less than four stone.
Now,
if we reduce four stone into drachms we shall find the condor is 14,336 times as heavy as the humming-bird.
What an amazing disproportion of weight! Yet by the same mechanical use of its wings the condor can overcome the specific gravity of its body
with as much ease as the little humming-bird.
But this is not all.
We are informed that this enormous bird possesses a power in its wings,
so far exceeding what is necessary
for its own conveyance through the air,
that it can take up and fly away
with a whole sheer in its talons,
with as much ease as an eagle would carry off,
in the same manner,
a hare or a rabbit.
This we may readily give credit to,
from the known fact of our little kestrel and the sparrow-hawk frequently flying off
with a partridge,
which is nearly three times the weight of these rapacious little birds.'
After a few more observations he arrives at the following conclusion:
'By attending
to the progressive increase in the weight of birds,
from the delicate little humming-bird up
to the huge condor,
we clearly discover that the addition of a few ounces,
pounds,
or stones,
is no obstacle
to the art of flying;
the specific weight of birds avails nothing,
for by their possessing wings large enough,
and sufficient power
to work them,
they can accomplish the means of flying equally well upon all the various scales and dimensions which we see in nature.
Such being a fact,
in the name of reason and philosophy why shall not man,
with a pair of artificial wings,
large enough,
and
with sufficient power
to strike them upon the air,
be able
to produce the same effect?'
Walker asserted definitely and
with good ground that muscular effort applied without mechanism is insufficient
for human flight,
but he states that if an aeronautical boat were constructed so that a man could sit in it in the same manner as when rowing,
such a man would be able
to bring into play his whole bodily strength
for the purpose of flight,
and at the same time would be able
to get an additional advantage by exerting his strength upon a lever.
At first he concluded there must be expansion of wings large enough
to resist in a sufficient degree the specific gravity of whatever is attached
to them,
but in the second edition of his work he altered this to
'expansion of flat passive surfaces large enough
to reduce the force of gravity so as
to float the machine upon the air
with the man in it.'
The second requisite is strength enough
to strike the wings
with sufficient force
to complete the buoyancy and give a projectile motion
to the machine.
Given these two requisites,
Walker states definitely that flying must be accomplished simply by muscular exertion.
'If we are secure of these two requisites,
and I am very confident we are,
we may calculate upon the success of flight
with as much certainty as upon our walking.'
Walker appears
to have gained some confidence from the experiments of a certain M.
Degen,
a watchmaker of Vienna,
who,
according
to the Monthly Magazine of September,
1809,
invented a machine by means of which a person might raise himself into the air.
The said machine,
according
to the magazine,
was formed of two parachutes which might be folded up or extended at pleasure,
while the person who worked them was placed in the centre.
This account,
however,
was rather misleading,
for the magazine carefully avoided mention of a balloon
to which the inventor fixed his wings or parachutes.
Walker,
knowing nothing of the balloon,
concluded that Degen actually raised himself in the air,
though he is doubtful of the assertion that Degen managed
to fly in various directions,
especially against the wind.
Walker,
after considering Degen and all his works,
proceeds
to detail his own directions
for the construction of a flying machine,
these being as follows:
'Make a car of as light material as possible,
but
with sufficient strength
to support a man in it;
provide a pair of wings about four feet each in length;
let them be horizontally expanded and fastened upon the top edge of each side of the car,
with two joints each,
so as
to admit of a vertical motion
to the wings,
which motion may be effected by a man sitting and working an upright lever in the middle of the car.
Extend in the front of the car a flat surface of silk,
which must be stretched out and kept fixed in a passive state;
there must be the same fixed behind the car;
these two surfaces must be perfectly equal in length and breadth and large enough
to cover a sufficient quantity of air
to support the whole weight as nearly in equilibrium as possible,
thus we shall have a great sustaining power in those passive surfaces and the active wings will propel the car forward.'
A description of how
to launch this car is subsequently given:
'It becomes necessary,'
says the theorist,
'that I should give directions how it may be launched upon the air,
which may be done by various means;
perhaps the following method may be found
to answer as well as any:
Fix a poll upright in the earth,
about twenty feet in height,
with two open collars
to admit another poll
to slide upwards through them;
let there be a sliding platform made fast upon the top of the sliding poll;
place the car
with a man in it upon the platform,
then raise the platform
to the height of about thirty feet by means of the sliding poll,
let the sliding poll and platform suddenly fall down,
the car will then be left upon the air,
and by its pressing the air a projectile force will instantly propel the car forward;
the man in the car must then strike the active wings briskly upon the air,
which will so increase the projectile force as
to become superior
to the force of gravitation,
and if he inclines his weight a little backward,
the projectile impulse will drive the car forward in an ascending direction.
When the car is brought
to a sufficient altitude
to clear the tops of hills,
trees,
buildings,
etc.,
the man,
by sitting a little forward on his seat,
will then bring the wings upon a horizontal plane,
and by continuing the action of the wings he will be impelled forward in that direction.
To descend,
he must desist from striking the wings,
and hold them on a level
with their joints;
the car will then gradually come down,
and when it is within five or six feet of the ground the man must instantly strike the wings downwards,
and sit as far back as he can;
he will by this means check the projectile force,
and cause the car
to alight very gently
with a retrograde motion.
