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A History of Aeronautics

by E. Charles Vivian

April, 1997  [Etext #874]


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A History of Aeronautics
by E. Charles Vivian




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 man─ásuch 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 the several Patents and providing the expenses
incidental to the works in progress.  For each of which sums of
L100 it is intended and agreed that twelve months after the 1st
February next, the several parties subscribing shall receive as
an equivalent for the risk to be run the sum of L300 for each of
the sums of L100 now subscribed, provided when the time arrives
the Patents shall be found to answer the purposes intended.

As full and complete success is alone looked to, no moderate or
imperfect benefit is to be anticipated, but the work, if it once
passes the necessary ordeal, to which inventions of every kind
must be first subject, will then be regarded by every one as the
most astonishing discovery of modern times; no half success can
follow, and therefore the full nature of the risk is immediately
ascertained.

The intention is to work and prove the Patent by collective
instead of individual aid as less hazardous at first end more
advantageous in the result for the Inventor, as well as others,
by having the interest of several engaged in aiding one common
object--the development of a Great Plan.  The failure is not
feared, yet as perfect success might, by possibility, not ensue,
it is necessary to provide for that result, and the parties
concerned make it a condition that no return of the subscribed
money shall be required, if the Patents shall by any unforeseen
circumstances not be capable of being worked at all; against
which, the first application of the money subscribed, that of
securing the Patents, affords a reasonable security, as no one
without solid grounds would think of such an expenditure.

It is perfectly needless to state that no risk or responsibility
of any kind can arise beyond the payment of the sum to be
subscribed under any circumstances whatever.  

As soon as the Patents shall be perfected and proved it is
contemplated, so far as may be found practicable, to further the
great object in view a Company shall be formed but respecting
which it is unnecessary to state further details, than that a
preference will be given to all those persons who now subscribe,
and to whom shares shall be appropriated according to the larger
amount (being three times the sum to be paid by each person)
contemplated to be returned as soon as the success of the
Invention shall have been established, at their option, or the
money paid, whereby the Subscriber will have the means of either
withdrawing with a large pecuniary benefit, or by continuing his
interest in the concern lay the foundation for participating in
the immense benefit which must follow the success of the plan.

It is not pretended to conceal that the project is a
speculation--all parties believe that perfect success, and
thence incalculable advantage of every kind, will follow to
every individual joining in this great undertaking; but the
Gentlemen engaged in it wish that no concealment of the
consequences, perfect success, or possible failure, should in
the slightest degree be inferred.  They believe this will prove
the germ of a mighty work, and in that belief call for the
operation of others with no visionary object, but a legitimate
one before them, to attain that point where perfect success will
be secured from their combined exertions.

All applications to be made to D. E. Colombine, Esquire, 8
Carlton Chambers, Regent Street.

The applications did not materialise, as was only to be expected
in view of the vagueness of the proposals.  Colombine did some
advertising, and Mr Roebuck expressed himself as unwilling to
proceed further in the venture.  Henson experimented with models
to a certain extent, while Stringfellow looked for funds for the
construction of a full-sized monoplane.  In November of 1843 he
suggested that he and Henson should construct a large model out
of their own funds.  On Henson's suggestion Colombine and
Marriott were bought out as regards the original patent, and
Stringfellow and Henson entered into an agreement and set to
work.

Their work is briefly described in a little pamphlet by F. J.
Stringfellow, entitled A few Remarks on what has been done with
screw-propelled Aero-plane Machines from 1809 to 1892.  The
author writes with regard to the work that his father and Henson
undertook:--

'They commenced the construction of a small model operated by a
spring, and laid down the larger model 20 ft.  from tip to tip
of planes, 3 1/2 ft.  wide, giving 70 ft. of sustaining surface,
about 10 more in the tail.  The making of this model required
great consideration; various supports for the wings were tried,
so as to combine lightness with firmness, strength and rigidity.

'The planes were staid from three sets of fish-shaped masts, and
rigged square and firm by flat steel rigging. The engine and
boiler were put in the car to drive two screw-propellers, right
and left-handed, 3 ft.  in diameter, with four blades each,
occupying three-quarters of the area of the circumference, set
at an angle of 60 degrees.  A considerable time was spent in
perfecting the motive power.  Compressed air was tried and
abandoned. Tappets, cams, and eccentrics were all tried, to work
the slide valve, to obtain the best results.  The piston rod of
engine passed through both ends of the cylinder, and with long
connecting rods worked direct on the crank of the propellers. 
From memorandum of experiments still preserved the following is
a copy of one:  June, 27th, 1845, water 50 ozs., spirit 10 ozs.,
lamp lit 8.45, gauge moves 8.46, engine started 8.48 (100 lb. 
pressure), engine stopped 8.57, worked 9 minutes, 2,288
revolutions, average 254 per minute.  No priming, 40 ozs. water
consumed, propulsion (thrust of propellers), 5 lbs. 4 1/2 ozs. 
at commencement, steady, 4 lbs. 1/2 oz., 57 revolutions to 1 oz.
water, steam cut off one-third from beginning.

'The diameter of cylinder of engine was 1 1/2 inch, length of
stroke 3 inches.

'In the meantime an engine was also made for the smaller model,
and a wing action tried, but with poor results.  The time was
mostly devoted to the larger model, and in 1847 a tent was
erected on Bala Down, about two miles from Chard, and the model
taken up one night by the workmen.  The experiments were not so
favourable as was expected.  The machine could not support
itself for any distance, but, when launched off, gradually
descended, although the power and surface should have been
ample; indeed, according to latest calculations, the thrust
should have carried more than three times the weight, for there
was a thrust of 5 lbs. from the propellers, and a surface of
over 70 square feet to sustain under 30 lbs., but necessary
speed was lacking.'

Stringfellow himself explained the failure as follows:--

'There stood our aerial protegee in all her purity--too
delicate, too fragile, too beautiful for this rough world; at
least those were my ideas at the time, but little did I think
how soon it was to be realised.  I soon found, before I had time
to introduce the spark, a drooping in the wings, a flagging in
all the parts.  In less than ten minutes the machine was
saturated with wet from a deposit of dew, so that anything like
a trial was impossible by night. I did not consider we could get
the silk tight and rigid enough.  Indeed, the framework
altogether was too weak. The steam-engine was the best part. 
Our want of success was not for want of power or sustaining
surface, but for want of proper adaptation of the means to the
end of the various parts.'

Henson, who had spent a considerable amount of money in these
experimental constructions, consoled himself for failure by
venturing into matrimony; in 1849  he went to America, leaving
Stringfellow to continue experimenting alone.  From 1846 to 1848
Stringfellow worked on what is really an epoch-making item in
the history of aeronautics--the first engine-driven aeroplane
which actually flew.  The machine in question had a 10 foot
span, and was 2 ft. across in the widest part of the wing; the
length of tail was 3 ft. 6 ins., and the span of tail in the
widest part 22 ins., the total sustaining area being about 14
sq. ft.  The motive power consisted of an engine with a cylinder
of three-quarter inch diameter and a two-inch stroke; between
this and the crank shaft was a bevelled gear giving three
revolutions of the propellers to every stroke of the engine; the
propellers, right and left screw, were four-bladed and 16 inches
in diameter.  The total weight of the model with engine was 8
lbs.  Its successful flight is ascribed to the fact that
Stringfellow curved the wings, giving them rigid front edges and
flexible trailing edges, as suggested long before both by Da
Vinci and Borelli, but never before put into practice.

Mr F. J. Stringfellow, in the pamphlet quoted above, gives the
best account of the flight of this model:  'My father had
constructed another small model which was finished early in
1848, and having the loan of a long room in a disused lace
factory, early in June the small model was moved there for
experiments.  The room was about 22 yards long and from 10 to 12
ft. high.... The inclined wire for starting the machine occupied
less than half the length of the room and left space at the end
for the machine to clear the floor.  In the first experiment the
tail was set at too high an angle, and the machine rose too
rapidly on leaving the wire.  After going a few yards it slid
back as if coming down an inclined plane, at such an angle that
the point of the tail struck the ground and was broken.  The
tail was repaired and set at a smaller angle.  The steam was
again got up, and the machine started down the wire, and, upon
reaching the point of self-detachment, it gradually rose until
it reached the farther end of the room, striking a hole in the
canvas placed to stop it.  In experiments the machine flew well,
when rising as much as one in seven.  The late Rev. J. Riste,
Esq., lace manufacturer, Northcote Spicer, Esq., J. Toms, Esq.,
and others witnessed experiments. Mr Marriatt, late of the San
Francisco News Letter brought down from London Mr Ellis, the
then lessee of Cremorne Gardens, Mr Partridge, and Lieutenant
Gale, the aeronaut, to witness experiments.  Mr Ellis offered to
construct a covered way at Cremorne for experiments.  Mr
Stringfellow repaired to Cremorne, but not much better
accommodations than he had at home were provided, owing to
unfulfilled engagement as to room.  Mr Stringfellow was
preparing for departure when a party of gentlemen unconnected
with the Gardens begged to see an experiment, and finding them
able to appreciate his endeavours, he got up steam and started
the model down the wire.  When it arrived at the spot where it
should leave the wire it appeared to meet with some obstruction,
and threatened to come to the ground, but it soon recovered
itself and darted off in as fair a flight as it was possible to
make at a distance of about 40 yards, where it was stopped by
the canvas.

'Having now demonstrated the practicability of making a
steam-engine fly, and finding nothing but a pecuniary loss and
little honour, this experimenter rested for a long time,
satisfied with what he had effected.  The subject, however, had
to him special charms, and he still contemplated the renewal of
his experiments.'

It appears that Stringfellow's interest did not revive
sufficiently for the continuance of the experiments until the
founding of the Aeronautical Society of Great Britain in 1866. 
Wenham's paper on Aerial Locomotion read at the first meeting of
the Society, which was held at the Society of Arts under the
Presidency of the Duke of Argyll, was the means of bringing
Stringfellow back into the field.  It was Wenham's suggestion,
in the first place, that monoplane design should be abandoned
for the superposition of planes; acting on this suggestion
Stringfellow constructed a model triplane, and also designed a
steam engine of slightly over one horse-power, and a one
horse-power copper boiler and fire box which, although capable
of sustaining a pressure of 500 lbs. to the square inch, weighed
only about 40 lbs.

Both the engine and the triplane model were exhibited at the
first Aeronautical Exhibition held at the Crystal Palace in
1868.  The triplane had a supporting surface of 28 sq. ft.;
inclusive of engine, boiler, fuel, and water its total weight
was under 12 lbs.  The engine worked two 21 in. propellers at
600 revolutions per minute, and developed 100 lbs. steam
pressure in five minutes, yielding one-third horse-power.  Since
no free flight was allowed in the Exhibition, owing to danger
from fire, the triplane was suspended from a wire in the nave of
the building, and it was noted that, when running along the
wire, the model made a perceptible lift.

A prize of L100 was awarded to the steam engine as the lightest
steam engine in proportion to its power.  The engine and model
together may be reckoned as Stringfellow's best achievement.  He
used his L100  in preparation for further experiments, but he
was now an old man, and his work was practically done.  Both the
triplane and the engine were eventually bought for the
Washington Museum; Stringfellow's earlier models, together with
those constructed by him in conjunction with Henson, remain in
this country in the Victoria and Albert Museum.

John Stringfellow died on December 13th, 1883.  His place in the
history of aeronautics is at least equal to that of Cayley, and
it may be said that he laid the foundation of such work as was
subsequently accomplished by Maxim, Langley, and their fellows. 
It was the coming of the internal combustion engine that
rendered flight practicable, and had this prime mover been
available in John Stringfellow's day the Wright brothers'
achievement might have been antedated by half a century.



V. WENHAM, LE BRIS, AND SOME OTHERS

There are few outstanding events in the development of
aeronautics between Stringfellow's final achievement and the
work of such men as Lilienthal, Pilcher, Montgomery, and their
kind; in spite of this, the later middle decades of the
nineteenth century witnessed a considerable amount of spade work
both in England and in France, the two countries which led in
the way in aeronautical development until Lilienthal gave honour
to Germany, and Langley and Montgomery paved the way for the
Wright Brothers in America.

Two abortive attempts characterised the sixties of last century
in France.  As regards the first of these, it was carried out by
three men, Nadar, Ponton d'Amecourt, and De la Landelle, who
conceived the idea of a full-sized helicopter machine. 
D'Amecourt exhibited a steam model, constructed in 1865, at the
Aeronautical Society's Exhibition in 1868.  The engine was
aluminium with cylinders of bronze, driving two screws placed
one above the other and rotating in Opposite directions, but the
power was not sufficient to lift the model.  De la Landelle's
principal achievement consisted in the publication in 1863 of a
book entitled Aviation which has a certain historical value; he
got out several designs for large machines on the helicopter
principle, but did little more until the three combined in the
attempt to raise funds for the construction of their
full-sized machine.  Since the funds were not forthcoming,
Nadar took to ballooning as the means of raising money;
apparently he found this substitute for real flight sufficiently
interesting to divert him from the study of the helicopter
principle, for the experiment went no further.

The other experimenter of this period, one Count d'Esterno, took
out a patent in 1864 for a soaring machine which allowed for
alteration of the angle of incidence of the wings in the manner
that was subsequently carried out by the Wright Brothers.  It
was not until 1883 that any attempt was made to put this patent
to practical use, and, as the inventor died while it was under
construction, it was never completed.  D'Esterno was also
responsible for the production of a work entitled Du Vol des
Oiseaux, which is a very remarkable study of the flight of
birds.

Mention has already been made of the founding of the
Aeronautical Society of Great Britain, which, since 1918 has
been the Royal Aeronautical Society.  1866 witnessed the first
meeting of the Society under the Presidency of the Duke of
Argyll, when in June, at the Society of Arts, Francis Herbert
Wenham read his now classic paper Aerial Locomotion.  Certain
quotations from this will show how clearly Wenham had thought
out the problems connected with flight.

'The first subject for consideration is the proportion of
surface to weight, and their combined effect in descending
perpendicularly through the atmosphere.  The datum is here based
upon the consideration of safety, for it may sometimes be
needful for a living being to drop passively, without muscular
effort.  One square foot of sustaining surface for every pound
of the total weight will be sufficient for security.

'According to Smeaton's table of atmospheric resistances, to
produce a force of one pound on a square foot, the wind must
move against the plane (or which is the same thing, the plane
against the wind), at the rate of twenty-two feet per second, or
1,320 feet per minute, equal to fifteen miles per hour.  The
resistance of the air will now balance the weight on the
descending surface, and, consequently, it cannot exceed that
speed.  Now, twenty-two feet per second is the velocity acquired
at the end of a fall of eight feet--a height from which a
well-knit man or animal may leap down without much risk of
injury.  Therefore, if a man with parachute weigh together 143
lbs., spreading the same number of square feet of surface
contained in a circle fourteen and a half feet in diameter, he
will descend at perhaps an unpleasant velocity, but with safety
to life and limb.

'It is a remarkable fact how this proportion of wing-surface to
weight extends throughout a great variety of the flying portion
of the animal kingdom, even down to hornets, bees, and other
insects.  In some instances, however, as in the gallinaceous
tribe, including pheasants, this area is somewhat exceeded, but
they are known to be very poor fliers.  Residing as they do
chiefly on the ground, their wings are only required for short
distances, or for raising them or easing their descent from
their roosting-places in forest trees, the shortness of their
wings preventing them from taking extended flights.  The
wing-surface of the common swallow is rather more than in the
ratio of two square feet per pound, but having also great length
of pinion, it is both swift and enduring in its flight.  When on
a rapid course this bird is in the habit of furling its wings
into a narrow compass.  The greater extent of surface is
probably needful for the continual variations of speed and
instant stoppages for obtaining its insect food.

'On the other hand, there are some birds, particularly of the
duck tribe, whose wing-surface but little exceeds half a square
foot, or seventy-two inches per pound, yet they may be classed
among the strongest and swiftest of fliers.  A weight of one
pound, suspended from an area of this extent, would acquire a
velocity due to a fall of sixteen feet--a height sufficient for
the destruction or injury of most animals.  But when the plane
is urged forward horizontally, in a manner analogous to the
wings of a bird during flight, the sustaining power is greatly
influenced by the form and arrangement of the surface.

'In the case of perpendicular descent, as a parachute, the
sustaining effect will be much the same, whatever the figure of
the outline of the superficies may be, and a circle perhaps
affords the best resistance of any.  Take, for example, a circle
of twenty square feet (as possessed by the pelican) loaded with
as many pounds.  This, as just stated, will limit the rate of
perpendicular descent to 1,320 feet per minute.  But instead of
a circle sixty-one inches in diameter, if the area is bounded by
a parallelogram ten feet long by two feet broad, and whilst at
perfect freedom to descend perpendicularly, let a force be
applied exactly in a horizontal direction, so as to carry it
edgeways, with the long side foremost, at a forward speed of
thirty miles per hour--just double that of its passive descent: 
the rate of fall under these conditions will be decreased most
remarkably, probably to less than one-fifteenth part, or
eighty-eight feet per minute, or one mile per hour.'

And again:  'It has before been shown how utterly inadequate the
mere perpendicular impulse of a plane is found to be in
supporting a weight, when there is no horizontal motion at the
time.  There is no material weight of air to be acted upon, and
it yields to the slightest force, however great the velocity of
impulse may be.  On the other hand, suppose that a large bird,
in full flight, can make forty miles per hour, or 3,520 feet per
minute, and performs one stroke per second.  Now, during every
fractional portion of that stroke, the wing is acting upon and
obtaining an impulse from a fresh and undisturbed body of air;
and if the vibration of the wing is limited to an arc of two
feet, this by no means represents the small force of action that
would be obtained when in a stationary position, for the impulse
is secured upon a stratum of fifty-eight feet in length of air
at each stroke. So that the conditions of weight of air for
obtaining support equally well apply to weight of air and its
reaction in producing forward impulse.

'So necessary is the acquirement of this horizontal speed, even
in commencing flight, that most heavy birds, when possible, rise
against the wind, and even run at the top of their speed to make
their wings available, as in the example of the eagle, mentioned
at the commencement of this paper.  It is stated that the Arabs,
on horseback, can approach near enough to spear these birds,
when on the plain, before they are able to rise; their habit is
to perch on an eminence, where possible.

'The tail of a bird is not necessary for flight.  A pigeon can
fly perfectly with this appendage cut short off; it probably
performs an important function in steering, for it is to be
remarked, that most birds that have either to pursue or evade
pursuit are amply provided with this organ.

'The foregoing reasoning is based upon facts, which tend to show
that the flight of the largest and heaviest of all birds is
really performed with but a small amount of force, and that man
is endowed with sufficient muscular power to enable him also to
take individual and extended flights, and that success is
probably only involved in a question of suitable mechanical
adaptations.  But if the wings are to be modelled in imitation
of natural examples, but very little consideration will serve to
demonstrate its utter impracticability when applied in these
forms.'

Thus Wenham, one of the best theorists of his age.  The Society
with which this paper connects his name has done work, between
that time and the present, of which the importance cannot be
overestimated, and has been of the greatest value in the
development of aeronautics, both in theory and experiment.  The
objects of the Society are to give a stronger impulse to the
scientific study of aerial navigation, to promote the
intercourse of those interested in the subject at home and
abroad, and to give advice and instruction to those who study
the principles upon which aeronautical science is based.  From
the date of its foundation the Society has given special study
to dynamic flight, putting this before ballooning.  Its library,
its bureau of advice and information, and its meetings, all
assist in forwarding the study of aeronautics, and its
twenty-three early Annual Reports are of considerable value,
containing as they do a large amount of useful information on
aeronautical subjects, and forming practically the basis of
aeronautical science.

Ante to Wenham, Stringfellow and the French experimenters
already noted, by some years, was Le Bris, a French sea captain,
who appears to have required only a thorough scientific training
to have rendered him of equal moment in the history of gliding
flight with Lilienthal himself.  Le Bris, it appears, watched
the albatross and deduced, from the manner in which it supported
itself in the air, that plane surfaces could be constructed and
arranged to support a man in like manner.  Octave Chanute,
himself a leading exponent of gliding, gives the best
description of Le Bris's experiments in a work, Progress in
Flying Machines, which, although published as recently as I
1894,  is already rare.  Chanute draws from a still rarer book,
namely, De la Landelle's work published in 1884.  Le Bris
himself, quoted by De la Landelle as speaking of his first
visioning of human flight, describes how he killed an albatross,
and then--'I took the wing of the albatross and exposed it to
the breeze; and lo! in spite of me it drew forward into the
wind; notwithstanding my resistance it tended to rise.  Thus I
had discovered the secret of the bird!  I comprehended the whole
mystery of flight.'

This apparently took place while at sea; later on Le Bris,
returning to France, designed and constructed an artificial
albatross of sufficient size to bear his own weight.  The fact
that he followed the bird outline as closely as he did attests
his lack of scientific training for his task, while at the same
time the success of the experiment was proof of his genius.  The
body of his artificial bird, boat-shaped, was 13 1/2 ft. in
length, with a breadth of 4 ft. at the widest part.  The
material was cloth stretched over a wooden framework; in front
was a small mast rigged after the manner of a ship's masts to
which were attached poles and cords with which Le Bris intended
to work the wings.  Each wing was 23 ft. in length, giving a
total supporting surface of nearly 220 sq. ft.; the weight of
the whole apparatus was only 92 pounds.  For steering, both
vertical and horizontal, a hinged tail was provided, and the
leading edge of each wing was made flexible.  In construction
throughout, and especially in that of the wings, Le Bris adhered
as closely as possible to the original albatross.

He designed an ingenious kind of mechanism which he termed
'Rotules,' which by means of two levers gave a rotary motion to
the front edge of the wings, and also permitted of their
adjustment to various angles.  The inventor's idea was to stand
upright in the body of the contrivance, working the levers and
cords with his hands, and with his feet on a pedal by means of
which the steering tail was to be worked.  He anticipated that,
given a strong wind, he could rise into the air after the manner
of an albatross, without any need for flapping his wings, and
the account of his first experiment forms one of the most
interesting incidents in the history of flight.  It is related
in full in Chanute's work, from which the present account is
summarised.

Le Bris made his first experiment on a main road near
Douarnenez, at Trefeuntec.  From his observation of the
albatross Le Bris concluded that it was necessary to get some
initial velocity in order to make the machine rise; consequently
on a Sunday morning, with a breeze of about 12 miles an hour
blowing down the road, he had his albatross placed on a cart and
set off, with a peasant driver, against the wind.  At the outset
the machine was fastened to the cart by a rope running through
the rails on which the machine rested, and secured by a slip
knot on Le Bris's own wrist, so that only a jerk on his part was
necessary to loosen the rope and set the machine free.  On each
side walked an assistant holding the wings, and when a turn of
the road brought the machine full into the wind these men were
instructed to let go, while the driver increased the pace from a
walk to a trot.  Le Bris, by pressure on the levers of the
machine, raised the front edges of his wings slightly; they took
the wind almost instantly to such an extent that the horse,
relieved of a great part of the weight he had been drawing,
turned his trot into a gallop.  Le Bris gave the jerk of the
rope that should have unfastened the slip knot, but a concealed
nail on the cart caught the rope, so that it failed to run.  The
lift of the machine was such, however, that it relieved the
horse of very nearly the weight of the cart and driver, as well
as that of Le Bris and his machine, and in the end the rails of
the cart gave way.  Le Bris rose in the air, the machine
maintaining perfect balance and rising to a height of nearly 300
ft., the total length of the glide being upwards of an eighth of
a mile.  But at the last moment the rope which had originally
fastened the machine to the cart got wound round the driver's
body, so that this unfortunate dangled in the air under Le Bris
and probably assisted in maintaining the balance of the
artificial albatross.  Le Bris, congratulating himself on his
success, was prepared to enjoy just as long a time in the air as
the pressure of the wind would permit, but the howls of the
unfortunate driver at the end of the rope beneath him dispelled
his dreams; by working his levers he altered the angle of the
front wing edges so skilfully as to make a very successful
landing indeed for the driver, who, entirely uninjured,
disentangled himself from the rope as soon as he touched the
ground, and ran off to retrieve his horse and cart.

Apparently his release made a difference in the centre of
gravity, for Le Bris could not manipulate his levers for further
ascent; by skilful manipulation he retarded the descent
sufficiently to escape injury to himself; the machine descended
at an angle, so that one wing, striking the ground in front of
the other, received a certain amount of damage.

It may have been on account of the reluctance of this same or
another driver that Le Bris chose a different method of
launching himself in making a second experiment with his
albatross.  He chose the edge of a quarry which had been
excavated in a depression of the ground; here he assembled his
apparatus at the bottom of the quarry, and by means of a rope
was hoisted to a height of nearly 100 ft. from the quarry
bottom, this rope being attached to a mast which he had erected
upon the edge of the depression in which the quarry was
situated.  Thus hoisted, the albatross was swung to face a
strong breeze that blew inland, and Le Bris manipulated his
levers to give the front edges of his wings a downward angle, so
that only the top surfaces should take the wing pressure. Having
got his balance, he obtained a lifting angle of incidence on the
wings by means of his levers, and released the hook that secured
the machine, gliding off over the quarry.  On the glide he met
with the inevitable upward current of air that the quarry and
the depression in which it was situated caused; this current
upset the balance of the machine and flung it to the bottom of
the quarry, breaking it to fragments.  Le Bris, apparently as
intrepid as ingenious, gripped the mast from which his levers
were worked, and, springing upward as the machine touched earth,
escaped with no more damage than a broken leg.  But for the
rebound of the levers he would have escaped even this.

The interest of these experiments is enhanced by the fact that
Le Bris was a seafaring man who conducted them from love of the
science which had fired his imagination, and in so doing
exhausted his own small means.  It was in 1855 that he made
these initial attempts, and twelve years passed before his
persistence was rewarded by a public subscription made at Brest
for the purpose of enabling him to continue his experiments.  He
built a second albatross, and on the advice of his friends
ballasted it for flight instead of travelling in it himself.  It
was not so successful as the first, probably owing to the lack
of human control while in flight; on one of the trials a height
of 150 ft. was attained, the glider being secured by a thin rope
and held so as to face into the wind.  A glide of nearly an
eighth of a mile was made with the rope hanging slack, and, at
the end of this distance, a rise in the ground modified the
force of the wind, whereupon the machine settled down without
damage.  A further trial in a gusty wind resulted in the
complete destruction of this second machine; Le Bris had no more
funds, no further subscriptions were likely to materialise, and
so the experiments of this first exponent of the art of gliding
(save for Besnier and his kind) came to an end.  They
constituted a notable achievement, and undoubtedly Le Bris
deserves a better place than has been accorded him in the ranks
of the early experimenters.

Contemporary with him was Charles Spencer, the first man to
practice gliding in England.  His apparatus consisted of a pair
of wings with a total area of 30 sq. ft., to which a tail and
body were attached.  The weight of this apparatus was some 24
lbs., and, launching himself on it from a small eminence, as was
done later by Lilienthal in his experiments, the inventor made
flights of over 120 feet.  The glider in question was exhibited
at the Aeronautical Exhibition of 1868.



VI. THE AGE OF THE   GIANTS

Until the Wright Brothers definitely solved the problem of
flight and virtually gave the aeroplane its present place in
aeronautics, there were three definite schools of experiment. 
The first of these was that which sought to imitate nature by
means of the ornithopter or flapping-wing machines directly
imitative of bird flight; the second school was that which
believed in the helicopter or lifting screw; the third and
eventually successful school is that which followed up the
principle enunciated by Cayley, that of opposing a plane surface
to the resistance of the air by supplying suitable motive power
to drive it at the requisite angle for support.

Engineering problems generally go to prove that too close an
imitation of nature in her forms of recipro-cating motion is not
advantageous; it is impossible to copy the minutiae of a bird's
wing effectively, and the bird in flight depends on the tiniest
details of its feathers just as much as on the general principle
on which the whole wing is constructed.  Bird flight, however,
has attracted many experimenters, including even Lilienthal;
among others may be mentioned F. W. Brearey, who invented what
he called the 'Pectoral cord,' which stored energy on each
upstroke of the artificial wing; E. P. Frost; Major R. Moore,
and especially Hureau de Villeneuve, a most enthusiastic student
of this form of flight, who began his experiments about 1865,
and altogether designed and made nearly 300 artificial birds.
one of his later constructions was a machine in bird form with a
wing span of about 50 ft.; the motive power for this was
supplied by steam from a boiler which, being stationary on the
ground, was connected by a length of hose to the machine.  De
Villeneuve, turning on steam for his first trial, obtained
sufficient power to make the wings beat very forcibly; with the
inventor on the machine the latter rose several feet into the
air, whereupon de Villeneuve grew nervous  and turned off the
steam supply.  The machine fell to the earth, breaking one of
its wings, and it does not appear that de Villeneuve troubled to
reconstruct it.  This experiment remains as the greatest success
yet achieved by any machine constructed on the ornithopter
principle.

It may be that, as forecasted by the prophet Wells, the
flapping-wing machine will yet come to its own and compete with
the aeroplane in efficiency.  Against this, however, are the
practical advantages of the rotary mechanism of the aeroplane
propeller as compared with the movement of a bird's wing, which,
according to Marey, moves in a figure of eight.  The force
derived from a propeller is of necessity continual, while it is
equally obvious that that derived from a flapping movement is
intermittent, and, in the recovery of a wing after completion of
one stroke for the next, there is necessarily a certain
cessation, if not loss, of power.

The matter of experiment along any lines in connection with
aviation is primarily one of hard cash. Throughout the whole
history of flight up to the outbreak of the European war
development has been handicapped on the score of finance, and,
since the arrival of the aeroplane, both ornithopter and
helicopter schools have been handicapped by this consideration.
Thus serious study of the efficiency of wings in imitation of
those of the living bird has not been carried to a point that
might win success for this method of propulsion.  Even Wilbur
Wright studied this subject and propounded certain theories,
while a later and possibly more scientific student, F. W.
Lanchester, has also contributed empirical conclusions.  Another
and earlier student was Lawrence Hargrave, who made a
wing-propelled model which achieved successful flight, and in
1885 was exhibited before the Royal Society of New South Wales.
Hargrave called the principle on which his propeller worked that
of a 'Trochoided plane'; it was, in effect, similar to the
feathering of an oar.

Hargrave, to diverge for a brief while from the machine to the
man, was one who, although he achieved nothing worthy of special
remark, contributed a great deal of painstaking work to the
science of flight.  He made a series of experiments with
man-lifting kites in addition to making a study of flapping-wing
flight.  It cannot be said that he set forth any new principle;
his work was mainly imitative, but at the same time by
developing ideas originated in great measure by others he helped
toward the solution of the problem.

Attempts at flight on the helicopter principle consist in the
work of De la Landelle and others already mentioned.  The
possibility of flight by this method is modified by a very
definite disadvantage of which lovers of the helicopter seem to
take little account.  It is always claimed for a machine of this
type that it possesses great advantages both in rising and in
landing, since, if it were effective, it would obviously be able
to rise from and alight on any ground capable of containing its
own bulk; a further advantage claimed is that the helicopter
would be able to remain stationary in the air, maintaining
itself in any position by the vertical lift of its propeller.

These potential assets do not take into consideration the fact
that efficiency is required not only in rising, landing, and
remaining stationary in the air, but also in actual flight.  It
must be evident that if a certain amount of the motive force is
used in maintaining the machine off the ground, that amount of
force is missing from the total of horizontal driving power. 
Again, it is often assumed by advocates of this form of flight
that the rapidity of climb of the helicopter would be far
greater than that of the driven plane; this view overlooks the
fact that the maintenance of aerodynamic support would claim the
greater part of the engine-power; the rate of ascent would be
governed by the amount of power that could be developed surplus
to that required for maintenance.

This is best explained by actual figures:  assuming that a
propeller 15 ft. in diameter is used, almost 50 horse-power
would be required to get an upward lift of 1,000 pounds; this
amount of horse-power would be continually absorbed in
maintaining the machine in the air at any given level; for
actual lift from one level to another at a speed of eleven feet
per second a further 20 horse-power would be required, which
means that 70 horse-power must be constantly provided for; this
absorption of power in the mere maintenance of aero-dynamic
support is a permanent drawback.

The attraction of the helicopter lies, probably, in the ease
with which flight is demonstrated by means of models constructed
on this principle, but one truism with regard to the principles
of flight is that the problems change remarkably, and often
unexpectedly, with the size of the machine constructed for
experiment.  Berriman, in a brief but very interesting manual
entitled Principles of Flight, assumed that 'there is a
significant dimension of which the effective area is an
expression of the second power, while the weight became an
expression of the third power.  Then once again we have the
two-thirds power law militating against the successful
construction of large helicopters, on the ground that the
essential weight increases disproportionately fast to the
effective area.  From a consideration of the structural features
of propellers it is evident that this particular relationship
does not apply in practice, but it seems reasonable that some
such governing factor should exist as an explanation of the
apparent failure of all full-sized machines that have been
constructed.  Among models there is nothing more strikingly
successful than the toy helicopter, in which the essential
weight is so small compared with the effective area.'

De la Landelle's work, already mentioned, was carried on a few
years later by another Frenchman, Castel, who constructed a
machine with eight propellers arranged in two fours and driven
by a compressed air motor or engine.  The model with which
Castel experimented had a total weight of only 49 lbs.; it rose
in the air and smashed itself by driving against a wall, and the
inventor does not seem to have proceeded further. Contemporary
with Castel was Professor Forlanini, whose design was for a
machine very similar to de la Landelle's, with two superposed
screws.  This machine ranks as the second on the helicopter
principle to achieve flight; it remained in the air for no less
than the third of a minute in one of its trials.

Later experimenters in this direction were Kress, a German;
Professor Wellner, an Austrian; and W. R. Kimball, an American. 
Kress, like most Germans, set to the development of an idea
which others had originated; he followed de la Landelle and
Forlanini by fitting two superposed propellers revolving in
opposite directions, and with this machine he achieved good
results as regards horse-power to weight; Kimball, it appears,
did not get beyond the rubber-driven model stage, and any
success he may have achieved was modified by the theory
enunciated by Berriman and quoted above.

Comparing these two schools of thought, the helicopter and
bird-flight schools, it appears that the latter has the greater
chance of eventual success--that is, if either should ever come
into competition with the aeroplane as effective means of
flight.  So far, the aeroplane holds the field, but the whole
science of flight is so new and so full of unexpected
developments that this is no reason for assuming that other
means may not give equal effect, when money and brains are
diverted from the driven plane to a closer imitation of natural
flight.

Reverting from non-success to success, from consideration of the
two methods mentioned above to the direction in which practical
flight has been achieved, it is to be noted that between the
time of Le Bris, Stringfellow, and their contemporaries, and the
nineties of last century, there was much plodding work carried
out with little visible result, more especially so far as
English students were concerned.  Among the incidents of those
years is one of the most pathetic tragedies in the whole history
of aviation, that of Alphonse Penaud, who, in his thirty years
of life, condensed the experience of his predecessors and
combined it with his own genius to state in a published patent
what the aeroplane of to-day should be.  Consider the following
abstract of Penaud's design as published in his patent of 1876,
and comparison of this with the aeroplane that now exists will
show very few divergences except for those forced on the
inventor by the fact that the internal combustion engine had not
then developed.  The double surfaced planes were to be built
with wooden ribs and arranged with a slight dihedral angle;
there was to be a large aspect ratio and the wings were cambered
as in Stringfellow's later models.  Provision was made for
warping the wings while in flight, and the trailing edges were
so designed as to be capable of upward twist while the machine
was in the air.  The planes were to be placed above the car, and
provision was even made for a glass wind-screen to give
protection to the pilot during flight.  Steering was to be
accomplished by means of lateral and vertical planes forming a
tail; these controlled by a single lever corresponding to the
'joy stick' of the present day plane.

Penaud conceived this machine as driven by two propellers;
alternatively these could be driven by petrol or steam-fed
motor, and the centre of gravity of the machine while in flight
was in the front fifth of the wings. Penaud estimated from 20 to
30 horse-power sufficient to drive this machine, weighing with
pilot and passenger 2,600 lbs., through the air at a speed of 60
miles an hour, with the wings set at an angle of  incidence of
two degrees.  So complete was the design that it even included
instruments, consisting of an aneroid, pressure indicator, an
anemometer, a compass, and a level.  There, with few
alterations, is the aeroplane as we know it--and Penaud was
twenty-seven when his patent was published.

For three years longer he worked, experimenting with models,
contributing essays and other valuable data to French papers on
the subject of aeronautics.  His gains were ill health, poverty,
and neglect, and at the age of thirty a pistol shot put an end
to what had promised to be one of the most brilliant careers in
all the history of flight.

Two years before the publication of Penaud's patent Thomas Moy
experimented at the Crystal Palace with a twin-propelled
aeroplane, steam driven, which seems to have failed mainly
because the internal combustion engine had not yet come to give
sufficient power for weight.  Moy anchored his machine to a pole
running on a prepared circular track; his engine weighed 80 lbs. 
and, developing only three horse-power, gave him a speed of
12 miles an hour.  He himself estimated that the machine would
not rise until he could get a speed of 35 miles an hour, and his
estimate was correct.  Two six-bladed propellers were placed
side by side between the two main planes of the machine, which
was supported on a triangular wheeled undercarriage and steered
by fairly conventional tail planes.  Moy realised that he could
not get sufficient power to achieve flight, but he went on
experimenting in various directions, and left much data
concerning his experiments which has not yet been deemed worthy
of publication, but which still contains a mass of information
that is of practical utility, embodying as it does a vast amount
of painstaking work.

Penaud and Moy were followed by Goupil, a Frenchman, who, in
place of attempting to fit a motor to an aeroplane, experimented
by making the wind his motor.  He anchored his machine to the
ground, allowing it two feet of lift, and merely waited for a
wind to come along and lift it.  The machine was stream lined,
and the wings, curving as in the early German patterns of war
aeroplanes, gave a total lifting surface of about 290 sq. ft.
Anchored to the ground and facing a wind of 19 feet per second,
Goupil's machine lifted its own weight and that of two men as
well to the limit of its anchorage.  Although this took place as
late as 1883 the inventor went no further in practical work.  He
published a book, however, entitled La Locomotion Aerienne,
which is still of great importance, more especially on the
subject of inherent stability.

In 1884 came the first patents of Horatio Phillips, whose work
lay mainly in the direction of investigation into the curvature
of plane surfaces, with a view to obtaining the greatest amount
of support.  Phillips was one of the first to treat the problem
of curvature of planes as a matter for scientific experiment,
and, great as has been the development of the driven plane in
the 36 years that have passed since he began, there is still
room for investigation into the subject which he studied so
persistently and with such valuable result.

At this point it may be noted that, with the solitary exception
of Le Bris, practically every student of flight had so far set
about constructing the means of launching humanity into the air
without any attempt at ascertaining the nature and peculiarities
of the sustaining medium.  The attitude of experimenters in
general might be compared to that of a man who from boyhood had
grown up away from open water, and, at the first sight of an
expanse of water, set to work to construct a boat with a vague
idea that, since wood would float, only sufficient power was
required to make him an efficient navigator.  Accident, perhaps,
in the shape of lack of means of procuring driving power, drove
Le Bris to the form of experiment which he actually carried out;
it remained for the later years of the nineteenth century to
produce men who were content to ascertain the nature of the
support the air would afford before attempting to drive
themselves through it.

Of the age in which these men lived and worked, giving their all
in many cases to the science they loved, even to life itself, it
may be said with truth that 'there were giants on the earth in
those days,' as far as aeronautics is in question.  It was an
age of giants who lived and dared and died, venturing into
uncharted space, knowing nothing of its dangers, giving, as a
man gives to his mistress, without stint and for the joy of the
giving.  The science of to-day, compared with the glimmerings
that were in that age of the giants, is a fixed and certain
thing; the problems of to-day are minor problems, for the great
major problem vanished in solution when the Wright Brothers made
their first ascent.  In that age of the giants was evolved the
flying man, the new type in human species which found full
expression and came to full development in the days of the war,
achieving feats of daring and endurance which leave the
commonplace landsman staggered at thought of that of which his
fellows prove themselves capable.  He is a new type, this flying
man, a being of self-forgetfulness; of such was Lilienthal, of
such was Pilcher; of such in later days were Farman, Bleriot,
Hamel, Rolls, and their fellows; great names that will live for
as long as man flies, adventurers equally with those of the
spacious days of Elizabeth.  To each of these came the call, and
he worked and dared and passed, having, perhaps, advanced one
little step in the long march that has led toward the perfecting
of flight.

It is not yet twenty years since man first flew, but into that
twenty years have been compressed a century or so of progress,
while, in the two decades that preceded it, was compressed still
more.  We have only to recall and recount the work of four men: 
Lilienthal, Langley, Pilcher, and Clement Ader to see the
immense stride that was made between the time when Penaud pulled
a trigger for the last time and the Wright Brothers first left
the earth.  Into those two decades was compressed the
investigation that meant knowledge of the qualities of the air,
together with the development of the one prime mover that
rendered flight a possibility--the internal combustion engine. 
The coming and progress of this latter is a thing apart, to be
detailed separately; for the present we are concerned with the
evolution of the driven plane, and with it the evolution of that
daring being, the flying man.  The two are inseparable, for the
men gave themselves to their art; the story of Lilienthal's life
and death is the story of his work; the story of Pilcher's work
is that of his life and death.

Considering the flying man as he appeared in the war period,
there entered into his composition a new element--patriotism--
which brought about a modification of the type, or, perhaps, made
it appear that certain men belonged to the type who in reality
were commonplace mortals, animated, under normal conditions, by
normal motives, but driven by the stress of the time to take rank
with the last expression of human energy, the flying type. 
However that may be, what may be termed the mathematising of
aeronautics has rendered the type itself evanescent; your pilot
of to-day knows his craft, once he is trained, much in the manner
that a driver of a motor-lorry knows his vehicle; design has been
systematised, capabilities have been tabulated; camber, dihedral
angle, aspect ratio, engine power, and plane surface, are
business items of drawing office and machine shop; there is room
for enterprise, for genius, and for skill; once and again there
is room for daring, as in the first Atlantic flight.  Yet that
again was a thing of mathematical calculation and petrol storage,
allied to a certain stark courage which may be found even in
landsmen.  For the ventures into the unknown, the limit of
daring, the work for work's sake, with the almost certainty that
the final reward was death, we must look back to the age of the
giants, the age when flying was not a business, but romance.



VII. LILIENTHAL AND  PILCHER

There was never a more enthusiastic and consistent student of
the problems of flight than Otto Lilienthal, who was born in
1848 at Anklam, Pomerania, and even from his early school-days
dreamed and planned the conquest of the air.  His practical
experiments began when, at the age of thirteen, he and his
brother Gustav made wings consisting of wooden framework covered
with linen, which Otto attached to his arms, and then ran
downhill flapping them.  In consequence of possible derision on
the part of other boys, Otto confined these experiments for the
most part to moonlit nights, and gained from them some idea of
the resistance offered by flat surfaces to the air.  It was in
1867 that the two brothers began really practical work,
experimenting with wings which, from their design, indicate some
knowledge of Besnier and the history of his gliding experiments;
these wings the brothers fastened to their backs, moving them
with their legs after the fashion of one attempting to swim. 
Before they had achieved any real success in gliding the
Franco-German war came as an interruption; both brothers served
in this campaign, resuming their experiments in 1871 at the
conclusion of hostilities.

The experiments made by the brothers previous to the war had
convinced Otto that previous experimenters in gliding flight had
failed through reliance on empirical conclusions or else through
incomplete observation on their own part, mostly of bird flight. 
From 1871 onward Otto Lilenthal (Gustav's interest in the
problem was not maintained as was his brother's) made what is
probably the most detailed and accurate series of observations
that has ever been made with regard to the properties of curved
wing surfaces.  So far as could be done, Lilienthal tabulated
the amount of air resistance offered to a bird's wing,
ascertaining that the curve is necessary to flight, as offering
far more resistance than a flat surface.  Cayley, and others,
had already stated this, but to Lilienthal belongs the honour of
being first to put the statement to effective proof--he made
over 2,000 gliding flights between 1891 and the regrettable end
of his experiments; his practical conclusions are still regarded
as part of the accepted theory of students of flight.  In 1889
he published a work on the subject of gliding flight which
stands as data for investigators, and, on the conclusions
embodied in this work, he began to build his gliders and
practice what he had preached, turning from experiment with
models to wings that he could use.

It was in the summer of 1891 that he built his first glider of
rods of peeled willow, over which was stretched strong cotton
fabric; with this, which had a supporting surface of about 100
square feet, Otto Lilienthal launched himself in the air from a
spring board, making glides which, at first of only a few feet,
gradually lengthened.  As his experience of the supporting
qualities of the air progressed he gradually altered his designs
until, when Pilcher visited him in the spring of 1895, he
experimented with a glider, roughly made of peeled willow rods
and cotton fabric, having an area of 150 square feet and
weighing half a hundredweight.  By this time Lilienthal had
moved from his springboard to a conical artificial hill which he
had had thrown up on level ground at Grosse Lichterfelde, near
Berlin.  This hill was made with earth taken from the
excavations incurred in constructing a canal, and had a cave
inside in which Lilienthal stored his machines.  Pilcher, in his
paper on 'Gliding,' [*] gives an excellent short summary of
Lilienthal's experiments, from which the following extracts are
taken:--

[*] Aeronautical Classes, No. 5.  Royal Aeronautical Society's
publications. 

'At first Lilienthal used to experiment by jumping off a
springboard with a good run.  Then he took to practicing on some
hills close to Berlin.  In the summer of 1892 he built a
flat-roofed hut on the summit of a hill, from the top of which
he used to jump, trying, of course, to soar as far as possible
before landing.... One of the great dangers with a soaring
machine is losing forward speed, inclining the machine too much
down in front, and coming down head first.  Lilienthal was the
first to introduce the system of handling a machine in the air
merely by moving his weight about in the machine; he always
rested only on his elbows or on his elbows and shoulders....

'In 1892 a canal was being cut, close to where Lilienthal lived,
in the suburbs of Berlin, and with the surplus earth Lilienthal
had a special hill thrown up to fly from.  The country round is
as flat as the sea, and there is not a house or tree near it to
make the wind unsteady, so this was an ideal practicing ground;
for practicing on natural hills is generally rendered very
difficult by shifty and gusty winds.... This hill is 50 feet
high, and conical.  Inside the hill there is a cave for the
machines to be kept in.... When Lilienthal made a good flight he
used to land 300 feet from the centre of the hill, having come
down at an angle of 1 in 6; but his best flights have been at an
angle of about 1 in 10.