The car,
when up in the air,
may be made
to turn
to the right or
to the left by forcing out one of the fins,
having one about eighteen inches long placed vertically on each side of the car
for that purpose,
or perhaps merely by the man inclining the weight of his body
to one side.'
Having stated how the thing is
to be done,
Walker is careful
to explain that when it is done there will be in it some practical use,
notably in respect of the conveyance of mails and newspapers,
or the saving of life at sea,
or
for exploration,
etc.
It might even reduce the number of horses kept by man
for his use,
by means of which a large amount of land might be set free
for the growth of food
for human consumption.
At the end of his work Walker admits the idea of steam power
for driving a flying machine in place of simple human exertion,
but he,
like Cayley,
saw a drawback
to this in the weight of the necessary engine.
On the whole,
he concluded,
navigation of the air by means of engine power would be mostly confined
to the construction of navigable balloons.
As already noted,
Walker's work is not over practical,
and the foregoing extract includes the most practical part of it;
the rest is a series of dissertations on bird flight,
in which,
evidently,
the portrait painter's observations were far less thorough than those of da Vinci or Borelli.
Taken on the whole,
Walker was a man
with a hobby;
he devoted
to it much time and thought,
but it remained a hobby,
nevertheless.
His observations have proved useful enough
to give him a place among the early students of flight,
but a great drawback
to his work is the lack of practical experiment,
by means of which alone real advance could be made;
for,
as Cayley admitted,
theory and practice are very widely separated in the study of aviation,
and the whole history of flight is a matter of unexpected results arising from scarcely foreseen causes,
together
with experiment as patient as daring.
IV.
THE MIDDLE NINETEENTH CENTURY Both Cayley and Walker were theorists,
though Cayley supported his theoretical work
with enough of practice
to show that he studied along right lines;
a little after his time there came practical men who brought
to being the first machine which actually flew by the application of power.
Before their time,
however,
mention must be made of the work of George Pocock of Bristol,
who,
somewhere about 1840 invented what was described as a
'kite carriage,'
a vehicle which carried a number of persons,
and obtained its motive power from a large kite.
It is on record that,
in the year 1846 one of these carriages conveyed sixteen people from Bristol
to London.
Another device of Pocock's was what he called a
'buoyant sail,'
which was in effect a man-lifting kite,
and by means of which a passenger was actually raised 100 yards from the ground,
while the inventor's son scaled a cliff 200 feet in height by means of one of these,
'buoyant sails.'
This constitutes the first definitely recorded experiment in the use of man-lifting kites.
A History of the Charvolant or Kite-carriage,
published in London in 1851,
states that
'an experiment of a bold and very novel character was made upon an extensive down,
where a large wagon
with a considerable load was drawn along,
whilst this huge machine at the same time carried an observer aloft in the air,
realising almost the romance of flying.'
Experimenting,
two years after the appearance of the
'kite-carriage,'
on the helicopter principle,
W.
H.
Phillips constructed a model machine which weighed two pounds;
this was fitted
with revolving fans,
driven by the combustion of charcoal,
nitre,
and gypsum,
producing steam which,
discharging into the air,
caused the fans
to revolve.
The inventor stated that
'all being arranged,
the steam was up in a few seconds,
when the whole apparatus spun around like any top,
and mounted into the air faster than a bird;
to what height it ascended I had no means of ascertaining;
the distance travelled was across two fields,
where,
after a long search,
I found the machine minus the wings,
which had been torn off in contact
with the ground.'
This could hardly be described as successful flight,
but it was an advance in the construction of machines on the helicopter principle,
and it was the first steam-driven model of the type which actually flew.
The invention,
however,
was not followed up.
After Phillips,
we come
to the great figures of the middle nineteenth century,
W.
S.
Henson and John Stringfellow.
Cayley had shown,
in 1809,
how success might be attained by developing the idea of the plane surface so driven as
to take advantage of the resistance offered by the air,
and Henson,
who as early as 1840 was experimenting
with model gliders and light steam engines,
evolved and patented an idea
for something very nearly resembling the monoplane of the early twentieth century.
His patent,
No.
9478,
of the year 1842 explains the principle of the machine as follows:-- In order that the description hereafter given be rendered clear,
I will first shortly explain the principle on which the machine is constructed.
If any light and flat or nearly flat article be projected or thrown edgewise in a slightly inclined position,
the same will rise on the air till the force exerted is expended,
when the article so thrown or projected will descend;
and it will readily be conceived that,
if the article so projected or thrown possessed in itself a continuous power or force equal
to that used in throwing or projecting it,
the article would continue
to ascend so long as the forward part of the surface was upwards in respect
to the hinder part,
and that such article,
when the power was stopped,
or when the inclination was reversed,
would descend by gravity aided by the force of the power contained in the article,
if the power be continued,
thus imitating the flight of a bird.