'If it is calm, one must run a few steps down the hill, holding
the machine as far back on oneself as possible, when the air
will gradually support one, and one slides off the hill into the
air.  If there is any wind, one should face it at starting; to
try to start with a side wind is most unpleasant.  It is
possible after a great deal of practice to turn in the air, and
fairly quickly.  This is accomplished by throwing one's weight
to one side, and thus lowering the machine on that side towards
which one wants to turn. Birds do the same thing-- crows and
gulls show it very clearly.  Last year Lilienthal chiefly
experimented with double-surfaced machines.  These were very
much like the old machines with awnings spread above them.

'The object of making these double-surfaced machines was to get
more surface without increasing the length and width of the
machine.  This, of course, it does, but I personally object to
any machine in which the wing surface is high above the weight. 
I consider that it makes the machine very difficult to handle in
bad weather, as a puff of wind striking the surface, high above
one, has a great tendency to heel the machine over.

'Herr Lilienthal kindly allowed me to sail down his hill in one
of these double-surfaced machines last June. With the great
facility afforded by his conical hill the machine was handy
enough; but I am afraid I should not be able to manage one at
all in the squally districts I have had to practice in over
here.

'Herr Lilienthal came to grief through deserting his old method
of balancing.  In order to control his tipping movements more
rapidly he attached a line from his horizontal rudder to his
head, so that when he moved his head forward it would lift the
rudder and tip the machine up in front, and vice versa.  He was
practicing this on some natural hills outside Berlin, and he
apparently got muddled with the two motions, and, in trying to
regain speed after he had, through a lull in the wind, come to
rest in the air, let the machine get too far down in front, came
down head first and was killed.'

Then in another passage Pilcher enunciates what is the true
value of such experiments as Lilienthal--and, subsequently, he
himself--made:  'The object of experimenting with soaring
machines,' he says, 'is to enable one to have practice in
starting and alighting and controlling a machine in the air. 
They cannot possibly float horizontally in the air for any
length of time, but to keep going must necessarily lose in
elevation.  They are excellent schooling machines, and that is
all they are meant to be, until power, in the shape of an engine
working a screw propeller, or an engine working wings to drive
the machine forward, is added; then a person who is used to
soaring down a hill with a simple soaring machine will be able
to fly with comparative safety.  One can best compare them to
bicycles having no cranks, but on which one could learn to
balance by coming down an incline.'

It was in 1895 that Lilienthal passed from experiment with the
monoplane type of glider to the construction of a biplane glider
which, according to his own account, gave better results than
his previous machines.  'Six or seven metres velocity of wind,'
he says, 'sufficed to enable the sailing surface of 18 square
metres to carry me almost horizontally against the wind from the
top of my hill without any starting jump.  If the wind is
stronger I allow myself to be simply lifted from the point of
the hill and to sail slowly towards the wind.  The direction of
the flight has, with strong wind, a strong upwards tendency.  I
often reach positions in the air which are much higher than my
starting point.  At the climax of such a line of flight I
sometimes come to a standstill for some time, so that I am
enabled while floating to speak with the gentlemen who wish to
photograph me, regarding the best position for the
photographing.'

Lilienthal's work did not end with simple gliding, though he did
not live to achieve machine-driven flight.  Having, as he
considered, gained sufficient experience with gliders, he
constructed a power-driven machine which weighed altogether
about 90 lbs., and this was thoroughly tested.  The extremities
of its wings were made to flap, and the driving power was
obtained from a cylinder of compressed carbonic acid gas,
released through a hand-operated valve which, Lilienthal
anticipated, would keep the machine in the air for four minutes. 
There were certain minor accidents to the mechanism, which
delayed the trial flights, and on the day that Lilienthal had
determined to make his trial he made a long gliding flight with
a view to testing a new form of rudder that--as Pilcher
relates--was worked by movements of his head.  His death came
about through the causes that Pilcher states; he fell from a
height of 50 feet, breaking his spine, and the next day he died.

It may be said that Lilienthal accomplished as much as any one
of the great pioneers of flying.  As brilliant in his
conceptions as da Vinci had been in his, and as conscientious a
worker as Borelli, he laid the foundations on which Pilcher,
Chanute, and Professor Montgomery were able to build to such
good purpose.  His book on bird flight, published in 1889, with
the authorship credited both to Otto and his brother Gustav, is
regarded as epoch-making; his gliding experiments are no less
entitled to this description.

In England Lilienthal's work was carried on by Percy Sinclair
Pilcher, who, born in 1866, completed six years' service in the
British Navy by the time that he was nineteen, and then went
through a course of engineering, subsequently joining Maxim in
his experimental work.  It was not until 1895 that he began
to build the first of the series of gliders with which he earned
his plane among the pioneers of flight.  Probably the best
account of Pilcher's work is that given in the Aeronautical
Classics issued by the Royal Aeronautical Society, from which
the following account of Pilcher's work is mainly abstracted.[*]

[*] Aeronautical Classes, No. 5. Royal  Aeronautical Society
publications. 

The 'Bat,' as Pilcher named his first glider, was a monoplane
which he completed before he paid his visit to Lilienthal in
1895.  Concerning this Pilcher stated that he purposely finished
his own machine before going to see Lilienthal, so as to get the
greatest advantage from any original ideas he might have; he was
not able to make any trials with this machine, however, until
after witnessing Lilienthal's experiments and making several
glides in the biplane glider which Lilienthal constructed.


The wings of the 'Bat' formed a pronounced dihedral angle; the
tips being raised 4 feet above the body.  The spars forming the
entering edges of the wings crossed each other in the centre and
were lashed to opposite sides of the triangle that served as a
mast for the stay-wires that guyed the wings.  The four ribs of
each wing, enclosed in pockets in the fabric, radiated fanwise
from the centre, and were each stayed by three steel piano-wires
to the top of the triangular mast, and similarly to its base. 
These ribs were bolted down to the triangle at their roots, and
could be easily folded back on to the body when the glider was
not in use.  A small fixed vertical surface was carried in the
rear.  The framework and ribs were made entirely of Riga pine;
the surface fabric was nainsook.  The area of the machine was
150 square feet; its weight 45 lbs.; so that in flight, with
Pilcher's weight of 145 lbs. added, it carried one and a half
pounds to the square foot.

Pilcher's first glides, which he carried out on a grass hill on
the banks of the Clyde near Cardross, gave little result, owing
to the exaggerated dihedral angle of the wings, and the absence
of a horizontal tail.  The 'Bat 'was consequently reconstructed
with a horizontal tail plane added to the vertical one, and with
the wings lowered so that the tips were only six inches above
the level of the body.  The machine now gave far better results;
on the first glide into a head wind Pilcher rose to a height of
twelve feet and remained in the the air for a third of a minute;
in the second attempt a rope was used to tow the glider, which
rose to twenty feet and did not come to earth again until nearly
a minute had passed.  With experience Pilcher was able to
lengthen his glide and improve his balance, but the dropped wing
tips made landing difficult, and there were many breakages.

In consequence of this Pilcher built a second glider which he
named the 'Beetle,' because, as he said, it looked like one.  In
this the square-cut wings formed almost a continuous plane,
rigidly fixed to the central body, which consisted of a shaped
girder.  These wings were built up of five transverse bamboo
spars, with two shaped ribs running from fore to aft of each
wing, and were stayed overhead to a couple of masts.  The tail,
consisting of two discs placed crosswise (the horizontal one
alone being movable), was carried high up in the rear. With the
exception of the wing-spars, the whole framework was built of
white pine.  The wings in this machine were actually on a higher
level than the operator's head; the centre of gravity was,
consequently, very low, a fact which, according to Pilcher's own
account, made the glider very difficult to handle. Moreover, the
weight of the 'Beetle,' 80 lbs., was considerable; the body had
been very solidly built to enable it to carry the engine which
Pilcher was then contemplating; so that the glider carried some
225 lbs.  with its area of 170 square feet--too great a mass for
a single man to handle with comfort.

It was in the spring of 1896 that Pilcher built his third
glider, the 'Gull,' with 300 square feet of area and a weight of
55 lbs.  The size of this machine rendered it unsuitable for
experiment in any but very calm weather, and it incurred such
damage when experiments were made in a breeze that Pilcher found
it necessary to build a fourth, which he named the 'Hawk.'  This
machine was very soundly built, being constructed of bamboo,
with the exception of the two main transverse beams.  The wings
were attached to two vertical masts, 7 feet high, and 8 feet
apart, joined at their summits and their centres by two wooden
beams.  Each wing had nine bamboo ribs, radiating from its mast,
which was situated at a distance of 2 feet 6 inches from the
forward edge of the wing.  Each rib was rigidly stayed at the
top of the mast by three tie-wires, and by a similar number to
the bottom of the mast, by which means the curve of each wing
was maintained uniformly.  The tail was formed of a triangular
horizontal surface to which was affixed a triangular vertical
surface, and was carried from the body on a high bamboo mast,
which was also stayed from the masts by means of steel wires,
but only on its upper surface, and it was the snapping of one of
these guy wires which caused the collapse of the tail support
and brought about the fatal end of Pilcher's experiments.  In
flight, Pilcher's head, shoulders, and the greater part of his
chest projected above the wings.  He took up his position by
passing his head and shoulders through the top aperture formed
between the two wings, and resting his forearms on the
longitudinal body members.  A very simple form of undercarriage,
which took the weight off the glider on the ground, was fitted,
consisting of two bamboo rods with wheels suspended on steel
springs.

Balance and steering were effected, apart from the high degree
of inherent stability afforded by the tail, as in the case of
Lilienthal's glider, by altering the position of the body.  With
this machine Pilcher made some twelve glides at Eynsford in Kent
in the summer of 1896, and as he progressed he increased the
length of his glides, and also handled the machine more easily,
both in the air and in landing.  He was occupied with plans for
fitting an engine and propeller to the 'Hawk,' but, in these
early days of the internal combustion engine, was unable to get
one light enough for his purpose.  There were rumours of an
engine weighing 15 lbs.  which gave 1 horse-power, and was
reported to be in existence in America, but it could not be
traced.

In the spring of 1897 Pilcher took up his gliding experiments
again, obtaining what was probably the best of his glides on
June 19th, when he alighted after a perfectly balanced glide of
over 250 yards in length, having crossed a valley at a
considerable height.  From his various experiments he concluded
that once the machine was launched in the air an engine of, at
most, 3 horse-power would suffice for the maintenance of
horizontal flight, but he had to allow for the additional weight
of the engine and propeller, and taking into account the
comparative inefficiency of the propeller, he planned for an
engine of 4 horse-power.  Engine and propeller together were
estimated at under 44 lbs. weight, the engine was to be fitted
in front of the operator, and by means of an overhead shaft was
to operate the propeller situated in rear of the wings.  1898
went by while this engine was under construction.  Then in 1899
Pilcher became interested in Lawrence Hargrave's soaring kites,
with which he carried out experiments during the summer of 1899. 
It is believed that he intended to incorporate a number of these
kites in a new machine, a triplane, of which the fragments
remaining are hardly sufficient to reconstitute the complete
glider.  This new machine was never given a trial.  For on
September 30th, 1899, at Stamford Hall, Market Harborough,
Pilcher agreed to give a demonstration of gliding flight, but
owing to the unfavourable weather he decided to postpone the
trial of the new machine and to experiment with the 'Hawk,'
which was intended to rise from a level field, towed by a line
passing over a tackle drawn by two horses.  At the first trial
the machine rose easily, but the tow-line snapped when it was
well clear of the ground, and the glider descended, weighed down
through being sodden with rain.  Pilcher resolved on a second
trial, in which the glider again rose easily to about thirty
feet, when one of the guy wires of the tail broke, and the tail
collapsed; the machine fell to the ground, turning over, and
Pilcher was unconscious when he was freed from the wreckage.

Hopes were entertained of his recovery, but he died on Monday,
October 2nd, 1899, aged only thirty-four.  His work in the cause
of flying lasted only four years, but in that time his actual
accomplishments were sufficient to place his name beside that of
Lilienthal, with whom he ranks as one of the greatest exponents
of gliding flight.



VIII. AMERICAN GLIDING EXPERIMENTS

While Pilcher was carrying on Lilienthal's work in England, the
great German had also a follower in America; one Octave Chanute,
who, in one of the statements which he has left on the subject
of his experiments acknowledges forty years' interest in the
problem of flight, did more to develop the glider in America
than--with the possible exception of Montgomery--any other man. 
Chanute had all the practicality of an American; he began his
work, so far as actual gliding was concerned, with a full-sized
glider of the Lilienthal type, just before Lilienthal  was
killed. In a rather rare monograph, entitled Experiments in
Flying, Chanute states that he found the Lilienthal glider
hazardous and decided to test the value of an idea of his own;
in this he followed the same general method, but reversed the
principle upon which Lilienthal had depended for maintaining his
equilibrium in the air.  Lilienthal had shifted the weight of
his body, under immovable wings, as fast and as far as the
sustaining pressure varied under his surfaces; this shifting was
mainly done by moving the feet, as the actions required were
small except when alighting.  Chanute's idea was to have the
operator remain seated in the machine in the air, and to
intervene only to steer or to alight; moving mechanism was
provided to adjust the wings automatically in order to restore
balance when necessary.

Chanute realised that experiments with models were of little
use; in order to be fully instructive, these experiments should
be made with a full-sized machine which carried its operator,
for models seldom fly twice alike in the open air, and no
relation can be gained from them of the divergent air currents
which they have experienced.  Chanute's idea was that any flying
machine which might be constructed must be able to operate in a
wind; hence the necessity for an operator to report upon what
occurred in flight, and to acquire practical experience of the
work of the human factor in imitation of bird flight.  From this
point of view he conducted his own experiments; it must be noted
that he was over sixty years of age when he began, and, being no
longer sufficiently young and active to perform any but short
and insignificant glides, the courage of the man becomes all the
more noteworthy; he set to work to evolve the state required by
the problem of stability, and without any expectation of
advancing to the construction of a flying machine which might be
of commercial value.  His main idea was the testing of devices
to secure equilibrium; for this purpose he employed assistants
to carry out the practical work, where he himself was unable to
supply the necessary physical energy.

Together with his assistants he found a suitable place for
experiments among the sandhills on the shore of Lake Michigan,
about thirty miles eastward from Chicago.  Here a hill about
ninety-five feet high was selected as a point from which
Chanute's gliders could set off; in practice, it was found that
the best observation was to be obtained from short glides at
low speed, and, consequently, a hill which was only sixty-one
feet above the shore of the lake was employed for the
experimental work done by the party.

In the years 1896 and 1897, with parties of from four to six
persons, five full-sized gliders were tried out, and from these
two distinct types were evolved:  of these one was a machine
consisting of five tiers of wings and a steering tail, and the
other was of the biplane type; Chanute believed these to be
safer than any other machine previously evolved, solving, as he
states in his monograph, the problem of inherent equilibrium as
fully as this could be done.  Unfortunately, very few
photographs were taken of the work in the first year, but one
view of a multiple wing-glider survives, showing the machine in
flight.  In 1897 a series of photographs was taken exhibiting
the consecutive phases of a single flight; this series of
photographs represents the experience gained in a total of about
one thousand glides, but the point of view was varied so as to
exhibit the consecutive phases of one single flight.

The experience gained is best told in Chanute's own words.  'The
first thing,' he says, 'which we discovered practically was that
the wind flowing up a hill-side is not a steadily-flowing
current like that of a river.  It comes as a rolling mass, full
of tumultuous whirls and eddies, like those issuing from a
chimney; and they strike the apparatus with constantly varying
force and direction, sometimes withdrawing support when most
needed.  It has long been known, through instrumental
observations, that the wind is constantly changing in force and
direction; but it needed the experience of an operator afloat on
a gliding machine to realise that this all proceeded from
cyclonic action; so that more was learned in this respect in a
week than had previously been acquired by several years of
experiments with models.  There was a pair of eagles, living in
the top of a dead tree about two miles from our tent, that came
almost daily to show us how such wind effects are overcome and
utilised.  The birds swept in circles overhead on pulseless
wings, and rose high up in the air.  Occasionally there was a
side-rocking motion, as of a ship rolling at sea, and then the
birds rocked back to an even keel; but although we thought the
action was clearly automatic, and were willing to learn, our
teachers were too far off to show us just how it was done, and
we had to experiment for ourselves.'

Chanute provided his multiple glider with a seat, but, since
each glide only occupied between eight and twelve seconds, there
was little possibility of the operator seating himself.  With
the multiple glider a pair of horizontal bars provided rest for
the arms, and beyond these was a pair of vertical bars which the
operator grasped with his hands; beyond this, the operator was
in no way attached to the machine.  He took, at the most, four
running steps into the wind, which launched him in the air, and
thereupon he sailed into the wind on a generally descending
course.  In the matter of descent Chanute observed the sparrow
and decided to imitate it.  'When the latter,' he says,
'approaches the street, he throws his body back, tilts his
outspread wings nearly square to the course, and on the cushion
of air thus encountered he stops his speed and drops lightly to
the ground.  So do all birds.  We tried it with misgivings, but
found it perfectly effective.  The soft sand was a great
advantage, and even when the experts were racing there was not a
single sprained ankle.'

With the multiple winged glider some two to three hundred glides
were made without any accident either to the man or to the
machine, and the action was found so effective, the principle so
sound, that full plans were published for the benefit of any
experimenters who might wish to improve on this apparatus.  The
American Aeronautical Annual for 1897 contains these plans;
Chanute confessed that some movement on the part of the operator
was still required to control the machine, but it was only a
seventh or a sixth part of the movement required for control of
the Lilienthal type.

Chanute waxed enthusiastic over the possibilities of gliding,
concerning which he remarks that 'There is no more delightful
sensation than that of gliding through the air.  All the
faculties are on the alert, and the motion is astonishingly
smooth and elastic.  The machine responds instantly to the
slightest movement of the operator; the air rushes by one's
ears; the trees and bushes flit away underneath, and the landing
comes all too quickly.  Skating, sliding, and bicycling are not
to be compared for a moment to aerial conveyance, in which,
perhaps, zest is added by the spice of danger.  For it must be
distinctly understood that there is constant danger in such
preliminary experiments.  When this hazard has been eliminated
by further evolution, gliding will become a most popular sport.'

Later experiments proved that the biplane type of glider gave
better results than the rather cumbrous model consisting of five
tiers of planes.  Longer and more numerous glides, to the number
of seven to eight hundred, were obtained, the rate of descent
being about one in six.  The longest distance traversed was
about 120 yards, but Chanute had dreams of starting from a hill
about 200 feet high, which would have given him gliding flights
of 1,200 feet.  He remarked that 'In consequence of the speed
gained by running, the initial stage of the flight is nearly
horizontal, and it is thrilling to see the operator pass from
thirty to forty feet overhead, steering his machine, undulating
his course, and struggling with the wind-gusts which whistle
through the guy wires.  The automatic mechanism restores the
angle of advance when compromised by variations of the breeze;
but when these come from one side and tilt the apparatus, the
weight has to be shifted to right the machine... these gusts
sometimes raise the machine from ten to twenty feet vertically,
and sometimes they strike the apparatus from above, causing it
to descend suddenly.  When sailing near the ground, these
vicissitudes can be counteracted by movements of the body from
three to four inches; but this has to be done instantly, for
neither wings nor gravity will wait on meditation.  At a height
of three hundred or four hundred feet the regulating mechanism
would probably take care of these wind-gusts, as it does, in
fact, for their minor variations.  The speed of the machine is
generally about seventeen miles an hour over the ground, and
from twenty-two to thirty miles an hour relative to the air.
Constant effort was directed to keep down the velocity, which
was at times fifty-two miles an hour.  This is the purpose of
the starting and gliding against the wind, which thus furnishes
an initial velocity without there being undue speed at the
landing.  The highest wind we dared to experiment in blew at
thirty-one miles an hour; when the wind was stronger, we waited
and watched the birds.'

Chanute details an amusing little incident which occurred in the
course of experiment with the biplane glider.  He says that 'We
had taken one of the machines to the top of the hill, and loaded
its lower wings with sand to hold it while we e went to lunch. 
A gull came strolling inland, and flapped full-winged to
inspect.  He swept several circles above the machine, stretched
his neck, gave a squawk and went off.  Presently he returned
with eleven other gulls, and they seemed to hold a conclave
about one hundred feet above the big new white bird which they
had discovered on the sand.  They circled round after round, and
once in a while there was a series of loud peeps, like those of
a rusty gate, as if in conference, with sudden flutterings, as
if a terrifying suggestion had been made.  The bolder birds
occasionally swooped downwards to inspect the monster more
closely; they twisted their heads around to bring first one eye
and then the other to bear, and then they rose again.  After
some seven or eight minutes of this performance, they evidently
concluded either that the stranger was too formidable to tackle,
if alive, or that he was not good to eat, if dead, and they flew
off to resume fishing, for the weak point about a bird is his
stomach.'

The gliders were found so stable, more especially the biplane
form, that in the end Chanute permitted amateurs to make trials
under guidance, and throughout the whole series of experiments
not a single accident occurred. Chanute came to the conclusion
that any young, quick, and handy man could master a gliding
machine almost as soon as he could get the hang of a bicycle,
although the penalty for any mistake would be much more severe.

At the conclusion of his experiments he decided that neither the
multiple plane nor the biplane type of glider was sufficiently
perfected for the application of motive power.  In spite of the
amount of automatic stability that he had obtained he considered
that there was yet more to be done, and he therefore advised
that every possible method of securing stability and safety
should be tested, first with models, and then with full-sized
machines; designers, he said, should make a point of practice in
order to make sure of the action, to proportion and adjust the
parts of their machine, and to eliminate hidden defects.
Experimental flight, he suggested, should be tried over water,
in order to break any accidental fall; when a series of
experiments had proved the stability of a glider, it would then
be time to apply motive power.  He admitted that such a process
would be both costly and slow, but, he said, that 'it greatly
diminished the chance of those accidents which bring a whole
line of investigation into contempt.' He saw the flying machine
as what it has, in fact, been; a child of evolution, carried on
step by step by one investigator after another, through the
stages of doubt and perplexity which lie behind the realm of
possibility, beyond which is the present day stage of actual
performance and promise of ultimate success and triumph over the
earlier, more cumbrous, and slower forms of the transport that
we know.

Chanute's monograph, from which the foregoing notes have been
comprised, was written soon after the conclusion of his series
of experiments.  He does not appear to have gone in for further
practical work, but to have studied the subject from a
theoretical view-point and with great attention to the work done
by others.  In a paper contributed in 1900 to the American
Independent, he remarks that 'Flying machines promise better
results as to speed, but yet will be of limited commercial
application.  They may carry mails and reach other inaccessible
places, but they cannot compete with railroads as carriers of
passengers or freight.  They will not fill the heavens with
commerce, abolish custom houses, or revolutionise the world, for
they will be expensive for the loads which they can carry, and
subject to too many weather contingencies.  Success is, however,
probable.  Each experimenter has added something to previous
knowledge which his successors can avail of.  It now seems
likely that two forms of flying machines, a sporting type and an
exploration type, will be gradually evolved within one or two
generations, but the evolution will be costly and slow, and must
be carried on by well-equipped and thoroughly informed
scientific men; for the casual inventor, who relies upon one or
two happy inspirations, will have no chance of success
whatever.'

Follows Professor John J. Montgomery, who, in the true American
spirit, describes his own experiments so well that nobody can
possibly do it better.  His account of his work was given first
of all in the American Journal, Aeronautics, in January, 1909,
and thence transcribed in the English paper of the same name in
May, 1910, and that account is here copied word for word.  It
may, however, be noted first that as far back as 1860, when
Montgomery was only a boy, he was attracted to the study of
aeronautical problems, and in 1883 he built his first machine,
which was of the flapping-wing ornithopter type, and which
showed its designer, with only one experiment, that he must
design some other form of machine if he wished to attain to a
successful flight.  Chanute details how, in 1884 and 1885
Montgomery built three gliders, demonstrating the value of
curved surfaces.  With the first of these gliders Montgomery
copied the wing of a seagull; with the second he proved that a
flat surface was virtually useless, and with the third he
pivoted his wings as in the Antoinette type of power-propelled
aeroplane, proving to his own satisfaction that success lay in
this direction.  His own account of the gliding flights carried
out under his direction is here set forth, being the best
description of his work that can be obtained:--

'When I commenced practical demonstration in my work with
aeroplanes I had before me three points; first, equilibrium;
second, complete control; and third, long continued or soaring
flight.  In starting I constructed and tested three sets of
models, each in advance of the other in regard to the
continuance of their soaring powers, but all equally perfect as
to equilibrium and control.  These models were tested by
dropping them from a cable stretched between two mountain tops,
with various loads, adjustments and positions.  And it made no
difference whether the models were dropped upside down or any
other conceivable position, they always found their equilibrium
immediately and glided safely to earth.

'Then I constructed a large machine patterned after the first
model, and with the assistance of three cowboy friends
personally made a number of flights in the steep mountains near
San Juan (a hundred miles distant).  In making these flights I
simply took the aeroplane and made a running jump.  These tests
were discontinued after I put my foot into a squirrel hole in
landing and hurt my leg.

'The following year I commenced the work on a larger scale, by
engaging aeronauts to ride my aeroplane dropped from balloons. 
During this work I used five hot-air balloons and one gas
balloon, five or six aeroplanes, three riders--Maloney, Wilkie,
and Defolco--and had sixteen applicants on my list, and had a
training station to prepare any when I needed them.

'Exhibitions were given in Santa Cruz, San Jose, Santa Clara,
Oaklands, and Sacramento.  The flights that were made, instead
of being haphazard affairs, were in the order of safety and
development.  In the first flight of an aeronaut the aeroplane
was so arranged that the rider had little liberty of action,
consequently he could make only a limited flight.  In some of
the first flights, the aeroplane did little more than settle in
the air.  But as the rider gained experience in each successive
flight I changed the adjustments, giving him more liberty of
action, so he could obtain longer flights and more varied
movements in the flights.  But in none of the flights did I have
the adjustments so that the riders had full liberty, as I did
not consider that they had the requisite knowledge and
experience necessary for their safety; and hence, none of my
aeroplanes were launched so arranged that the rider could make
adjustments necessary for a full flight.

'This line of action caused a good deal of trouble with
aeronauts or riders, who had unbounded confidence and wanted to
make long flights after the first few trials; but I found it
necessary, as they seemed slow in comprehending the important
elements and were willing to take risks.  To give them the full
knowledge in these matters I was formulating plans for a large
starting station on the Mount Hamilton Range from which I could
launch an aeroplane capable of carrying two, one of my aeronauts
and myself, so I could teach him by demonstration.  But the
disasters consequent on the great earthquake completely stopped
all my work on these lines.  The flights that were given were
only the first of the series with aeroplanes patterned after the
first model.  There were no aeroplanes constructed according to
the two other models, as I had not given the full demonstration
of the workings of the first, though some remarkable and
startling work was done.  On one occasion Maloney, in trying to
make a very short turn in rapid flight, pressed very hard on the
stirrup which gives a screw-shape to the wings, and made a side
somersault.  The course of the machine was very much like one
turn of a corkscrew.  After this movement the machine continued
on its regular course.  And afterwards Wilkie, not to be outdone
by Maloney, told his friends he would do the same, and in a
subsequent flight made two side somersaults, one in one
direction and the other in an opposite, then made a deep dive
and a long glide, and, when about three hundred feet in the air,
brought the aeroplane to a sudden stop and settled to the earth. 
After these antics, I decreased the extent of the possible
change in the form of wing-surface, so as to allow only straight
sailing or only long curves in turning.

'During my work I had a few carping critics that I silenced by
this standing offer:  If they would deposit a thousand dollars I
would cover it on this proposition.  I would fasten a 150 pound
sack of sand in the rider's seat, make the necessary
adjustments, and send up an aeroplane upside down with a
balloon, the aeroplane to be liberated by a time fuse.  If the
aeroplane did not immediately right itself, make a flight, and
come safely to the ground, the money was theirs.

'Now a word in regard to the fatal accident.  The circumstances
are these:  The ascension was given to entertain a military
company in which were many of Maloney's friends, and he had told
them he would give the most sensational flight they ever heard
of.  As the balloon was rising with the aeroplane, a guy rope
dropping switched around the right wing and broke the tower that
braced the two rear wings and which also gave control over the
tail.  We shouted Maloney that the machine was broken, but he
probably did not hear us, as he was at the same time saying,
"Hurrah for Montgomery's airship," and as the break was behind
him, he may not have detected it.  Now did he know of the
breakage or not, and if he knew of it did he take a risk so as
not to disappoint his friends?  At all events, when the machine
started on its flight the rear wings commenced to flap (thus
indicating they were loose), the machine turned on its back, and
settled a little faster than a parachute.  When we reached
Maloney he was unconscious and lived only thirty minutes.  The
only mark of any kind on him was a scratch from a wire on the
side of his neck.  The six attending physicians were puzzled at
the cause of his death.  This is remarkable for a vertical
descent of over 2,000 feet.'

The flights were brought to an end by the San Francisco
earthquake in April, 1906, which, Montgomery states, 'Wrought
such a disaster that I had to turn my attention to other
subjects and let the aeroplane rest for a time.'  Montgomery
resumed experiments in 1911 in California, and in October of
that year an accident brought his work to an end.  The report in
the American Aeronautics says that 'a little whirlwind caught
the machine and dashed it head on to the ground; Professor
Montgomery landed on his head and right hip.  He did not believe
himself seriously hurt, and talked with his year-old bride in
the tent.  He complained of pains in his back, and continued to
grow worse until he died.'



IX.  NOT PROVEN

The early history of flying, like that of most sciences, is
replete with tragedies; in addition to these it contains one
mystery concerning Clement Ader, who was well known among
European pioneers in the development of the telephone, and first
turned his attention to the problems of mechanical flight in
1872.  At the outset he favoured the ornithopter principle,
constructing a machine in the form of a bird with a wing-spread
of twenty-six feet; this, according to Ader's conception, was to
fly through the efforts of the operator.  The result of such an
attempt was past question and naturally the machine never left
the ground.

A pause of nineteen years ensued, and then in 1886 Ader turned
his mind to the development of the aeroplane, constructing a
machine of bat-like form with a wingspread of about forty-six
feet, a weight of eleven hundred pounds, and a steam-power plant
of between twenty and thirty horse-power driving a four-bladed
tractor screw.  On October 9th, 1890, the first trials of this
machine were made, and it was alleged to have flown a distance
of one hundred and sixty-four feet.  Whatever truth there may be
in the allegation, the machine was wrecked through deficient
equilibrium at the end of the trial.  Ader repeated the
construction, and on October 14th, 1897, tried out his third
machine at the military establishment at Satory in the presence
of the French military authorities, on a circular track
specially prepared for the experiment.  Ader and his friends
alleged that a flight of nearly a thousand feet was made; again
the machine was wrecked at the end of the trial, and there
Ader's practical work may be said to have ended, since no more
funds were forthcoming for the subsidy of experiments.

There is the bald narrative, but it is worthy of some
amplification.  If Ader actually did what he claimed, then the
position which the Wright Brothers hold as first to navigate the
air in a power-driven plane is nullified.  Although at this time
of writing it is not a quarter of a century since Ader's
experiment in the presence of witnesses competent to judge on
his accomplishment, there is no proof either way, and whether he
was or was not the first man to fly remains a mystery in the
story of the conquest of the air.

The full story of Ader's work reveals a persistence and
determination to solve the problem that faced him which was
equal to that of Lilienthal.  He began by penetrating into the
interior of Algeria after having disguised himself as an Arab,
and there he spent some months in studying flight as practiced
by the vultures of the district.  Returning to France in 1886 he
began to construct the 'Eole,' modelling it, not on the vulture,
but in the shape of a bat.  Like the Lilienthal and Pilcher
gliders this machine was fitted with wings which could be
folded; the first flight made, as already noted, on October 9th,
1890, took place in the grounds of the chateau d'Amainvilliers,
near Bretz; two fellow-enthusiasts named Espinosa and Vallier
stated that a flight was actually made; no statement in the
history of aeronautics has been subject of so much question, and
the claim remains unproved.

It was in September of 1891 that Ader, by permission of the
Minister of War, moved the 'Eole' to the military establishment
at Satory for the purpose of further trial.  By this time,
whether he had flown or not, his nineteen years of work in
connection with the problems attendant on mechanical flight had
attracted so much attention that henceforth his work was subject
to the approval of the military authorities, for already it was
recognised that an efficient flying machine would confer an
inestimable advantage on the power that possessed it in the
event of war.  At Satory the 'Eole' was alleged to have made a
flight of 109 yards, or, according to another account, 164 feet,
as stated above, in the trial in which the machine wrecked
itself through colliding with some carts which had been placed
near the track--the root cause of this accident, however, was
given as deficient equilibrium.

Whatever the sceptics may say, there is reason for belief in the
accomplishment of actual flight by Ader with his first machine
in the fact that, after the inevitable official delay of some
months, the French War Ministry granted funds for further
experiment.  Ader named his second machine, which he began to
build in May, 1892, the 'Avion,' and--an honour which he well
deserve--that name remains in French aeronautics as descriptive
of the power-driven aeroplane up to this day.

This second machine, however, was not a success, and it was not
until 1897 that the second 'Avion,' which was the third
power-driven aeroplane of Ader's construction, was ready for
trial.  This was fitted with two steam motors of twenty
horse-power each, driving two four-bladed propellers; the wings
warped automatically:  that is to say, if it were necessary to
raise the trailing edge of one wing on the turn, the trailing
edge of the opposite wing was also lowered by the same movement;
an under-carriage was also fitted, the machine running on three
small wheels, and levers controlled by the feet of the aviator
actuated the movement of the tail planes.

On October the 12th, 1897, the first trials of this 'Avion' were
made in the presence of General Mensier, who admitted that the
machine made several hops above the ground, but did not consider
the performance as one of actual flight.  The result was so
encouraging, in spite of the partial failure, that, two days
later, General Mensier, accompanied by General Grillon, a
certain Lieutenant Binet, and two civilians named respectively
Sarrau and Leaute, attended for the purpose of giving the
machine an official trial, over which the great controversy
regarding Ader's success or otherwise may be said to have
arisen.

We will take first Ader's own statement as set out in a very
competent account of his work published in Paris in 1910.  Here
are Ader's own words:  'After some turns of the propellers, and
after travelling a few metres, we started off at a lively pace;
the pressure-gauge registered about seven atmospheres; almost
immediately the vibrations of the rear wheel ceased; a little
later we only experienced those of the front wheels at
intervals.  'Unhappily, the wind became suddenly strong, and we
had some difficulty in keeping the "Avion" on the white line. 
We increased the pressure to between eight and nine atmospheres,
and  immediately the speed increased considerably, and the
vibrations of the wheels were no longer sensible; we were at
that moment at the point marked G in the sketch; the "Avion"
then found itself freely supported by its wings; under the
impulse of the wind it continually tended to go outside the
(prepared) area to the right, in spite of the action of the
rudder.  On reaching the point V it found itself in a very
critical position; the wind blew strongly and across the
direction of the white line which it ought to follow; the
machine then, although still going forward, drifted quickly out
of the area; we immediately put over the rudder to the left as
far as it would go; at the same time increasing the pressure
still more, in order to try to regain the course.  The "Avion"
obeyed, recovered a little, and remained for some seconds headed
towards its intended course, but it could not struggle against
the wind; instead of going back, on the contrary it drifted
farther and farther away.  And ill-luck had it that the drift
took the direction towards part of the School of Musketry, which
was guarded by posts and barriers.  Frightened at the prospect
of breaking ourselves against these obstacles, surprised at
seeing the earth getting farther away from under the "Avion,"
and very much impressed by seeing it rushing sideways at a
sickening speed, instinctively we stopped everything.  What
passed through our thoughts at this moment which threatened a
tragic turn would be difficult to set down.  All at once came a
great shock, splintering, a heavy concussion:  we had landed.'

Thus speaks the inventor; the cold official mind gives out a
different account, crediting the 'Avion' with merely a few hops,
and to-day, among those who consider the problem at all, there
is a little group which persists in asserting that to Ader
belongs the credit of the first power-driven flight, while a
larger group is equally persistent in stating that, save for a
few ineffectual hops, all three wheels of the machine never left
the ground.  It is past question that the 'Avion' was capable of
power-driven flight; whether it achieved it or no remains an
unsettled problem.

Ader's work is negative proof of the value of such experiments
as Lilienthal, Pilcher, Chanute, and Montgomery conducted; these
four set to work to master the eccentricities of the air before
attempting to use it as a supporting medium for continuous
flight under power; Ader attacked the problem from the other
end; like many other experimenters he regarded the air as a
stable fluid capable of giving such support to his machine as
still water might give to a fish, and he reckoned that he had
only to produce the machine in order to achieve flight.  The
wrecked 'Avion' and the refusal of the French War Ministry to
grant any more funds for further experiment are sufficient
evidence of the need for working along the lines taken by the
pioneers of gliding rather than on those which Ader himself
adopted.

Let it not be thought that in this comment there is any desire
to derogate from the position which Ader should occupy in any
study of the pioneers of aeronautical enterprise.  If he failed,
he failed magnificently, and if he succeeded, then the student
of aeronautics does him an injustice and confers on the Brothers
Wright an honour which, in spite of the value of their work,
they do not deserve.  There was one earlier than Ader, Alphonse
Penaud, who, in the face of a lesser disappointment than that
which Ader must have felt in gazing on the wreckage of his
machine, committed suicide; Ader himself, rendered unable to do
more, remained content with his achievement, and with the
knowledge that he had played a good part in the long search
which must eventually end in triumph.  Whatever the world might
say, he himself was certain that he had achieved flight.  This,
for him, was perforce enough.

Before turning to consideration of the work accomplished by the
Brothers Wright, and their proved conquest of the air, it is
necessary first to sketch as briefly as may be the experimental
work of Sir (then Mr) Hiram Maxim, who, in his book, Artificial
and Natural Flight, has given a fairly complete account of his
various experiments.  He began by experimenting with models,
with screw-propelled planes so attached to a horizontal movable
arm that when the screw was set in motion the plane described a
circle round a central point, and, eventually, he built a giant
aeroplane having a total supporting area of 1,500 square feet,
and a wing-span of fifty feet.  It has been thought advisable to
give a fairly full description of the power plant used to the
propulsion of this machine in the section devoted to engine
development.  The aeroplane, as Maxim describes it, had five
long and narrow planes projecting from each side, and a main or
central plane of pterygoid aspect.  A fore and aft rudder was
provided, and had all the auxiliary planes been put in position
for experimental work a total lifting surface of 6,000 square
feet could have been obtained.  Maxim, however, did not use more
than 4,000 square feet of lifting surface even in his later
experiments; with this he judged the machine capable of lifting
slightly under 8,000 lbs. weight, made up of 600 lbs. water in
the boiler and tank, a crew of three men, a supply of naphtha
fuel, and the weight of the machine itself.

Maxim's intention was, before attempting free flight, to get as
much data as possible regarding the conditions under which
flight must be obtained, by what is known in these days as
'taxi-ing'--that is, running the propellers at sufficient speed
to drive the machine along the ground without actually mounting
into the air.  He knew that he had an immense lifting surface
and a tremendous amount of power in his engine even when the
total weight of the experimental plant was taken into
consideration, and thus he set about to devise some means of
keeping the machine on the nine foot gauge rail track which had
been constructed for the trials.  At the outset he had a set of
very heavy cast-iron wheels made on which to mount the machine,
the total weight of wheels, axles, and connections being about
one and a half tons.  These were so constructed that the light
flanged wheels which supported the machine on the steel rails
could be lifted six inches above the track, still leaving the
heavy wheels on the rails for guidance of the machine.  'This
arrangement,' Maxim states, 'was tried on several occasions, the
machine being run fast enough to lift the forward end off the
track.  However, I found considerable difficulty in starting and
stopping quickly on account of the great weight, and the amount
of energy necessary to set such heavy wheels spinning at a high
velocity.  The last experiment with these wheels was made when a
head wind was blowing at the rate of about ten miles an hour. 
It was rather unsteady, and when the machine was running at its
greatest velocity, a sudden gust lifted not only the front end,
but also the heavy front wheels completely off the track, and
the machine falling on soft ground was soon blown over by the
wind.'

Consequently, a safety track was provided, consisting of squared
pine logs, three inches by nine inches, placed about two feet
above the steel way and having a thirty-foot gauge.  Four extra
wheels were fitted to the machine on outriggers and so adjusted
that, if the machine should lift one inch clear of the steel
rails, the wheels at the ends of the outriggers would engage the
under side of the pine trackway.

The first fully loaded run was made in a dead calm with 150 lbs. 
steam pressure to the square inch, and there was no sign of the
wheels leaving the steel track.  On a second run, with 230 lbs. 
steam pressure the machine seemed to alternate between adherence
to the lower and upper tracks, as many as three of the outrigger
wheels engaging at the same time, and the weight on the steel
rails being reduced practically to nothing.  In preparation for
a third run, in which it was intended to use full power, a
dynamometer was attached to the machine and the engines were
started at 200 lbs. pressure, which was gradually increased to
310 lbs per square inch.  The incline of the track, added to the
reading of the dynamometer, showed a total screw thrust of 2,164
lbs.  After the dynamometer test had been completed, and
everything had been made ready for trial in motion, careful
observers were stationed on each side of the track, and the
order was given to release the machine.  What follows is best
told in Maxim's own words:--

'The enormous screw-thrust started the engine so quickly that it
nearly threw the engineers off their feet, and the machine
bounded over the track at a great rate. Upon noticing a slight
diminution in the steam pressure, I turned on more gas, when
almost instantly the steam commenced to blow a steady blast from
the small safety valve, showing that the pressure was at least
320 lbs. in the pipes supplying the engines with steam.  Before
starting on this run, the wheels that were to engage the upper
track were painted, and it was the duty of one of my assistants
to observe these wheels during the run, while another assistant
watched the pressure gauges and dynagraphs. The first part of
the track was up a slight incline, but the machine was lifted
clear of the lower rails and all of the top wheels were fully
engaged on the upper track when about 600 feet had been covered. 
The speed rapidly increased, and when 900 feet had been covered,
one of the rear axle trees, which were of two-inch steel tubing,
doubled up and set the rear end of the machine completely free. 
The pencils ran completely across the cylinders of the
dynagraphs and caught on the underneath end.  The rear end of
the machine being set free, raised considerably above the track
and swayed.  At about 1,000 feet, the left forward wheel also
got clear of the upper track, and shortly afterwards the right
forward wheel tore up about 100 feet of the upper track. Steam
was at once shut off and the machine sank directly to the earth,
embedding the wheels in the soft turf without leaving any other
marks, showing most conclusively that the machine was completely
suspended in the air before it settled to the earth.  In this
accident, one of the pine timbers forming the upper track went
completely through the lower framework of the machine and broke
a number of the tubes, but no damage was done to the machinery
except a slight injury to one of the screws.'

It is a pity that the multifarious directions in which Maxim
turned his energies did not include further development of the
aeroplane, for it seems fairly certain that he was as near
solution of the problem as Ader himself, and, but for the
holding-down outer track, which was really the cause of his
accident, his machine would certainly have achieved free flight,
though whether it would have risen, flown and alighted, without
accident, is matter for conjecture.

The difference between experiments with models and with
full-sized machines is emphasised by Maxim's statement to the
effect that with a small apparatus for ascertaining the power
required for artificial flight, an angle of incidence of one in
fourteen was most advantageous, while with a large machine he
found it best to increase his angle to one in eight in order to
get the maximum lifting effect on a short run at a moderate
speed.  He computed the total lifting effect in the experiments
which led to the accident as not less than 10,000 lbs., in which
is proof that only his rail system prevented free flight.



X. SAMUEL PIERPOINT LANGLEY

Langley was an old man when he began the study of aeronautics,
or, as he himself might have expressed it, the study of
aerodromics, since he persisted in calling the series of
machines he built 'Aerodromes,' a word now used only to denote
areas devoted to use as landing spaces for flying machines; the
Wright Brothers, on the other hand, had the great gift of youth
to aid them in their work.  Even so it was a great race between
Langley, aided by Charles Manly, and Wilbur and Orville Wright,
and only the persistent ill-luck which dogged Langley from the
start to the finish of his experiments gave victory to his
rivals.  It has been proved conclusively in these later years of
accomplished flight that the machine which Langley launched on
the Potomac River in October of 1903 was fully capable of
sustained flight, and only the accidents incurred in launching
prevented its pilot from being the first man to navigate the air
successfully in a power-driven machine.

The best account of Langley's work is that diffused throughout a
weighty tome issued by the Smithsonian Institution, entitled the
Langley Memoir on Mechanical Flight, of which about one-third
was written by Langley himself, the remainder being compiled by
Charles M. Manly, the engineer responsible for the construction
of the first radial aero-engine, and chief assistant to Langley
in his experiments.  To give a twentieth of the contents of this
volume in the present short account of the development of
mechanical flight would far exceed the amount of space that can
be devoted even to so eminent a man in aeronautics as S. P.
Langley, who, apart from his achievement in the construction of
a power-driven aeroplane really capable of flight, was a
scientist of no mean order, and who brought to the study of
aeronautics the skill of the trained investigator allied to the
inventive resource of the genius.

That genius exemplified the antique saw regarding the infinite
capacity for taking pains, for the Langley Memoir shows that as
early as 1891 Langley had completed a set of experiments,
lasting through years, which proved it possible to construct
machines giving such a velocity to inclined surfaces that bodies
indefinitely heavier than air could be sustained upon it and
propelled through it at high speed.  For full account (very
full) of these experiments, and of a later series leading up to
the construction of a series of 'model aerodromes' capable of
flight under power, it is necessary to turn to the bulky memoir
of Smithsonian origin.