Now,
the first part of my invention consists of an apparatus so constructed as
to offer a very extended surface or plane of a light yet strong construction,
which will have the same relation
to the general machine which the extended wings of a bird have
to the body when a bird is skimming in the air;
but in place of the movement or power
for onward progress being obtained by movement of the extended surface or plane,
as is the case
with the wings of birds,
I apply suitable paddle-wheels or other proper mechanical propellers worked by a steam or other sufficiently light engine,
and thus obtain the requisite power
for onward movement
to the plane or extended surface;
and in order
to give control as
to the upward and downward direction of such a machine I apply a tail
to the extended surface which is capable of being inclined or raised,
so that when the power is acting
to propel the machine,
by inclining the tail upwards,
the resistance offered by the air will cause the machine
to rise on the air;
and,
on the contrary,
when the inclination of the tail is reversed,
the machine will immediately be propelled downwards,
and pass through a plane more or less inclined
to the horizon as the inclination of the tail is greater or less;
and in order
to guide the machine as
to the lateral direction which it shall take,
I apply a vertical rudder or second tail,
and,
according as the same is inclined in one direction or the other,
so will be the direction of the machine.'
The machine in question was very large,
and differed very little from the modern monoplane;
the materials were
to be spars of bamboo and hollow wood,
with diagonal wire bracing.
The surface of the planes was
to amount
to 4,500 square feet,
and the tail,
triangular in form
(here modern practice diverges)
was
to be 1,500 square feet.
The inventor estimated that there would be a sustaining power of half a pound per square foot,
and the driving power was
to be supplied by a steam engine of 25
to 30 horse-power,
driving two six-bladed propellers.
Henson was largely dependent on Stringfellow
for many details of his design,
more especially
with regard
to the construction of the engine.
The publication of the patent attracted a great amount of public attention,
and the illustrations in contemporary journals,
representing the machine flying over the pyramids and the Channel,
anticipated fact by sixty years and more;
the scientific world was divided,
as it was up
to the actual accomplishment of flight,
as
to the value of the invention.
Strongfellow and Henson became associated after the conception of their design,
with an attorney named Colombine,
and a Mr Marriott,
and between the four of them a project grew
for putting the whole thing on a commercial basis--Henson and Stringfellow were
to supply the idea;
Marriott,
knowing a member of Parliament,
would be useful in getting a company incorporated,
and Colombine would look after the purely legal side of the business.
Thus an application was made by Mr Roebuck,
Marriott's M.P.,
for an act of incorporation for
'The Aerial Steam Transit Company,'
Roebuck moving
to bring in the bill on the 24th of March,
1843.
The prospectus,
calling
for funds
for the development of the invention,
makes interesting reading at this stage of aeronautical development;
it was as follows:
PROPOSAL.
For subscriptions of sums of L100,
in furtherance of an Extraordinary Invention not at present safe
to be developed by securing the necessary Patents,
for which three times the sum advanced,
namely,
L300,
is conditionally guaranteed
for each subscription on February 1,
1844,
in case of the anticipations being realised,
with the option of the subscribers being shareholders
for the large amount if so desired,
but not otherwise.
--------- An Invention has recently been discovered,
which if ultimately successful will be without parallel even in the age which introduced
to the world the wonderful effects of gas and of steam.
The discovery is of that peculiar nature,
so simple in principle yet so perfect in all the ingredients required
for complete and permanent success,
that
to promulgate it at present would wholly defeat its development by the immense competition which would ensue,
and the views of the originator be entirely frustrated.
This work,
the result of years of labour and study,
presents a wonderful instance of the adaptation of laws long since proved
to the scientific world combined
with established principles so judiciously and carefully arranged,
as
to produce a discovery perfect in all its parts and alike in harmony
with the laws of Nature and of science.
The Invention has been subjected
to several tests and examinations and the results are most satisfactory so much so that nothing but the completion of the undertaking is required
to determine its practical operation,
which being once established its utility is undoubted,
as it would be a necessary possession of every empire,
and it were hardly too much
to say,
of every individual of competent means in the civilised world.
Its qualities and capabilities are so vast that it were impossible and,
even if possible,
unsafe
to develop them further,
but some idea may be formed from the fact that as a preliminary measure patents in Great Britain Ireland,
Scotland,
the Colonies,
France,
Belgium,
and the United States,
and every other country where protection
to the first discoveries of an Invention is granted,
will of necessity be immediately obtained,
and by the time these are perfected,
which it is estimated will be in the month of February,
the Invention will be fit
for Public Trial,
but until the Patents are sealed any further disclosure would be most dangerous
to the principle on which it is based.
Under these circumstances,
it is proposed
to raise an immediate sum of L2,000 in furtherance of the Projector's views,
and as some protection
to the parties who may embark in the matter,
that this is not a visionary plan
for objects imperfectly considered,
Mr Colombine,
to whom the secret has been confided,
has allowed his name
to be used on the occasion,
and who will if referred
to corroborate this statement,
and convince any inquirer of the reasonable prospects of large pecuniary results following the development of the Invention.
It is,
therefore,
intended
to raise the sum of L2,000 in twenty sums of L100 each
(of which any subscriber may take one or more not exceeding five in number
to be held by any individual)
the amount of which is
to be paid into the hands of Mr Colombine as General Manager of the concern
to be by him appropriated in procuring t