The account of these experiments as given by Langley himself
reveals the humility of the true investigator. Concerning them,
Langley remarks that, 'Everything here has been done with a view
to putting a trial aerodrome successfully in flight within a few
years, and thus giving an early demonstration of the only kind
which is conclusive in the eyes of the scientific man, as well
as of the general public--a demonstration that mechanical flight
is possible--by actually flying.  All that has been done has
been with an eye principally to this immediate result, and all
the experiments given in this book are to be considered only as
approximations to exact truth.  All were made with a view, not
to some remote future, but to an arrival within the compass of a
few years at some result in actual flight that could not be
gainsaid or mistaken.'

With a series of over thirty rubber-driven models Langley
demonstrated the practicability of opposing curved surfaces to
the resistance of the air in such a way as to achieve flight, in
the early nineties of last century; he then set about finding
the motive power which should permit of the construction of
larger machines, up to man-carrying size.  The internal
combustion engine was then an unknown quantity, and he had to
turn to steam, finally, as the propulsive energy for his power
plant.  The chief problem which faced him was that of the
relative weight and power of his engine; he harked back to the
Stringfellow engine of 1868, which in 1889 came into the
possession of the Smithsonian Institution as a historical
curiosity.  Rightly or wrongly Langley concluded on examination
that this engine never had developed and never could develop
more than a tenth of the power attributed to it; consequently he
abandoned the idea of copying the Stringfellow design and set
about making his own engine.

How he overcame the various difficulties that faced him and
constructed a steam-engine capable of the task allotted to it
forms a story in itself, too long for recital here.  His first
power-driven aerodrome of model size was begun in November of
1891, the scale of construction being decided with the idea that
it should be large enough to carry an automatic steering
apparatus which would render the machine capable of maintaining
a long and steady flight.  The actual weight of the first model
far exceeded the theoretical estimate, and Langley found that a
constant increase of weight under the exigencies of construction
was a feature which could never be altogether eliminated.  The
machine was made principally of steel, the sustaining surfaces
being composed of silk stretched from a steel tube with wooden
attachments.  The first engines were the oscillating type, but
were found deficient in power.  This led to the construction of
single-acting inverted oscillating engines with high and low
pressure cylinders, and with admission and exhaust ports to
avoid the complication and weight of eccentric and valves. 
Boiler and furnace had to be specially designed; an analysis of
sustaining surfaces and the settlement of equilibrium while in
flight had to be overcome, and then it was possible to set about
the construction of the series of model aerodromes and make test
of their 'lift.'

By the time Langley had advanced sufficiently far to consider it
possible to conduct experiments in the open air, even with these
models, he had got to his fifth aerodrome, and to the year 1894. 
Certain tests resulted in failure, which in turn resulted in
further modifications of design, mainly of the engines.  By
February of 1895 Langley reported that under favourable
conditions a lift of nearly sixty per cent of the flying weight
was secured, but although this was much more than was required
for flight, it was decided to postpone trials until two machines
were ready for the test.  May, 1896, came before actual trials
were made, when one machine proved successful and another, a
later design, failed.  The difficulty with these models was that
of securing a correct angle for launching; Langley records how,
on launching one machine, it rose so rapidly that it attained an
angle of sixty degrees and then did a tail slide into the water
with its engines working at full speed, after advancing nearly
forty feet and remaining in the air for about three seconds. 
Here, Langley found that he had to obtain greater rigidity in
his wings, owing to the distortion of the form of wing under
pressure, and how he overcame this difficulty constitutes yet
another story too long for the telling here.

Field trials were first attempted in 1893, and Langley blamed
his launching apparatus for their total failure. There was a
brief, but at the same time practical, success in model flight
in 1894, extending to between six and seven seconds, but this
only proved the need for strengthening of the wing.  In 1895
there was practically no advance toward the solution of the
problem, but the flights of May 6th and November 28th, 1896,
were notably successful.  A diagram given in Langley's memoir
shows the track covered by the aerodrome on these two flights;
in the first of them the machine made three complete circles,
covering a distance of 3,200 feet; in the second, that of
November 28th, the distance covered was 4,200 feet, or about
three-quarters of a mile, at a speed of about thirty miles an
hour.

These achievements meant a good deal; they proved mechanically
propelled flight possible.  The difference between them and such
experiments as were conducted by Clement Ader, Maxim, and
others, lay principally in the fact that these latter either did
or did not succeed in rising into the air once, and then, either
willingly or by compulsion, gave up the quest, while Langley
repeated his experiments and thus attained to actual proof of
the possibilities of flight.  Like these others, however, he
decided in 1896 that he would not undertake the construction of
a large man-carrying machine.  In addition to a multitude of
actual duties, which left him practically no time available for
original research, he had as an adverse factor fully ten years
of disheartening difficulties in connection with his model
machines.  It was President McKinley who, by requesting Langley
to undertake the construction and test of a machine which might
finally lead to the development of a flying machine capable of
being used in warfare, egged him on to his final experiment. 
Langley's acceptance of the offer to construct such a machine is
contained in a letter addressed from the Smithsonian Institution
on December 12th, 1898, to the Board of Ordnance and
Fortification of the United States War Department; this letter
is of such interest as to render it worthy of reproduction:--

'Gentlemen,--In response to your invitation I repeat what I had
the honour to say to the Board--that I am willing, with the
consent of the Regents of this Institution, to undertake for the
Government the further investigation of the subject of the
construction of a flying machine on a scale capable of carrying
a man, the investigation to include the construction,
development and test of such a machine under conditions left as
far as practicable in my discretion, it being understood that my
services are given to the Government in such time as may not be
occupied by the business of the Institution, and without charge.

'I have reason to believe that the cost of the construction will
come within the sum of $50,000.00, and that not more than
one-half of that will be called for in the coming year.

'I entirely agree with what I understand to be the wish of the
Board that privacy be observed with regard to the work, and only
when it reaches a successful completion shall I wish to make
public the fact of its success.

'I attach to this a memorandum of my understanding of some
points of detail in order to be sure that it is also the
understanding of the Board, and I am, gentlemen, with much
respect, your obedient servant, S. P. Langley.'

One of the chief problems in connection with the construction of
a full-sized apparatus was that of the construction of an
engine, for it was realised from the first that a steam power
plant for a full-sized machine could only be constructed in such
a way as to make it a constant menace to the machine which it
was to propel. By this time (1898) the internal combustion
engine had so far advanced as to convince Langley that it formed
the best power plant available.  A contract was made for the
delivery of a twelve horse-power engine to weigh not more than a
hundred pounds, but this contract was never completed, and it
fell to Charles M. Manly to design the five-cylinder radial
engine, of which a brief account is included in the section of
this work devoted to aero engines, as the power plant for the
Langley machine.

The history of the years 1899 to 1903 in the Langley series of
experiments contains a multitude of detail far beyond the scope
of this present study, and of interest mainly to the designer. 
There were frames, engines, and propellers, to be considered,
worked out, and constructed.  We are concerned here mainly with
the completed machine and its trials.  Of these latter it must
be remarked that the only two actual field trials which took
place resulted in accidents due to the failure of the launching
apparatus, and not due to any inherent defect in the machine. 
It was intended that these two trials should be the first of a
series, but the unfortunate accidents, and the fact that no
further funds were forthcoming for continuance of experiments,
prevented Langley's success, which, had he been free to go
through as he intended with his work, would have been certain.

The best brief description of the Langley aerodrome in its final
form, and of the two attempted trials, is contained in the
official report of Major M. M. Macomb of the United States
Artillery Corps, which report is here given in full:--

                         REPORT

Experiments with working models which were concluded August 8
last having proved the principles and calculations on which the
design of the Langley aerodrome was based to be correct, the
next step was to apply these principles to the construction of a
machine of sufficient size and power to permit the carrying of a
man, who could control the motive power and guide its flight,
thus pointing the way to attaining the final goal of producing a
machine capable of such extensive and precise aerial flight,
under normal atmospheric conditions, as to prove of military or
commercial utility.

Mr C. M. Manly, working under Professor Langley, had, by the
summer of 1903, succeeded in completing an engine-driven machine
which under favourable atmospheric conditions was expected to
carry a man for any time up to half an hour, and to be capable
of having its flight directed and controlled by him.

The supporting surface of the wings was ample, and experiment
showed the engine capable of supplying more than the necessary
motive power.

Owing to the necessity of lightness, the weight of the various
elements had to be kept at a minimum, and the factor of safety
in construction was therefore exceedingly small, so that the
machine as a whole was delicate and frail and incapable of
sustaining any unusual strain.  This defect was to be corrected
in later models by utilising data gathered in future experiments
under varied conditions.

One of the most remarkable results attained was the production
of a gasoline engine furnishing over fifty continuous
horse-power for a weight of 120 lbs.

The aerodrome, as completed and prepared for test, is briefly
described by Professor Langley as 'built of steel, weighing
complete about 730 lbs., supported by 1,040 feet of sustaining
surface, having two propellers driven by a gas engine developing
continuously over fifty brake horse-power.'

The appearance of the machine prepared for flight was
exceedingly light and graceful, giving an impression to all
observers of being capable of successful flight.

On October 7 last everything was in readiness, and I witnessed
the attempted trial on that day at Widewater, Va.  On the
Potomac.  The engine worked well and the machine was launched at
about 12.15 p.m.  The trial was unsuccessful because the front
guy-post caught in its support on the launching car and was not
released in time to give free flight, as was intended, but, on
the contrary, caused the front of the machine to be dragged
downward, bending the guy-post and making the machine plunge
into the water about fifty yards in front of the house-boat. 
The machine was subsequently recovered and brought back to the
house-boat.  The engine was uninjured and the frame only slightly
damaged, but the four wings and rudder were practically destroyed
by the first plunge and subsequent towing back to the house-boat.

This accident necessitated the removal of the house-boat to
Washington for the more convenient repair of damages.

On December 8 last, between 4 and 5 p.m., another attempt at a
trial was made, this time at the junction of the Anacostia with
the Potomac, just below Washington Barracks.

On this occasion General Randolph and myself represented the
Board of Ordnance and Fortification.  The launching car was
released at 4.45 p.m. being pointed up the Anacostia towards the
Navy Yard.  My position was on the tug Bartholdi, about 150 feet
from and at right angles to the direction of proposed flight. 
The car was set in motion and the propellers revolved rapidly,
the engine working perfectly, but there was something wrong with
the launching.  The rear guy-post seemed to drag, bringing the
rudder down on the launching ways, and a crashing, rending
sound, followed by the collapse of the rear wings, showed that
the machine had been wrecked in the launching, just how, it was
impossible for me to see.  The fact remains that the rear wings
and rudder were wrecked before the machine was free of the ways. 
Their collapse deprived the machine of its support in the rear,
and it consequently reared up in front under the action of the
motor, assumed a vertical position, and then toppled over to the
rear, falling into the water a few feet in front of the boat.

Mr Manly was pulled out of the wreck uninjured and the wrecked
machine--was subsequently placed upon the house-boat, and the
whole brought back to Washington.

From what has been said it will be seen that these unfortunate
accidents have prevented any test of the apparatus in free
flight, and the claim that an engine-driven, man-carrying
aerodrome has been constructed lacks the proof which actual
flight alone can give.

Having reached the present stage of advancement in its
development, it would seem highly desirable, before laying down
the investigation, to obtain conclusive proof of the possibility
of free flight, not only because there are excellent reasons to
hope for success, but because it marks the end of a definite
step toward the attainment of the final goal.

Just what further procedure is necessary to secure successful
flight with the large aerodrome has not yet been decided upon. 
Professor Langley is understood to have this subject under
advisement, and will doubtless inform the Board of his final
conclusions as soon as practicable.

In the meantime, to avoid any possible misunderstanding, it
should be stated that even after a successful test of the
present great aerodrome, designed to carry a man, we are still
far from the ultimate goal, and it would seem as if years of
constant work and study by experts, together with the
expenditure of thousands of dollars, would still be necessary
before we can hope to produce an apparatus of practical utility
on these lines.--Washington, January 6, 1904.

A subsequent report of the Board of ordnance and Fortification
to the Secretary of War embodied the principal points in Major
Macomb's report, but as early as March 3rd, 1904, the Board came
to a similar conclusion to that of the French Ministry of War in
respect of Clement Ader's work, stating that it was not
'prepared to make an additional allotment at this time for
continuing the work.'  This decision was in no small measure due
to hostile newspaper criticisms.  Langley, in a letter to the
press explaining his attitude, stated that he did not wish to
make public the results of his work till these were certain, in
consequence of which he refused admittance to newspaper
representatives, and this attitude produced a hostility which
had effect on the United States Congress.  An offer was made to
commercialise the invention, but Langley steadfastly refused it. 
Concerning this, Manly remarks that Langley had 'given his time
and his best labours to the world without hope of remuneration,
and he could not bring himself, at his stage of life, to consent
to capitalise his scientific work.'

The final trial of the Langley aerodrome was made on December
8th, 1903; nine days later, on December 17th, the Wright
Brothers made their first flight in a power-propelled machine,
and the conquest of the air was thus achieved.  But for the two
accidents that spoilt his trials, the honour which fell to the
Wright Brothers would, beyond doubt, have been secured by Samuel
Pierpoint Langley.



XI.  THE WRIGHT BROTHERS

Such information as is given here concerning the Wright Brothers
is derived from the two best sources available, namely, the
writings of Wilbur Wright himself, and a lecture given by Dr
Griffith Brewer to members of the Royal Aeronautical Society. 
There is no doubt that so far as actual work in connection with
aviation accomplished by the two brothers is concerned, Wilbur
Wright's own statements are the clearest and best available. 
Apparently Wilbur was, from the beginning, the historian of the
pair, though he himself would have been the last to attempt to
detract in any way from the fame that his brother's work also
deserves.  Throughout all their experiments the two were
inseparable, and their work is one indivisible whole; in fact,
in every department of that work, it is impossible to say where
Orville leaves off and where Wilbur begins.

It is a great story, this of the Wright Brothers, and one worth
all the detail that can be spared it.  It begins on the 16th
April, 1867, when Wilbur Wright was born within eight miles of
Newcastle, Indiana.  Before Orville's birth on the 19th August,
1871, the Wright family had moved to Dayton, Ohio, and settled
on what is known as the 'West Side' of the town.  Here the
brothers grew up, and, when Orville was still a boy in his
teens, he started a printing business, which, as  Griffith
Brewer remarks, was only limited by the smallness of his machine
and small quantity of type at his disposal.  This machine was in
such a state that pieces of string and wood were incorporated in
it by way of repair, but on it Orville managed to print a boys'
paper which gained considerable popularity in Dayton 'West
Side.'  Later, at the age of seventeen, he obtained a more
efficient outfit, with which he launched a weekly newspaper,
four pages in size, entitled The West Side News.  After three
months' running the paper was increased in size and Wilbur came
into the enterprise as editor, Orville remaining publisher.  In
1894 the two brothers began the publication of a weekly
magazine, Snap-Shots, to which Wilbur contributed a series of
articles on local affairs that gave evidence of the incisive and
often sarcastic manner in which he was able to express himself
throughout his life.  Dr Griffith Brewer describes him as a
fearless critic, who wrote on matters of local interest in a
kindly but vigorous manner, which did much to maintain the
healthy public municipal life of Dayton.

Editorial and publishing enterprise was succeeded by the
formation, just across the road from the printing works, of the
Wright Cycle Company, where the two brothers launched out as
cycle manufacturers with the 'Van Cleve' bicycle, a machine of
great local repute for excellence of construction, and one which
won for itself a reputation that lasted long after it had ceased
to be manufactured.  The name of the machine was that of an
ancestor of the brothers, Catherine Van Cleve, who was one of
the first settlers at Dayton, landing there from the River Miami
on April 1st, 1796, when the country was virgin forest. 

It was not until 1896 that the mechanical genius which
characterised the two brothers was turned to the consideration
of aeronautics.  In that year they took up the problem
thoroughly, studying all the aeronautical information then in
print.  Lilienthal's writings formed one basis for their
studies, and the work of Langley assisted in establishing in
them a confidence in the possibility of a solution to the
problems of mechanical flight.  In 1909, at the banquet given by
the Royal Aero Club to the Wright Brothers on their return to
America, after the series of demonstration flights carried out
by Wilbur Wright on the Continent, Wilbur paid tribute to the
great pioneer work of Stringfellow, whose studies and
achievements influenced his own and Orville's early work.  He
pointed out how Stringfellow devised an aeroplane having two
propellers and vertical and horizontal steering, and gave due
place to this early pioneer of mechanical flight.

Neither of the brothers was content with mere study of the work
of others.  They collected all the theory available in the books
published up to that time, and then built man-carrying gliders
with which to test the data of Lilienthal and such other
authorities as they had consulted.  For two years they conducted
outdoor experiments in order to test the truth or otherwise of
what were enunciated as the principles of flight; after this
they turned to laboratory experiments, constructing a wind
tunnel in which they made thousands of tests with models of
various forms of curved planes.  From their experiments they
tabulated thousands of readings, which Griffith Brewer remarks
as giving results equally efficient with those of the elaborate
tables prepared by learned institutions. 

Wilbur Wright has set down the beginnings of the practical
experiments made by the two brothers very clearly.  'The
difficulties,' he says, 'which obstruct the pathway to success
in flying machine construction are of three general classes: 
(1) Those which relate to the construction of the sustaining
wings; (2) those which relate to the generation and application
of the power required to drive the machine through the air; (3)
those relating to the balancing and steering of the machine
after it is actually in flight.  Of these difficulties two are
already to a certain extent solved.  Men already know how to
construct wings, or aeroplanes, which, when driven through the
air at sufficient speed, will not only sustain the weight of the
wings themselves, but also that of the engine and the engineer
as well.  Men also know how to build engines and' screws of
sufficient lightness and power to drive these planes at
sustaining speed.  Inability to balance and steer still
confronts students of the flying problem, although nearly ten
years have passed (since Lilienthal's success).  When this one
feature has been worked out, the age of flying machines will
have arrived, for all other difficulties are of minor
importance.

'The person who merely watches the flight of a bird gathers the
impression that the bird has nothing to think of but the
flapping of its wings.  As a matter of fact, this is a very
small part of its mental labour.  Even to mention all the things
the bird must constantly keep in mind in order to fly securely
through the air would take a considerable time.  If I take a
piece of paper and, after placing it parallel with the ground,
quickly let it fall, it will not settle steadily down as a
staid, sensible piece of paper ought to do, but it insists on
contravening every recognised rule of decorum, turning over and
darting hither and thither in the most erratic manner, much
after the style of an untrained horse. Yet this is the style of
steed that men must learn to manage before flying can become an
everyday sport.  The bird has learned this art of equilibrium,
and learned it so thoroughly that its skill is not apparent to
our sight.  We only learn to appreciate it when we can imitate
it.

'Now, there are only two ways of learning to ride a fractious
horse:  one is to get on him and learn by actual practice how
each motion and trick may be best met; the other is to sit on a
fence and watch the beast awhile, and then retire to the house
and at leisure figure out the best way of overcoming his jumps
and kicks.  The latter system is the safer, but the former, on
the whole, turns out the larger proportion of good riders.  It
is very much the same in learning to ride a flying machine; if
you are looking for perfect safety you will do well to sit on a
fence and watch the birds, but if you really wish to learn you
must mount a machine and become acquainted with its tricks by
actual trial.  The balancing of a gliding or flying machine is
very simple in theory.  It merely consists in causing the centre
of pressure to coincide with the centre of gravity.'

These comments are taken from a lecture delivered by Wilbur
Wright before the Western Society of Engineers in September of
1901, under the presidency of Octave Chanute.  In that lecture
Wilbur detailed the way in which he and his brother came to
interest themselves in aeronautical problems and constructed
their first glider. He speaks of his own notice of the death of
Lilienthal in 1896, and of the way in which this fatality roused
him to an active interest in aeronautical problems, which was
stimulated by reading Professor Marey's Animal Mechanism, not
for the first time.  'From this I was led to read more modern
works, and as my brother soon became equally interested with
myself, we soon passed from the reading to the thinking, and
finally to the working stage.  It seemed to us that the main
reason why the problem had remained so long unsolved was that no
one had been able to obtain any adequate practice.  We figured
that Lilienthal in five years of time had spent only about five
hours in actual gliding through the air.  The wonder was not
that he had done so little, but that he had accomplished so
much.  It would not be considered at all safe for a bicycle
rider to attempt to ride through a crowded city street after
only five hours' practice, spread out in bits of ten seconds
each over a period of five years; yet Lilienthal with this brief
practice was remarkably successful in meeting the fluctuations
and eddies of wind-gusts.  We thought that if some method could
be found by which it would be possible to practice by the hour
instead of by the second there would be hope of advancing the
solution of a very difficult problem.  It seemed feasible to do
this by building a machine which would be sustained at a speed
of eighteen miles per hour, and then finding a locality where
winds of this velocity were common.  With these conditions a
rope attached to the machine to keep it from floating backward
would answer very nearly the same purpose as a propeller driven
by a motor, and it would be possible to practice by the hour,
and without any serious danger, as it would not be necessary to
rise far from the ground, and the machine would not have any
forward motion at all.  We found, according to the accepted
tables of air pressure on curved surfaces, that a machine
spreading 200 square feet of wing surface would be sufficient
for our purpose, and that places would easily be found along the
Atlantic coast where winds of sixteen to twenty-five miles were
not at all uncommon.  When the winds were low it was our plan to
glide from the tops of sandhills, and when they were
sufficiently strong to use a rope for our motor and fly over one
spot.  Our next work was to draw up the plans for a suitable
machine.  After much study we finally concluded that tails were
a source of trouble rather than of assistance, and therefore we
decided to dispense with them altogether.  It seemed reasonable
that if the body of the operator could be placed in a horizontal
position instead of the upright, as in the machines of
Lilienthal, Pilcher, and Chanute, the wind resistance could be
very materially reduced, since only one square foot instead of
five would be exposed.  As a full half horse-power would be
saved by this change, we arranged to try at least the horizontal
position.  Then the method of control used by Lilienthal, which
consisted in shifting the body, did not seem quite as quick or
effective as the case required; so, after long study, we
contrived a system consisting of two large surfaces on the
Chanute double-deck plan, and a smaller surface placed a short
distance in front of the main surfaces in such a position that
the action of the wind upon it would counterbalance the effect
of the travel of the centre of pressure on the main surfaces. 
Thus changes in the direction and velocity of the wind would
have little disturbing effect, and the operator would be
required to attend only to the steering of the machine, which
was to be effected by curving the forward surface up or down. 
The lateral equilibrium and the steering to right or left was to
be attained by a peculiar torsion of the main surfaces which was
equivalent to presenting one end of the wings at a greater angle
than the other.  In the main frame a few changes were also made
in the details of construction and trussing employed by Mr
Chanute.  The most important of these were:  (1) The moving of
the forward main crosspiece of the frame to the extreme front
edge; (2) the encasing in the cloth of all crosspieces and ribs
of the surfaces; (3) a rearrangement of the wires used in
trussing the two surfaces together, which rendered it possible
to tighten all the wires by simply shortening two of them.'

The brothers intended originally to get 200 square feet of
supporting surface for their glider, but the impossibility of
obtaining suitable material compelled them to reduce the area to
165 square feet, which, by the Lilienthal tables, admitted of
support in a wind of about twenty-one miles an hour at an angle
of three degrees.  With this glider they went in the summer of I 
1900 to the little settlement of Kitty Hawk, North Carolina,
situated on the strip of land dividing Albemarle Sound from the
Atlantic.  Here they reckoned on obtaining steady wind, and
here, on the day that they completed the machine, they took it
out for trial as a kite with the wind blowing at between
twenty-five and thirty miles an hour.  They found that in order
to support a man on it the glider required an angle nearer
twenty degrees than three, and even with the wind at thirty
miles an hour they could not get down to the planned angle of
three degrees.  'Later, when the wind was too light to support
the machine with a man on it,  they tested it as a kite, working
the rudders by cords. Although they obtained satisfactory
results in this way they realised fully that actual gliding
experience was necessary before the tests could be considered
practical.

A series of actual measurements of lift and drift of the machine
gave astonishing results.  'It appeared that the total
horizontal pull of the machine, while sustaining a weight of 52
lbs., was only 8.5 lbs., which was less than had been previously
estimated for head resistance of the framing alone.  Making
allowance for the weight carried, it appeared that the head
resistance of the framing was but little more than fifty per
cent of the amount which Mr Chanute had estimated as the head
resistance of the framing of his machine.  On the other hand, it
appeared sadly deficient in lifting power as compared with the
calculated lift of curved surfaces of its size... we decided to
arrange our machine for the following year so that the depth of
curvature of its surfaces could be varied at will, and its
covering air-proofed.'

After these experiments the brothers decided to turn to
practical gliding, for which they moved four miles to the south,
to the Kill Devil sandhills, the principal of which is slightly
over a hundred feet in height, with an inclination of nearly ten
degrees on its main north-western slope.  On the day after their
arrival they made about a dozen glides, in which, although the
landings were made at a speed of more than twenty miles an hour,
no injury was sustained either by the machine or by the
operator.

'The slope of the hill was 9.5 degrees, or a drop of one foot in
six.  We found that after attaining a speed of about twenty-five
to thirty miles with reference to the wind, or ten to fifteen
miles over the ground, the machine not only glided parallel to
the slope of the hill, but greatly increased its speed, thus
indicating its ability to glide on a somewhat less angle than
9.5 degrees, when we should feel it safe to rise higher from the
surface.  The control of the machine proved even better than we
had dared to expect, responding quickly to the slightest motion
of the rudder.  With these glides our experiments for the year
1900 closed.  Although the hours and hours of practice we had
hoped to obtain finally dwindled down to about two minutes, we
were very much pleased with the general results of the trip,
for, setting out as we did with almost revolutionary theories on
many points and an entirely untried form of machine, we
considered it quite a point to be able to return without having
our pet theories completely knocked on the head by the hard
logic of experience, and our own brains dashed out in the
bargain. Everything seemed to us to confirm the correctness of
our original opinions:  (1) That practice is the key to the
secret of flying; (2) that it is practicable to assume the
horizontal position; (3) that a smaller surface set at a
negative angle in front of the main bearing surfaces, or wings,
will largely counteract the effect of the fore and aft travel of
the centre of pressure; (4) that steering up and down can be
attained with a rudder without moving the position of the
operator's body; (5) that twisting the wings so as to present
their ends to the wind at different angles is a more prompt and
efficient way of maintaining lateral equilibrium than shifting
the body of the operator.'

For the gliding experiments of 1901 it was decided to retain the
form of the 1900 glider, but to increase the area to 308 square
feet, which, the brothers calculated, would support itself and
its operator in a wind of seventeen miles an hour with an angle
of incidence of three degrees.  Camp was formed at Kitty Hawk in
the middle of July, and on July 27th the machine was completed
and tried for the first time in a wind of about fourteen miles
an hour.  The first attempt resulted in landing after a glide of
only a few yards, indicating that the centre of gravity was too
far in front of the centre of pressure.  By shifting his
position farther and farther back the operator finally achieved
an undulating flight of a little over 300 feet, but to obtain
this success he had to use full power of the rudder to prevent
both stalling and nose-diving. With the 1900 machine one-fourth
of the rudder action had been necessary for far better control.

Practically all glides gave the same result, and in one the
machine rose higher and higher until it lost all headway.  'This
was the position from which Lilienthal had always found
difficulty in extricating himself, as his machine then, in spite
of his greatest exertions, manifested a tendency to dive
downward almost vertically and strike the ground head on with
frightful velocity.  In this case a warning cry from the ground
caused the operator to turn the rudder to its full extent and
also to move his body slightly forward.  The machine then
settled slowly to the ground, maintaining its horizontal
position almost perfectly, and landed without any injury at all. 
This was very encouraging, as it showed that one of the very
greatest dangers in machines with horizontal tails had been
overcome by the use of the front rudder.  Several glides later
the same experience was repeated with the same result.  In the
latter case the machine had even commenced to move backward, but
was nevertheless brought safely to the ground in a horizontal
position.  On the whole this day's experiments were encouraging,
for while the action of the rudder did not seem at all like that
of our 1900 machine, yet we had escaped without difficulty from
positions which had proved very dangerous to preceding
experimenters, and after less than one minute's actual practice
had made a glide of more than 300 feet, at an angle of descent
of ten degrees, and with a machine nearly twice as large as had
previously been considered safe.  The trouble with its control,
which has been mentioned, we believed could be corrected when we
should have located its cause.'

It was finally ascertained that the defect could be remedied by
trussing down the ribs of the whole machine so as to reduce the
depth of curvature.  When this had been done gliding was
resumed, and after a few trials glides of 366 and 389 feet were
made with prompt response on the part of the machine, even to
small movements of the rudder.  The rest of the story of the
gliding experiments of 1901 cannot be better told than in Wilbur
Wright's own words, as uttered by him in the lecture from which
the foregoing excerpts have been made.

'The machine, with its new curvature, never failed to respond
promptly to even small movements of the rudder. The operator
could cause it to almost skim the ground, following the
undulations of its surface, or he could cause it to sail out
almost on a level with the starting point, and, passing high
above the foot of the hill, gradually settle down to the ground. 
The wind on this day was blowing eleven to fourteen miles per
hour.  The next day, the conditions being favourable, the
machine was again taken out for trial.  This time the velocity
of the wind was eighteen to twenty-two miles per hour.  At first
we felt some doubt as to the safety of attempting free flight in
so strong a wind, with a machine of over 300 square feet and a
practice of less than five minutes spent in actual flight.  But
after several preliminary experiments we decided to try a glide. 
The control of the machine seemed so good that we then felt no
apprehension in sailing boldly forth.  And thereafter we made
glide after glide, sometimes following the ground closely and
sometimes sailing high in the air.  Mr Chanute had his camera
with him and took pictures of some of these glides, several of
which are among those shown.

'We made glides on subsequent days, whenever the conditions were
favourable.  The highest wind thus experimented in was a little
over twelve metres per second--nearly twenty-seven miles per
hour.

It had been our intention when building the machine to do the
larger part of the experimenting in the following manner:--When
the wind blew seventeen miles an hour, or more, we would attach
a rope to the machine and let it rise as a kite with the
operator upon it.  When it should reach a proper height the
operator would cast off the rope and glide down to the ground
just as from the top of a hill.  In this way we would be saved
the trouble of carrying the machine uphill after each glide, and
could make at least ten glides in the time required for one in
the other way.  But when we came to try it, we found that a wind
of seventeen miles, as measured by Richards' anemometer, instead
of sustaining the machine with its operator, a total weight of
240 lbs., at an angle of incidence of three degrees, in reality
would not sustain the machine alone--100 lbs.--at this angle. 
Its lifting capacity seemed scarcely one third of the calculated
amount.  In order to make sure that this was not due to the
porosity of the cloth, we constructed two small experimental
surfaces of equal size, one of which was air-proofed and the
other left in its natural state; but we could detect no
difference in their lifting powers.  For a time we were led to
suspect that the lift of curved surfaces very little exceeded
that of planes of the same size, but further investigation and
experiment led to the opinion that (1) the anemometer used by us
over-recorded the true velocity of the wind by nearly 15 per
cent; (2) that the well-known Smeaton co-efficient of .005 V
squared for the wind pressure at 90 degrees is probably too
great by at least 20 per cent; (3) that Lilienthal's estimate
that the pressure on a curved surface having an angle of
incidence of 3 degrees equals .545 of the pressure at go degrees
is too large, being nearly 50 per cent greater than very recent
experiments of our own with a pressure testing-machine indicate;
(4) that the superposition of the surfaces somewhat reduced the
lift per square foot, as compared with a single surface of equal
area.

'In gliding experiments, however, the amount of lift is of less
relative importance than the ratio of lift to drift, as this
alone decides the angle of gliding descent.  In a plane the
pressure is always perpendicular to the surface, and the ratio
of lift to drift is therefore the same as that of the cosine to
the sine of the angle of incidence.  But in curved surfaces a
very remarkable situation is found.  The pressure, instead of
being uniformly normal to the chord of the arc, is usually
inclined considerably in front of the perpendicular.  The result
is that the lift is greater and the drift less than if the
pressure were normal.  Lilienthal was the first to discover this
exceedingly important fact, which is fully set forth in his
book, Bird Flight the Basis of the Flying Art, but owing to some
errors in the methods he used in making measurements, question
was raised by other investigators not only as to the accuracy of
his figures, but even as to the existence of any tangential
force at all.  Our experiments confirm the existence of this
force, though our measurements differ considerably from those of
Lilienthal.  While at Kitty Hawk we spent much time in measuring
the horizontal pressure on our unloaded machine at various
angles of incidence.  We found that at 13 degrees the horizontal
pressure was about 23 lbs.  This included not only the drift
proper, or horizontal component of the pressure on the side of
the surface, but also the head resistance of the framing as
well.  The weight of the machine at the time of this test was
about 108 lbs.  Now, if the pressure had been normal to the
chord of the surface, the drift proper would have been to the
lift (108 lbs.) as the sine of 13 degrees is to the cosine of 13
degrees, or .22 X 108/.97 = 24+ lbs.; but this slightly exceeds
the total pull of 23 pounds on our scales.  Therefore it is
evident that the average pressure on the surface, instead of
being normal to the chord, was so far inclined toward the front
that all the head resistance of framing and wires used in the
construction was more than overcome.  In a wind of fourteen
miles per hour resistance is by no means a negligible factor, so
that tangential is evidently a force of considerable value.  In
a higher wind, which sustained the machine at an angle of 10
degrees the pull on the scales was 18 lbs.  With the pressure
normal to the chord the drift proper would have been 17 X 98/.98.
The travel of the centre of pressure made it necessary to put
sand on the front rudder to bring the centres of gravity and
pressure into coincidence, consequently the weight of the
machine varied from 98 lbs. to 108 lbs. in the different tests)=
17 lbs., so that, although the higher wind velocity must have
caused an increase in the head resistance, the tangential force
still came within 1 lb. of overcoming it.  After our return
from Kitty Hawk we began a series of experiments to accurately
determine the amount and direction of the pressure produced on
curved surfaces when acted upon by winds at the various angles
from zero to 90 degrees.  These experiments are not yet
concluded, but in general they support Lilienthal in the claim
that the curves give pressures more favourable in amount and
direction than planes; but we find marked differences in the
exact values, especially at angles below 10 degrees.  We were
unable to obtain direct measurements of the horizontal pressures
of the machine with the operator on board, but by comparing the
distance travelled with the vertical fall, it was easily
calculated that at a speed of 24 miles per hour the total
horizontal resistances of our machine, when bearing the
operator, amounted to 40 lbs., which is equivalent to about
2 1/3 horse-power.  It must not be supposed, however, that a
motor developing this power would be sufficient to drive a
man-bearing machine.  The extra weight of the motor would
require either a larger machine, higher speed, or a greater
angle of incidence in order to support it, and therefore more
power.  It is probable, however, that an engine of 6
horse-power, weighing 100 lbs.  would answer the purpose.  Such
an engine is entirely practicable.  Indeed, working motors of
one-half this weight per horse-power (9 lbs. per horse-power)
have been constructed by several different builders.  Increasing
the speed of our machine from 24 to 33 miles per hour reduced
the total horizontal pressure from 40 to about 35 lbs.  This was
quite an advantage in gliding, as it made it possible to sail
about 15 per cent farther with a given drop.  However, it would
be of little or no advantage in reducing the size of the motor
in a power-driven machine, because the lessened thrust would be
counterbalanced by the increased speed per minute.  Some years
ago Professor Langley called attention to the great economy of
thrust which might be obtained by using very high speeds, and
from this many were led to suppose that high speed was essential
to success in a motor-driven machine.  But the economy to which
Professor Langley called attention was in foot pounds per mile
of travel, not in foot pounds per minute.  It is the foot pounds
per minute that fixes the size of the motor.  The probability is
that the first flying machines will have a relatively low speed,
perhaps not much exceeding 20 miles per hour, but the problem of
increasing the speed will be much simpler in some respects than
that of increasing the speed of a steamboat; for, whereas in the
latter case the size of the engine must increase as the cube of
the speed, in the flying machine, until extremely high speeds
are reached, the capacity of the motor increases in less than
simple ratio; and there is even a decrease in the fuel per mile
of travel.  In other words, to double the speed of a steamship
(and the same is true of the balloon type of airship) eight
times the engine and boiler capacity would be required, and four
times the fuel consumption per mile of travel:  while a flying
machine would require engines of less than double the size, and
there would be an actual decrease in the fuel consumption per
mile of travel. But looking at the matter conversely, the great
disadvantage of the flying machine is apparent; for in the
latter no flight at all is possible unless the proportion of
horse-power to flying capacity is very high; but on the other
hand a steamship is a mechanical success if its ratio of
horse-power to tonnage is insignificant.  A flying machine that
would fly at a speed of 50 miles per hour with engines of 1,000
horse-power would not be upheld by its wings at all at a speed
of less than 25 miles an hour, and nothing less than 500
horse-power could drive it at this speed.  But a boat which
could make 40 miles an hour with engines of 1,000 horse-power
would still move 4 miles an hour even if the engines were
reduced to 1 horse-power. The problems of land and water travel
were solved in the nineteenth century, because it was possible
to begin with small achievements, and gradually work up to our
present success.  The flying problem was left over to the
twentieth century, because in this case the art must be highly
developed before any flight of any considerable duration at all
can be obtained.

'However, there is another way of flying which requires no
artificial motor, and many workers believe that success will
come first by this road.  I refer to the soaring flight, by
which the machine is permanently sustained in the air by the
same means that are employed by soaring birds.  They spread
their wings to the wind, and sail by the hour, with no
perceptible exertion beyond that required to balance and steer
themselves.  What sustains them is not definitely known, though
it is almost certain that it is a rising current of air.  But
whether it be a rising current or something else, it is as well
able to support a flying machine as a bird, if man once learns
the art of utilising it.  In gliding experiments it has long been
known that the rate of vertical descent is very much retarded,
and the duration of the flight greatly prolonged, if a strong
wind blows UP the face of the hill parallel to its surface.  Our
machine, when gliding in still air, has a rate of vertical
descent of nearly 6 feet per second, while in a wind blowing 26
miles per hour up a steep hill we made glides in which the rate
of descent was less than 2 feet per second. And during the larger
part of this time, while the machine remained exactly in the
rising current, THERE WAS NO DESCENT AT ALL, BUT EVEN A SLIGHT
RISE.   If the operator had had sufficient skill to keep himself
from passing beyond the rising current he would have been
sustained indefinitely at a higher point than that from which he
started.  The illustration shows one of these very slow glides at
a time when the machine was practically at a standstill.  The
failure to advance more rapidly caused the photographer some
trouble in aiming, as you will perceive.  In looking at this
picture you will readily understand that the excitement of
gliding experiments does not entirely cease with the breaking up
of camp.  In the photographic dark-room at home we pass moments
of as thrilling interest as any in the field, when the image
begins to appear on the plate and it is yet an open question
whether we have a picture of a flying machine or merely a patch
of open sky.  These slow glides in rising current probably hold
out greater hope of extensive practice than any other method
within man's reach, but they have the disadvantage of requiring
rather strong winds or very large supporting surfaces.  However,
when gliding operators have attained greater skill, they can with
comparative safety maintain themselves in the air for hours at a
time in this way, and thus by constant practice so increase
their knowledge and skill that they can rise into the higher air
and search out the currents which enable the soaring birds to
transport themselves to any desired point by first rising in a
circle and then sailing off at a descending angle.  This
illustration shows the machine, alone, flying in a wind of 35
miles per hour on the face of a steep hill, 100 feet high. It
will be seen that the machine not only pulls upward, but also
pulls forward in the direction from which the wind blows, thus
overcoming both gravity and the speed of the wind.  We tried the
same experiment with a man on it, but found danger that the
forward pull would become so strong, that the men holding the
ropes would be dragged from their insecure foothold on the slope
of the hill.  So this form of experimenting was discontinued
after four or five minutes' trial.

'In looking over our experiments of the past two years, with
models and full-size machines, the following points stand out
with clearness:--

'1.  That the lifting power of a large machine, held stationary
in a wind at a small distance from the earth, is much less than
the Lilienthal table and our own laboratory experiments would
lead us to expect.  When the machine is moved through the air,
as in gliding, the discrepancy seems much less marked.

'2.  That the ratio of drift to lift in well-shaped surfaces is
less at angles of incidence of 5 degrees to 12 degrees than at
an angle of 3 degrees.

'3.  That in arched surfaces the centre of pressure at 90
degrees is near the centre of the surface, but moves slowly
forward as the angle becomes less, till a critical angle varying
with the shape and depth of the curve is reached, after which it
moves rapidly toward the rear till the angle of no lift is
found.

'4.  That with similar conditions large surfaces may be
controlled with not much greater difficulty than small ones, if
the control is effected by manipulation of the surfaces
themselves, rather than by a movement of the body of the
operator.

'5.  That the head resistances of the framing can be brought to
a point much below that usually estimated as necessary.

'6.  That tails, both vertical and horizontal, may with safety
be eliminated in gliding and other flying experiments.

'7.  That a horizontal position of the operator's body may be
assumed without excessive danger, and thus the head resistance
reduced to about one-fifth that of the upright position.

'8.  That a pair of superposed, or tandem surfaces, has less
lift in proportion to drift than either surface separately, even
after making allowance for weight and head resistance of the
connections.'

Thus, to the end of the 1901 experiments, Wilbur Wright provided
a fairly full account of what was accomplished; the record shows
an amount of patient and painstaking work almost beyond
belief--it was no question of making a plane and launching it,
but a business of trial and error, investigation and tabulation
of detail, and the rejection time after time of previously
accepted theories, till the brothers must have felt the the
solid earth was no longer secure, at times.  Though it was
Wilbur who set down this and other records of the work done,
yet the actual work was so much Orville's as his brother's that
no analysis could separate any set of experiments and say that
Orville did this and Wilbur that--the two were inseparable.  On
this point Griffith Brewer remarked that 'in the arguments, if
one brother took one view, the other brother took the opposite
view as a matter of course, and the subject was thrashed to
pieces until a mutually acceptable result remained.  I have
often been asked since these pioneer days, "Tell me, Brewer, who
was really the originator of those two?" In reply, I used
first to say, "I think it was mostly  Wilbur," and later,
when I came to know Orville better, I said, "The thing could not
have been without Orville."  Now, when asked, I have to say, " I
don't know," and I feel the more I think of it that it was only
the wonderful combination of these two brothers, who devoted
their lives together or this common object, that made the
discovery of the art of flying possible.'

Beyond the 1901 experiments in gliding, the record grows more
scrappy, less detailed.  It appears that once power-driven
flight had been achieved, the brothers were not so willing to
talk as before; considering the amount of work that they put in,
there could have been  little time for verbal description
of that work--as already  remarked, their tables still stand for
the designer and experimenter.  The end of the 1901 experiments
left both brothers somewhat discouraged, though they had
accomplished more than any others.  'Having set out with
absolute faith in the existing scientific data, we ere driven to
doubt one thing after another, finally, after two years of
experiment, we cast it all aside, and decided to rely entirely
on our own investigations.  Truth and error were everywhere so
in,timately mixed as to be indistinguishable.... We had taken up
aeronautics as a sport.  We reluctantly entered upon the
scientific side of it.'

Yet, driven thus to the more serious aspect of the work, they
found in the step its own reward, for the work of itself drew
them on and on, to the construction of measuring machines for
the avoidance of error, and to the making of series after series
of measurements, concerning which Wilbur wrote in 1908 (in the
Century Magazine) that 'after making preliminary measurements on
a great number of different shaped surfaces, to secure a general
understanding of the subject, we began systematic measurements
of standard surfaces, so varied in design as to bring out the
underlying causes of  differences noted in their pressures. 
Measurements were tabulated on nearly fifty of these at all
angles from zero to 45 degrees, at intervals of 2 1/2 degrees. 
Measurements were also secured showing the effects on each other
when surfaces are superposed, or when they follow one another.

'Some strange results were obtained.  One surface, with a heavy
roll at the front edge, showed the same lift for all angles from
7 1/2 to 45 degrees.  This seemed so anomalous that we were
almost ready to doubt our own measurements, when a simple test
was suggested.  A weather vane, with two planes attached to the
pointer at an angle of 80 degrees with each other, was made.
According to our table, such a vane would be in unstable
equilibrium when pointing directly into the wind, for if by
chance the wind should happen to strike one plane at 39 degrees
and the other at 41 degrees, the plane with the smaller angle
would have the greater pressure and the pointer would be turned
still farther out of the course of the wind until the two vanes
again secured equal pressures, which would be at approximately
30 and 50 degrees.  But the vane performed in this very manner. 
Further corroboration of the tables was obtained in experiments
with the new glider at Kill Devil Hill the next season.

'In September and October, 1902 nearly 1,000 gliding flights
were made, several of which covered distances of over 600 feet. 
Some, made against a wind of 36 miles an hour, gave proof of the
effectiveness of the devices for control.  With this machine, in
the autumn of 1903, we made a number of flights in which we
remained in the air for over a minute, often soaring for a
considerable time in one spot, without any descent at all. 
Little wonder that our unscientific assistant should think the
only thing needed to keep it indefinitely in the air would be a
coat of feathers to make it light! '

It was at the conclusion of these experiments of 1903 that the
brothers concluded they had obtained sufficient data from their
thousands of glides and multitude of calculations to permit of
their constructing and making trial of a power-driven machine. 
The first designs got out provided for a total weight of 600
lbs., which was to include the weight of the motor and the
pilot; but on completion it was found that there was a surplus
of power from the motor, and thus they had 150 lbs. weight to
allow for strengthening wings and other parts. 

They came up against the problem to which Riach has since
devoted so much attention, that of propeller design. 'We had
thought of getting the theory of the screw-propeller from the
marine engineers, and then, by applying our table of
air-pressures to their formulae, of designing air-propellers
suitable for our uses.  But, so far as we could learn, the
marine engineers possessed only empirical formulae, and the
exact action of the screw propeller, after a century of use, was
still very obscure.  As we were not in a position to undertake a
long series of practical experiments to discover a propeller
suitable for our machine, it seemed necessary to obtain such a
thorough understanding of the theory of its reactions as would
enable us to design them from calculation alone.  What at first
seemed a simple problem became more complex the longer we
studied it.  With the machine moving forward, the air flying
backward, the propellers turning sidewise, and nothing standing
still, it seemed impossible to find a starting point from which
to trace the various simultaneous reactions.  Contemplation of
it was confusing.  After long arguments we often found ourselves
in the ludicrous position of each having been converted to the
other's side, with no more agreement than when the discussion
began.

'It was not till several months had passed, and every phase of
the problem had been thrashed over and over, that the various
reactions began to untangle themselves.  When once a clear
understanding had been obtained there was no difficulty in
designing a suitable propeller, with proper diameter, pitch, and
area of blade, to meet the requirements of the flier.  High
efficiency in a screw-propeller is not dependent upon any
particular or peculiar shape, and there is no such thing as a
"best" screw.  A propeller giving a high dynamic efficiency when
used upon one machine may be almost worthless when used upon
another.  The propeller should in every case be designed to meet
the particular conditions of the machine to which it is to be
applied.  Our first propellers, built entirely from calculation,
gave in useful work 66 per cent of the power expended.  This was
about one-third more than had been secured by Maxim or Langley.'

Langley had made his last attempt with the 'aerodrome,' and his
splendid failure but a few days before the brothers made their
first attempt at power-driven aeroplane flight.  On December
17th, 1903, the machine was taken out; in addition to Wilbur and
Orville Wright, there were present five spectators:  Mr A. D.
Etheridge, of the Kil1 Devil life-saving station; Mr W. S.Dough,
Mr W. C. Brinkley, of Manteo; Mr John Ward, of Naghead, and Mr
John T. Daniels.[*] A general invitation had been given to
practically all the residents in the vicinity, but the Kill
Devil district is a cold area in December, and history had
recorded so many experiments in which machines had failed to
leave the ground that between temperature and scepticism only
these five risked a waste of their time.

[*] This list is as given by Wilbur Wright himself.

And these five were in at the greatest conquest man had made
since James Watt evolved the steam engine --perhaps even a
greater conquest than that of Watt.  Four flights in all were
made; the first lasted only twelve seconds, 'the first in the
history of the world in which a machine carrying a man had
raised itself into the air by its own power in free flight, had
sailed forward on a level course without reduction of speed, and
had finally landed without being wrecked,' said Wilbur
Wright concerning the achievement.[*] The next two flights were
slightly longer, and the fourth and last of the day was one
second short of the complete  minute; it was made into the teeth
of a 20 mile an hour wind, and the distance travelled was 852
feet.

[*] Century Magazine, September, 1908.

This bald statement of the day's doings is as Wilbur Wright
himself has given it, and there is in truth nothing more to say;
no amount of statement could add to the importance of the
achievement, and no more than the bare record is necessary.  The
faith that had inspired the long roll of pioneers, from da Vinci
onward, was justified at last.

Having made their conquest, the brothers took the machine back
to camp, and, as they thought, placed it in safety.  Talking
with the little group of spectators about the flights, they
forgot about the machine, and then a sudden gust of wind struck
it.  Seeing that it was being overturned, all made a rush toward
it to save it, and Mr Daniels, a man of large proportions, was
in some way lifted off his feet, falling between the planes. 
The machine overturned fully, and Daniels was shaken like a die
in a cup as the wind rolled the machine over and over--he came
out at the end of his experience with a series of bad bruises,
and no more, but the damage done to the machine by the accident
was sufficient to render it useless for further experiment that
season.

A new machine, stronger and heavier, was constructed by the
brothers, and in the spring of 1904 they began experiments again
at Sims Station, eight miles to the east of Dayton, their home
town.  Press representatives were invited for the first trial,
and about a dozen came--the whole gathering did not number more
than fifty people.  'When preparations had been concluded,'
Wilbur Wright wrote of this trial, 'a wind of only three or four
miles an hour was blowing--insufficient for starting on so short
a track --but since many had come a long way to see the machine
in action, an attempt was made.  To add to the other difficulty,
the engine refused to work properly.  The machine, after running
the length of the track, slid off the end without rising into
the air at all.  Several of the newspaper men returned next day
but were again disappointed.  The engine performed badly, and
after a glide of only sixty feet the machine again came to the
ground.  Further trial was postponed till the motor could be put
in better running condition.  The reporters had now, no doubt,
lost confidence in the machine, though their reports, in
kindness, concealed it.  Later, when they heard that we were
making flights of several minutes' duration, knowing that longer
flights had been made with airships, and not knowing any
essential difference between airships and flying machines, they
were but little interested.

'We had not been flying long in 1904 before we found that the
problem of equilibrium had not as yet been entirely solved. 
Sometimes, in making a circle, the machine would turn over
sidewise despite anything the operator could do, although, under
the same conditions in ordinary straight flight it could have
been righted in an instant.  In one flight, in 1905, while
circling round a honey locust-tree at a height of about 50 feet,
the machine suddenly began to turn up on one wing, and took a
course toward the tree.  The operator, not relishing the idea of
landing in a thorn tree, attempted to reach the ground.  The
left wing, however, struck the tree at a height of 10 or 12 feet
from the ground and carried away several branches; but the
flight, which had already covered a distance of six miles, was
continued to the starting point.

'The causes of these troubles--too technical for explanation
here--were not entirely overcome till the end of September,
1905.  The flights then rapidly increased in length, till
experiments were discontinued after October 5 on account of the
number of people attracted to the field. Although made on a
ground open on every side, and bordered on two sides by
much-travelled thoroughfares, with electric cars passing every
hour, and seen by all the people living in the neighbourhood for
miles around, and by several hundred others, yet these flights
have been made by some newspapers the subject of a great
"mystery." '

Viewing their work from the financial side, the two brothers
incurred but little expense in the earlier gliding experiments,
and, indeed, viewed these only as recreation, limiting their
expenditure to that which two men might spend on any hobby. 
When they had once achieved successful power-driven flight, they
saw the possibilities of their work, and abandoned such other
business as had engaged their energies, sinking all their
capital in the development of a practical flying machine. 
Having, in 1905, improved their designs to such an extent that
they could consider their machine a practical aeroplane, they
devoted the years 1906 and 1907 to business negotiations and to
the construction of new machines, resuming flying experiments in
May of 1908 in order to test the ability of their machine to
meet the requirements of a contract they had made with the
United States Government, which required an aeroplane capable of
carrying two men, together with sufficient fuel supplies for a
flight of 125 miles at 40 miles per hour.  Practically similar
to the machine used in the experiments of 1905, the contract
aeroplane was fitted with a larger motor, and provision was made
for seating a passenger and also for allowing of the operator
assuming a sitting position, instead of lying prone.

Before leaving the work of the brothers to consider contemporary
events, it may be noted that they claimed--with justice--that
they were first to construct wings adjustable to different
angles of incidence on the right and left side in order to
control the balance of an aeroplane; the first to attain lateral
balance by adjusting wing-tips to respectively different angles
of incidence on the right and left sides, and the first to use a
vertical vane in combination with wing-tips, adjustable to
respectively different angles of incidence, in balancing and
steering an aeroplane.  They were first, too, to use a movable
vertical tail, in combination with wings adjustable to different
angles of incidence, in controlling the balance and direction of
an aeroplane.[*]

[*]Aeronautical Journal, No. 79.

A certain Henry M. Weaver, who went to see the work of the
brothers, writing in a letter which was subsequently read before
the Aero Club de France records that he had a talk in 1905 with
the farmer who rented the field in which the Wrights made their
flights.' On October 5th (1905) he was cutting corn in the next
field east, which is higher ground.  When he noticed the
aeroplane had started on its flight he remarked to his helper: 
"Well, the boys are at it again," and kept on cutting corn, at
the same time keeping an eye on the great white form rushing
about its course.  "I just kept on shocking corn," he continued,
"until I got down to the fence, and the durned thing was still
going round.  I thought it would never stop." '

He was right.  The brothers started it, and it will never stop.

Mr Weaver also notes briefly the construction of the 1905 Wright
flier.  'The frame was made of larch wood-from tip to tip of the
wings the dimension was 40 feet.  The gasoline motor--a special
construction made by them--much the same, though, as the motor
on the Pope-Toledo automobile--was of from 12 to 15 horse-power. 
The motor weighed 240 lbs.  The frame was covered with ordinary
muslin of good quality.  No attempt was made to lighten the
machine; they simply built it strong enough to stand the shocks. 
The structure stood on skids or runners, like a sleigh.  These
held the frame high enough from the ground in alighting to
protect the blades of the propeller. Complete with motor, the
machine weighed 925 lbs.



XII. THE FIRST YEARS OF CONQUEST

It is no derogation of the work accomplished by the Wright
Brothers to say that they won the honour of the first
power-propelled flights in a heavier-than-air machine only by a
short period.  In Europe, and especially in France, independent
experiment was being conducted by Ferber, by Santos-Dumont, and
others, while in England Cody was not far behind the other
giants of those days.  The history of the early years of
controlled power flights is a tangle of half-records; there were
no chroniclers, only workers, and much of what was done goes
unrecorded perforce, since it was not set down at the time.

Before passing to survey of those early years, let it be set
down that in 1907, when the Wright Brothers had proved the
practicability of their machines, negotiations were entered into
between the brothers and the British War office.  On April 12th
1907, the apostle of military stagnation, Haldane, then War
Minister, put an end to the negotiations by declaring that 'the
War office is not disposed to enter into relations at present
with any manufacturer of aeroplanes' The state of the British
air service in 1914 at the outbreak of hostilities, is eloquent
regarding the pursuance of the  policy which Haldane initiated.

'If I talked a lot,' said Wilbur Wright once, 'I should be like
the parrot, which is the bird that speaks most and flies least.'
That attitude is emblematic of the majority of the early fliers,
and because of it the record of their achievements is incomplete
to-day.  Ferber, for instance, has left little from which to
state what he did, and that little is scattered through various
periodicals, scrappily enough.  A French army officer, Captain
Ferber was experimenting with monoplane and biplane gliders at
the beginning of the century-his work was contemporary with that
of the Wrights.  He corresponded both with Chanute and with the
Wrights, and in the end he was commissioned by the French
Ministry of War to undertake the journey to America in order to
negotiate with the Wright Brothers concerning French rights in
the patents they had acquired, and to study their work at first
hand.

Ferber's experiments in gliding began in 1899 at the Military
School at Fountainebleau, with a canvas glider of some 80 square
feet supporting surface, and weighing 65 lbs.  Two years later
he constructed a larger and more satisfactory machine, with
which he made numerous excellent glides.  Later, he constructed
an apparatus which suspended a plane from a long arm which swung
on a tower, in order that experiments might be carried out
without risk to the experimenter, and it was not until 1905 that
he attempted power-driven free flight.  He took up the Voisin
design of biplane for his power-driven flights, and virtually
devoted all his energies to the study of aeronautics.  His book,
Aviation, its Dawn and Development, is a work of scientific
value--unlike many of his contemporaries, Ferber brought to the
study of the problems of flight a trained mind, and he was
concerned equally  with the theoretical problems of aeronautics
and the practical aspects of the subject.

After Bleriot's successful cross-Channel flight, it was proposed
to offer a prize of L1,000 for the feat which C. S. Rolls
subsequently accomplished (starting from the English side of the
Channel), a flight from Boulogne to Dover and back; in place of
this, however, an aviation week at Boulogne was organised, but,
although numerous aviators were invited to compete, the
condition of the flying grounds was such that no competitions
took place.  Ferber was virtually the only one to do any flying
at Boulogne, and at the outset he had his first accident; after
what was for those days a good flight, he made a series of
circles with his machine, when it suddenly struck the ground,
being partially wrecked.  Repairs were carried out, and Ferber
resumed his exhibition flights, carrying on up to Wednesday,
September 22nd, 1909.  On that day he remained in the air for
half an hour, and, as he was about to land, the machine struck a
mound of earth and overturned, pinning Ferber under the weight
of the motor.  After being extricated, Ferber seemed to show
little concern at the accident, but in a few minutes he
complained of great pain, when he was conveyed to the ambulance
shed on the ground.

'I was foolish,' he told those who were with him there.  'I was
flying too low.  It was my own fault and it will be a severe
lesson to me.  I wanted to turn round, and was only five metres
from the ground.'  A little after this, he got up from the couch
on which he had been placed, and almost immediately collapsed,
dying five minutes later.

Ferber's chief contemporaries in France were Santos-Dumont, of
airship fame, Henri and Maurice Farman, Hubert Latham, Ernest
Archdeacon, and Delagrange.  These are names that come at once to
mind, as does that of Bleriot, who accomplished the second great
feat of power-driven flight, but as a matter of fact the years
1903-10 are filled with a little host of investigators and
experimenters, many of whom, although their names do not survive
to any extent, are but a very little way behind those mentioned
here in enthusiasm and devotion.  Archdeacon and Gabriel Voisin,
the former of whom took to heart the success achieved by the
Wright Brothers, co-operated in experiments in gliding. 
Archdeacon constructed a glider in box-kite fashion, and Voisin
experimented with it on the Seine, the glider being towed by a
motorboat to attain the necessary speed.  It was Archdeacon who
offered a cup for the first straight flight of 200 metres, which
was won by Santos-Dumont, and he also combined with Henri Deutsch
de la Meurthe in giving the prize for the first circular flight
of a mile, which was won by Henry Farman on January 13th, 1908.

A history of the development of aviation in France in these, the
strenuous years, would fill volumes in itself.  Bleriot was
carrying out experiments with a biplane glider on the Seine, and
Robert Esnault-Pelterie was working on the lines of the Wright
Brothers, bringing American practice to France.  In America
others besides the Wrights had wakened to the possibilities of
heavier-than-air flight; Glenn Curtiss, in company with Dr
Alexander Graham Bell, with J. A. D. McCurdy, and with F. W.
Baldwin, a Canadian engineer, formed the Aerial Experiment
Company, which built a number of aeroplanes, most famous of
which were the 'June Bug,' the 'Red Wing,' and the 'White Wing.'
In 1908 the 'June Bug 'won a cup presented by the Scientific
American--it was the first prize offered in America in
connection with aeroplane flight.

Among the little group of French experimenters in these first
years of practical flight, Santos-Dumont takes high rank.  He
built his 'No. 14 bis' aeroplane in biplane form, with two
superposed main plane surfaces, and fitted it with an
eight-cylinder Antoinette motor driving a two-bladed aluminium
propeller, of which the blades were 6 feet only from tip to tip. 
The total lift surface of 860 square feet was given with a
wing-span of a little under 40 feet, and the weight of the
complete machine was 353 lbs., of which the engine weighed 158
lbs.  In July of 1906 Santos-Dumont flew a distance of a few
yards in this machine, but damaged it in striking the ground; on
October 23rd of the same year he made a flight of nearly 200
feet--which might have been longer, but that he feared a crowd
in front of the aeroplane and cut off his ignition.  This may be
regarded as the first effective flight in Europe, and by it
Santos-Dumont takes his place as one of the chief--if not the
chief--of the pioneers of the first years of practical flight,
so far as Europe is concerned.

Meanwhile, the Voisin Brothers, who in 1904 made cellular kites
for Archdeacon to test by towing on the Seine from a motor
launch, obtained data for the construction of the aeroplane
which Delagrange and Henry Farman were to use later.  The Voisin
was a biplane, constructed with due regard to the designs of
Langley, Lilienthal, and other earlier experimenters--both the
Voisins and M. Colliex, their engineer, studied Lilienthal
pretty exhaustively in getting out their design, though their
own researches were very thorough as well.  The weight of this
Voisin biplane was about 1,450 lbs., and its maximum speed was
some 38 to 40 miles per hour, the total supporting surface being
about 535 square feet.  It differed from the Wright design in
the possession of a tail-piece, a characteristic which marked
all the French school of early design as in opposition to the
American.  The Wright machine got its longitudinal stability by
means of the main planes and the elevating planes, while the
Voisin type added a third factor of stability in its sailplanes.
Further, the Voisins fitted their biplane with a wheeled
undercarriage, while the Wright machine, being fitted only with
runners, demanded a launching rail for starting.  Whether a
machine should be tailless or tailed was for some long time
matter for acute controversy, which in the end was settled by
the fitting of a tail to the Wright machines-France won the
dispute by the concession.

Henry Farman, who began his flying career with a Voisin machine,
evolved from it the aeroplane which bore his name, following the
main lines of the Voisin type fairly closely, but making
alterations in the controls, and in the design of the
undercarriage, which was somewhat elaborated, even to the
inclusion of shock absorbers.  The seven-cylinder 50 horse-power
Gnome rotary engine was fitted to the Farman machine--the
Voisins had fitted an eight-cylinder Antoinette, giving 50
horse-power at 1,100 revolutions per minute, with direct drive
to the propeller.  Farman reduced the weight of the machine from
the 1,450 lbs. of the Voisins to some 1,010 lbs. or
thereabouts, and the supporting area to 450 square feet.  This
machine won its chief fame with Paulhan as pilot in the famous
London to Manchester flight--it is to be remarked, too, that
Farman himself was the first man in Europe to accomplish a
flight of a mile.

Other notable designs of these early days were the 'R.E.P.',
Esnault Pelterie's machine, and the Curtiss-Herring biplane.  Of
these Esnault Pelterie's was a monoplane, designed in that form
since Esnault Pelterie had found by experiment that the wire
used in bracing offers far more resistance to the air than its
dimensions would seem to warrant.  He built the wings of
sufficient strength to stand the strain of flight without
bracing wires, and dependent only for their support on the
points of attachment to the body of the machine; for the rest,
it carried its propeller in front of the planes, and both
horizontal and vertical rudders at the stern--a distinct
departure from the Wright and similar types.  One wheel only was
fixed under the body where the undercarriage exists on a normal
design, but light wheels were fixed, one at the extremity of
each wing, and there was also a wheel under the tail portion of
the machine.  A single lever actuated all the controls for
steering.  With a supporting surface of 150 square feet the
machine weighed 946 lbs., about 6.4 lbs. per square foot of
lifting surface.

The Curtiss biplane, as flown by Glenn Curtiss at the Rheims
meeting, was built with a bamboo framework, stayed by means of
very fine steel-stranded cables.  A--then--novel feature of the
machine was the moving of the ailerons by the pilot leaning to
one side or the other in his seat, a light, tubular arm-rest
being pressed  by his body when he leaned to one side or the
other, and thus operating the movement of the ailerons employed
for tilting the plane when turning.  A steering-wheel fitted
immediately in front of the pilot's seat served to operate a
rear steering-rudder when the wheel was turned in either
direction, while pulling back the wheel altered the inclination
of the front elevating planes, and so gave lifting or depressing
control of the plane.

This machine ran on three wheels before leaving the ground, a
central undercarriage wheel being fitted in front, with two more
in line with a right angle line drawn through the centre of the
engine crank at the rear end of the crank-case.  The engine was
a  35 horsepower Vee design, water cooled, with overhead inlet
and exhaust valves, and Bosch high-tension magneto ignition. 
The total weight of the plane in flying order was about 700 lbs.

As great a figure in the early days as either Ferber or
Santos-Dumont was Louis Bleriot, who, as early as 1900 built a
flapping-wing model, this before ever he came to experimenting
with the Voisin biplane type of glider on the Seine.  Up to 1906
he had built four biplanes of his own design, and in March of
1907 he built his first monoplane, to wreck it only a few days
after completion in an accident from which he had a fortunate
escape.  His next machine was a double monoplane, designed after
Langley's precept, to a certain extent, and this was totally
wrecked in September of 1907.  His seventh machine, a
monoplane, was built within a month of this accident, and with
this he had a number of mishaps, also achieving some good
flights, including one in which he made a turn.  It was wrecked
in December of 1907, whereupon he built another monoplane on
which, on July 6th, 1908, Bleriot made a flight lasting eight
and a half minutes.  In October of that year he flew the machine
from Toury to Artenay and returned on it--this was just a day
after Farman's first cross-country flight--but, trying to repeat
the success five days later, Bleriot collided with a tree in a
fog and wrecked the machine past repair.  Thereupon he set about
building his eleventh machine, with which he was to achieve the
first flight across the English channel.

Henry Farman, to whom reference has already been made, was
engaged with his two brothers, Maurice and Richard, in the
motor-car business, and turned to active interest in flying in
1907, when the Voisin firm built his first biplane on the
box-kite principle.  In July of 1908 he won a prize of L400 for
a flight of thirteen miles, previously having completed the
first kilometre flown in Europe with a passenger, the said
passenger being Ernest Archdeaon. In September of 1908 Farman
put up a speed record of forty miles an hour in a flight lasting
forty minutes.

Santos-Dumont produced the famous 'Demoiselle' monoplane early
in 1909, a tiny machine in which the pilot had his seat in a
sort of miniature cage under the main plane.  It was a very
fast, light little machine but was difficult to fly, and owing
to its small wingspread was unable to glide at a reasonably safe
angle.  There has probably never been a cheaper flying machine
to build than the 'Demoiselle,' which could be so upset as to
seem completely wrecked, and then repaired ready for further
flight by a couple of hours' work.  Santos-Dumont retained no
patent in the design, but gave it out freely to any one who
chose to build 'Demoiselles'; the vogue of the pattern was
brief, owing to the difficulty of piloting the machine.

These were the years of records, broken almost as soon as made. 
There was Farman's mile, there was the flight of the Comte de
Lambert over the Eiffel Tower, Latham's flight at Blackpool in a
high wind, the Rheims records, and then Henry Farman's flight of
four hours later in 1909, Orville Wright's height record of
1,640 feet, and Delagrange's speed record of 49.9 miles per
hour.  The coming to fame of the Gnome rotary engine helped in
the making of these records to a very great extent, for in this
engine was a prime mover which gave the reliability that
aeroplane builders and pilots had been searching for, but
vainly.  The Wrights and Glenn Curtiss, of course, had their own
designs of engine, but the Gnome, in spite of its lack of
economy in fuel and oil, and its high cost, soon came to be
regarded as the best power plant for flight.

Delagrange, one of the very good pilots of the early days,
provided a curious insight to the way in which flying was
regarded, at the opening of the Juvisy aero aerodrome in May of
1909.  A huge crowd had gathered for the first day's flying, and
nine machines were announced to appear, but only three were
brought out.  Delagrange made what was considered an indifferent
little flight, and another pilot, one De Bischoff, attempted to
rise, but could not get his machine off the ground.  Thereupon
the crowd of 30,000 people lost their tempers, broke down the
barriers surrounding the flying course, and hissed the
officials, who were quite unable to maintain order. Delagrange,
however, saved the situation by making a circuit of the course
at a height of thirty feet from the ground, which won him rounds
of cheering and restored the crowd to good humour.  Possibly the
smash achieved by Rougier, the famous racing motorist, who
crashed his Voisin biplane after Delagrange had made his
circuit, completed the enjoyment of the spectators.  Delagrange,
flying at Argentan in June of 1909, made a flight of four
kilometres at a height of sixty feet; for those days this was a
noteworthy performance.  Contemporary with this was Hubert
Latham's flight of an hour and seven minutes on an Antoinette
monoplane; this won the adjective 'magnificent' from
contemporary recorders of aviation.

Viewing the work of the little group of French experimenters, it
is, at this length of time from their exploits, difficult to see
why they carried the art as far as they did.  There was in it
little of satisfaction, a certain measure of fame, and
practically no profit--the giants of those days got very little
for their pains.  Delagrange's experience at the opening of the
Juvisy ground was symptomatic of the way in which flight was
regarded by the great mass of people--it was a sport, and
nothing more, but a sport without the dividends attaching to
professional football or horse-racing.  For a brief period,
after the Rheims meeting, there was a golden harvest to be
reaped by the best of the pilots.  Henry Farman asked L2,000 for
a week's exhibition flying in England, and Paulhan asked half
that sum, but a rapid increase in the number of capable pilots,
together with the fact that most flying meetings were financial
failures, owing to great expense in organisation and the
doubtful factor of the weather, killed this goose before many
golden eggs had been gathered in by the star aviators.  Besides,
as height and distance records were broken one after another, it
became less and less necessary to pay for entrance to an
aerodrome in order to see a flight--the thing grew too big for a
mere sports ground.

Long before Rheims and the meeting there, aviation had grown too
big for the chronicling of every individual effort. In that
period of the first days of conquest of the air, so much was
done by so many whose names are now half-forgotten that it is
possible only to pick out the great figures and make brief
reference to their achievements and the machines with which they
accomplished so much, pausing to note such epoch-making events
as the London-Manchester flight, Bleriot's Channel crossing, and
the Rheims meeting itself, and then passing on beyond the days
of individual records to the time when the machine began to
dominate the man.  This latter because, in the early days, it
was heroism to trust life to the planes that were turned out
--the 'Demoiselle' and the Antoinette machine that Latham used
in his attempt to fly the Channel are good examples of the
flimsiness of early types--while in the later period, that of
the war and subsequently, the heroism turned itself in a
different--and nobler-direction.  Design became standardised,
though not perfected.  The domination of the machine may best be
expressed by contrasting the way in which machines came to be
regarded as compared with the men who flew them:  up to 1909,
flying enthusiasts talked of Farman, of Bleriot, of Paulhan,
Curtiss, and of other men; later, they began to talk of the
Voisin, the Deperdussin, and even to the Fokker, the Avro, and
the Bristol type.  With the standardising of the machine, the
days of the giants came to an end.



XIII. FIRST FLIERS IN ENGLAND

Certain experiments made in England by Mr Phillips seem to have
come near robbing the Wright Brothers of the honour of the first
flight; notes made by Colonel J. D. Fullerton on the Phillips
flying machine show that in 1893 the first machine was built
with a length of 25 feet, breadth of 22 feet, and height of 11
feet, the total weight, including a 72 lb. load, being 420 lbs. 
The machine was fitted with some fifty wood slats, in place of
the single supporting surface of the monoplane or two superposed
surfaces of the biplane, these slats being fixed in a steel
frame so that the whole machine rather resembled a Venetian
blind.  A steam engine giving about 9 horse-power provided the
motive power for the six-foot diameter propeller which drove the
machine.  As it was not possible to put a passenger in control
as pilot, the machine was attached to a central post by wire
guys and run round a circle 100 feet in diameter, the track
consisting of wooden planking 4 feet wide.  Pressure of air
under the slats caused the machine to rise some two or three
feet above the track when sufficient velocity had been attained,
and the best trials were made on June 19th 1893, when at a speed
of 40 miles an hour, with a total load of 385 lbs., all the
wheels were off the ground for a distance of 2,000 feet.

In 1904 a full-sized machine was constructed by Mr Phillips,
with a total weight, including that of the pilot, of 600 lbs. 
The machine was designed to lift when it had attained a velocity
of 50 feet per second, the motor fitted giving 22 horse-power. 
On trial, however, the longitudinal equilibrium was found to be
defective, and a further design was got out, the third machine
being completed in 1907.  In this the wood slats were held in
four parallel container frames, the weight of the machine,
excluding the pilot, being 500 lbs.  A motor similar to that
used in the 1904 machine was fitted, and the machine was
designed to lift at a velocity of about 30 miles an hour, a
seven-foot propeller doing the driving.  Mr Phillips tried out
this machine in a field about 400 yards across.  'The machine
was started close to the hedge, and rose from the ground when
about 200 yards had been covered.  When the machine touched the
ground again, about which there could be no doubt, owing to the
terrific jolting, it did not run many yards.  When it came to
rest I was about ten yards from the boundary.  Of course, I
stopped the engine before I commenced to descend.'[*]

[*] Aeronautical Journal, July, 1908. 

S. F. Cody, an American by birth, aroused the attention not only
of the British public, but of the War office and Admiralty as
well, as early as 1905 with his man-lifting kites.  In that year
a height of 1,600 feet was reached by one of these box-kites,
carrying a man, and later in the same year one Sapper Moreton,
of the Balloon Section of the Royal Engineers (the parent of the
Royal Flying Corps) remained for an hour at an altitude of 2,600
feet.  Following on the success of these kites, Cody constructed
an aeroplane which he designated a 'power kite,' which was in
reality a biplane that made the first flight in Great Britain. 
Speaking before the Aeronautical Society in 1908, Cody said that
'I have accomplished one thing that I hoped for very much, that
is, to be the first man to fly in Great Britain.... I made a
machine that left the ground the first time out; not high,
possibly five or six inches only.  I might have gone higher if I
wished.  I made some five flights in all, and the last flight
came to grief.... On the morning of the accident I went out
after adjusting my propellers at 8 feet pitch running at 600
(revolutions per minute).  I think that I flew at about
twenty-eight miles per hour.  I had 50 horsepower motor power in
the engine.  A bunch of trees, a flat common above these trees,
and from this flat there is a slope goes down... to another clump
of trees.  Now, these clumps of trees are a quarter of a mile
apart or thereabouts.... I was accused of doing nothing but
jumping with my machine, so I got a bit agitated and went to fly.

I went out this morning with an easterly wind, and left the
ground at the bottom of the hill and struck the ground at the
top, a distance of 74 yards.  That proved beyond a doubt that the
machine would fly--it flew uphill.  That was the most talented
flight the machine did, in my opinion.  Now, I turned round at
the top and started the machine and left the ground--remember, a
ten mile wind was blowing at the time.  Then, 60 yards from where
the men let go, the machine went off in this direction
(demonstrating)--I make a line now where I hoped to land--to cut
these trees off at that side and land right off in here.  I got
here somewhat excited, and started down and saw these trees right
in front of me.  I did not want to smash my head rudder to
pieces, so I raised it again and went up.  I got one wing direct
over that clump of trees, the right wing over the trees, the left
wing free; the wind, blowing with me, had to lift over these
trees.  So I consequently got a false lift on the right side and
no lift on the left side.  Being only about 8 feet from the tree
tops, that turned my machine up like that (demonstrating).  This
end struck the ground shortly after I had passed the trees.  I
pulled the steering handle over as far as I could.  Then I faced
another bunch of trees right in front of me.  Trying to avoid
this second bunch of trees I turned the rudder, and turned it
rather sharp.  That side of the machine struck, and it crumpled
up like so much tissue paper, and the machine spun round and
struck the ground that way on, and the framework was considerably
wrecked.  Now, I want to advise all aviators not to try to fly
with the wind and to cross over any big clump of earth or any
obstacle of any description unless they go square over the top of
it, because the lift is enormous crossing over anything like
that, and in coming the other way against the wind it would be
the same thing when you arrive at the windward side of the
obstacle.  That is a point I did not think of, and had I thought
of it I would have been more cautious.'

This Cody machine was a biplane with about 40 foot span, the
wings being about 7 feet in depth with about 8 feet between
upper and lower wing surfaces.  'Attached to the extremities of
the lower planes are two small horizontal planes or rudders,
while a third small vertical plane is fixed over the centre of
the upper plane.'  The tail-piece and principal rudder were
fitted behind the main body of the machine, and a horizontal
rudder plane was rigged out in front, on two supporting arms
extending from the centre of the machine.  The small end-planes
and the vertical plane were used in conjunction with the main
rudder when turning to right or left, the inner plane being
depressed on the turn, and the outer one correspondingly raised,
while the vertical plane, working in conjunction, assisted in
preserving stability.  Two two-bladed propellers were driven by
an eight-cylinder 50 horse-power Antoinette motor.  With this
machine Cody made his first flights over Laffan's plain, being
then definitely attached to the Balloon Section of the Royal
Engineers as military aviation specialist.

There were many months of experiment and trial, after the
accident which Cody detailed in the statement given above, and
then, on May 14th, 1909, Cody took the air and made a flight of
1,200 yards with entire success.  Meanwhile A. V. Roe was
experimenting at Lea Marshes with a triplane of rather curious
design the pilot having his seat between two sets of three
superposed planes, of which the front planes could be tilted and
twisted while the machine was in motion.  He comes but a little
way after Cody in the chronology of early British experimenters,
but Cody, a born inventor, must be regarded as the pioneer of
the present century so far as Britain is concerned.  He was
neither engineer nor trained mathematician, but he was a good
rule-of-thumb mechanic and a man of pluck and perseverance; he
never strove to fly on an imperfect machine, but made alteration
after alteration in order to find out what was improvement and
what was not, in consequence of which it was said of him that he
was 'always satisfied with his alterations.'

By July of 1909 he had fitted an 80 horse-power motor to his
biplane, and with this he made a flight of over four miles over
Laffan's Plain on July 21st.  By August he was carrying
passengers, the first being Colonel Capper of the R.E. Balloon
Section, who flew with Cody for over two miles, and on September
8th, 1909, he made a world's record cross-country flight of
over forty miles in sixty-six minutes, taking a course from
Laffan's Plain over Farnborough, Rushmoor, and Fleet, and back
to Laffan's Plain.  He was one of the competitors in the 1909
Doncaster Aviation Meeting, and in 1910 he competed at
Wolverhampton, Bournemouth, and Lanark.  It was on June 7th,
1910, that he qualified for his brevet, No. 9, on the Cody
biplane.

He built a machine which embodied all the improvements for which
he had gained experience, in 1911, a biplane with a length of
35 feet and span of 43 feet, known as the 'Cody cathedral' on
account of its rather cumbrous appearance.  With this, in 1911,
he won the two Michelin trophies presented in England, completed
the Daily Mail circuit of Britain, won the Michelin
cross-country prize in 1912 and altogether, by the end of 1912,
had covered more than 7,000 miles with the machine.  It was
fitted with a 120 horse-power Austro-Daimler engine, and was
characterised by an exceptionally wide range of speed--the great
wingspread gave a slow landing speed.

A few of his records may be given:  in 1910, flying at Laffan's
Plain in his biplane, fitted with a 50-60 horsepower Green
engine, on December 31st, he broke the records for distance and
time by flying 185 miles, 787 yards, in 4 hours 37 minutes.  On
October 31st, 1911, he beat this record by flying for 5 hours 15
minutes, in which period he covered 261 miles 810 yards with a 60
horse-power Green engine fitted to his biplane.  In 1912,
competing in the British War office tests of military
aeroplanes, he won the L5,000 offered by the War Office.  This
was in competition with no less than twenty-five other machines,
among which were the since-famous Deperdussin, Bristol,
Flanders, and Avro types, as well as the Maurice Farman and
Bleriot makes of machine.  Cody's remarkable speed range was
demonstrated in these trials, the speeds of his machine varying
between 72.4 and 48.5 miles per hour.  The machine was the only
one delivered for the trials by air, and during the three hours'
test imposed on all competitors a maximum height of 5,000 feet
was reached, the first thousand feet being achieved in three and
a half minutes.

During the summer of 1913 Cody put his energies into the
production of a large hydro-biplane, with which he intended to
win the L5,000 prize offered by the Daily Mail to the first
aviator to fly round Britain on a waterplane.  This machine was
fitted with landing gear for its tests, and, while flying it
over Laffan's Plain on August 7th, 1913, with Mr W. H. B. Evans
as passenger, Cody met with the accident that cost both
him and his passenger their lives.  Aviation lost a great figure
by his death, for his plodding, experimenting, and dogged
courage not only won him the fame that came to a few of the
pilots of those days, but also advanced the cause of flying very
considerably and contributed not a little to the sum of
knowledge in regard to design and construction.

Another figure of the early days was A. V. Roe, who came from
marine engineering to the motor industry and aviation in 1905. 
In 1906 he went out to Colorado, getting out drawings for the
Davidson helicopter, and in 1907 having returned to England, he
obtained highest award out of 200 entries in a model aeroplane
flying competition.  From the design of this model he built a
full-sized machine, and made a first flight on it, fitted with a
24 horse-power Antoinette engine, in June of 1908 Later, he
fitted a 9 horsepower motor-cycle engine to a triplane of his
own design, and with this made a number of short flights; he got
his flying brevet on a triplane with a motor of 35 horse-power,
which, together with a second triplane, was entered for the
Blackpool aviation meeting of 1910 but was burnt in transport to
the meeting.  He was responsible for the building of the first
seaplane to rise from English waters, and may be counted the
pioneer of the tractor type of biplane.  In 1913 he built a
two-seater tractor biplane with 80 horse-power engine, a machine
which for some considerable time ranked as a leader of design. 
Together with E. V. Roe and H. V. Roe, 'A. V.' controlled the
Avro works, which produced some of the most famous training
machines of the war period in a modification of the original 80
horse-power tractor.  The first of the series of Avro tractors
to be adopted by the military authorities was the 1912 biplane, a
two-seater fitted with 50 horsepower engine.  It was the first
tractor biplane with a closed fuselage to be used for military
work, and became standard for the type.  The Avro seaplane, of I 
100 horse-power (a fourteen-cylinder Gnome engine was used) was
taken up by the British Admiralty in 1913.  It had a length of 34
feet and a wing-span of 50 feet, and was of the twin-float type.

Geoffrey de Havilland, though of later rank, counts high among
designers of British machines.  He qualified for his brevet as
late as February, 1911, on a biplane of his own construction, and
became responsible for the design of the BE2, the first
successful British Government biplane.  On this he made a British
height record of 10,500 feet over Salisbury Plain, in August of
1912, when he took up Major Sykes as passenger.  In the war
period he was one of the principal designers of fighting and
reconnaissance machines. 

F. Handley Page, who started in business as an aeroplane
builder in 1908, having works at Barking, was one of the
principal exponents of the inherently stable machine, to which
he devoted practically all his experimental work up to the
outbreak of war.  The experiments were made with various
machines, both of monoplane and biplane type, and of these one
of the best was a two-seater monoplane built in 1911, while a
second was a larger machine, a biplane, built in 1913 and fitted
with a 110 horse-power Anzani engine.  The war period brought out
the giant biplane with which the name of Handley Page is most
associated, the twin-engined night-bomber being a familiar
feature of the later days of the war; the four-engined bomber had
hardly had a chance of proving itself under service conditions
when the war came to an end.

Another notable figure of the early period was 'Tommy' Sopwith,
who took his flying brevet at Brooklands in November of 1910,
and within four days made the British duration record of 108
miles in 3 hours 12 minutes.  On December 18th, 1910, he won the
Baron de Forrest prize of L4,000 for the longest flight from
England to the Continent, flying from Eastchurch to Tirlemont,
Belgium, in three hours, a distance of 161 miles.  After two
years of touring in America, he returned to England and
established a flying school.  In 1912 he won the first aerial
Derby, and in 1913 a machine of his design, a tractor biplane,
raised the British height record to 13,000 feet (June 16th, at
Brooklands).  First as aviator, and then as designer, Sopwith has
done much useful work in aviation.

These are but a few, out of a host who contributed to the
development of flying in this country, for, although France may
be said to have set the pace as regards development, Britain was
not far behind.  French experimenters received far more
Government aid than did the early British aviators and
designers--in the early days the two were practically
synonymous, and there are many stories of the very early days at
Brooklands, where, when funds ran low, the ardent spirits
patched their trousers with aeroplane fabric and went on with
their work with Bohemian cheeriness.  Cody, altering and
experimenting on Laffan's Plain, is the greatest figure of them
all, but others rank, too, as giants of the early days, before
the war brought full recognition of the aeroplane's
potentialities.

one of the first men actually to fly in England, Mr J. C. T. 
Moore-Brabazon, was a famous figure in the days of exhibition
flying, and won his reputation mainly through being first to fly
a circular mile on a machine designed and built in Great Britain
and piloted by a British subject.  Moore-Brabazon's earliest
flights were made in France on a Voisin biplane in 1908, and he
brought this machine over to England, to the Aero Club grounds
at Shellness, but soon decided that he would pilot a British
machine instead.  An order was placed for a Short machine, and
this, fitted with a 50-60 horse-power Green engine, was used for
the circular mile, which won a prize of L1,000 offered by the
Daily Mail, the feat being accomplished on October 30th, 1909.
Five days later, Moore-Brabazon achieved the longest flight up
to that time accomplished on a British-built machine, covering
three and a half miles.  In connection with early flying in
England, it is claimed that A. V. Roe, flying 'Avro B,',' on
June 8th, 1908, was actually the first man to leave the ground,
this being at Brooklands, but in point of fact Cody antedated
him.

No record of early British fliers could be made without the name
of C. S. Rolls, a son of Lord Llangattock, on June 2nd, 1910,
he flew across the English Channel to France, until he was duly
observed over French territory, when he returned to England
without alighting.  The trip was made on a Wright biplane, and
was the third Channel crossing by air, Bleriot having made the
first, and Jacques de Lesseps the second.  Rolls was first to
make the return journey in one trip.  He was eventually killed
through the breaking of the tail-plane of his machine in
descending at a flying meeting at Bournemouth.  The machine was
a Wright biplane, but the design of the tail-plane--which, by
the way, was an addition to the machine, and was not even
sanctioned by the Wrights--appears to have been carelessly
executed, and the plane itself was faulty in construction.  The
breakage caused the machine to overturn, killing Rolls, who was
piloting it.



XIV. RHEIMS, AND AFTER

The foregoing brief--and necessarily incomplete--survey of the
early British group of fliers has taken us far beyond some of
the great events of the early days of successful flight, and it
is necessary to go back to certain landmarks in the history of
aviation, first of which is the great meeting at Rheims in 1909. 
Wilbur Wright had come to Europe, and, flying at Le Mans and
Pau--it was on August 8th, 1908, that Wilbur Wright made the
first of his ascents in Europe--had stimulated public interest
in flying in France to a very great degree.  Meanwhile, Orville
Wright, flying at Fort Meyer, U.S.A., with Lieutenant Selfridge
as a passenger, sustained an accident which very nearly cost him
his life through the transmission gear of the motor breaking. 
Selfridge was killed and Orville Wright was severely injured--it
was the first fatal accident with a Wright machine.

Orville Wright made a flight of over an hour on September 9th,
1908, and on December 31st of that year Wilbur flew for 2 hours
19 minutes.  Thus, when the Rheims meeting was organised--more
notable because it was the first of its kind, there were already
records waiting to be broken.  The great week opened on August
22nd, there being thirty entrants, including all the most famous
men among the early fliers in France.  Bleriot, fresh from his
Channel conquest, was there, together with Henry Farman,
Paulhan, Curtiss, Latham, and the Comte de Lambert, first pupil
of the Wright machine in Europe to achieve a reputation as an
aviator.

'To say that this week marks an epoch in the history of the
world is to state a platitude.  Nevertheless, it is worth
stating, and for us who are lucky enough to be at Rheims during
this week there is a solid satisfaction in the idea that we are
present at the making of history.  In perhaps only a few years
to come the competitions of this week may look pathetically
small and the distances and speeds may appear paltry. 
Nevertheless, they are the first of their kind, and that is
sufficient.'

So wrote a newspaper correspondent who was present at the famous
meeting, and his words may stand, being more than mere
journalism; for the great flying week which opened on August
22nd, 1909, ranks as one of the great landmarks in the history
of heavier-than-air flight.  The day before the opening of the
meeting a downpour of rain spoilt the flying ground; Sunday
opened with a fairly high wind, and in a lull M. Guffroy turned
out on a crimson R.E.P. monoplane, but the wheels of his
undercarriage stuck in the mud and prevented him from rising in
the quarter of an hour allowed to competitors to get off the
ground.  Bleriot, following, succeeded in covering one side of
the triangular course, but then came down through grit in the
carburettor.  Latham, following him with thirteen as the number
of his machine, experienced his usual bad luck and came to earth
through engine trouble after a very short flight.  Captain
Ferber, who, owing to military regulations, always flew under
the name of De Rue, came out next with his Voisin biplane, but
failed to get off the ground; he was followed by Lefebvre on a
Wright biplane, who achieved the success of the morning by
rounding the course--a distance of six and a quarter miles--in
nine minutes with a twenty mile an hour wind blowing.  His
flight finished the morning.

Wind and rain kept competitors out of the air until the evening,
when Latham went up, to be followed almost immediately by the
Comte de Lambert.  Sommer, Cockburn (the only English
competitor), Delagrange, Fournier, Lefebvre, Bleriot,
Bunau-Varilla, Tissandier, Paulhan, and Ferber turned out after
the first two, and the excitement of the spectators at seeing so
many machines in the air at one time provoked wild cheering. 
The only accident of the day came when Bleriot damaged his
propeller in colliding with a haycock.

The main results of the day were that the Comte de Lambert flew
30 kilometres in 29 minutes 2 seconds; Lefebvre made the
ten-kilometre circle of the track in just a second under 9
minutes, while Tissandier did it in 9 1/4 minutes, and Paulhan
reached a height of 230 feet.  Small as these results seem to us
now, and ridiculous as may seem enthusiasm at the sight of a few
machines in the air at the same time, the Rheims Meeting remains
a great event, since it proved definitely to the whole world
that the conquest of the air had been achieved.

Throughout the week record after record was made and broken. 
Thus on the Monday, Lefebvre put up a record for rounding the
course and Bleriot beat it, to be beaten in turn by Glenn
Curtiss on his Curtiss-Herring biplane.  On that day, too,
Paulhan covered 34 3/4 miles in 1 hour 6 minutes.  On the next
day, Paulhan on his Voisin biplane took the air with Latham, and
Fournier followed, only to smash up his machine by striking an
eddy of wind which turned him over several times.  On the
Thursday, one of the chief events was Latham's 43 miles
accomplished in 1 hour 2 minutes in the morning and his 96.5
miles in 2 hours 13 minutes in the afternoon, the latter flight
only terminated by running out of petrol.  On the Friday, the
Colonel Renard French airship, which had flown over the ground
under the pilotage of M. Kapfarer, paid Rheims a second visit;
Latham manoeuvred round the airship on his Antoinette and finally
left it far behind.  Henry Farman won the Grand Prix de Champagne
on this day, covering 112 miles in 3 hours, 4 minutes, 56
seconds, Latham being second with his 96.5 miles flight, and
Paulhan third.

On the Saturday, Glenn Curtiss came to his own, winning the
Gordon-Bennett Cup by covering 20 kilometres in 15 minutes
50.6 seconds.  Bleriot made a good second with 15 minutes 56.2
seconds as his time, and Latham and Lefebvre were third and
fourth.  Farman carried off the passenger prize by carrying two
passengers a distance of 6 miles in 10 minutes 39 seconds.  On
the last day Delagrange narrowly escaped serious accident
through the bursting of his propeller while in the air, Curtiss
made a new speed record by travelling at the rate of over 50
miles an hour, and Latham, rising to 500 feet, won the altitude
prize.

These are the cold statistics of the meeting; at this length of
time it is difficult to convey any idea of the enthusiasm of the
crowds over the achievements of the various competitors, while
the incidents of the week, comic and otherwise, are nearly
forgotten now even by those present in this making of history. 
Latham's great flight on the Thursday was rendered a breathless
episode by a downpour of rain when he had covered all but a
kilometre of the record distance previously achieved by Paulhan,
and there was wild enthusiasm when Latham flew on through the
rain until he had put up a new record and his petrol had run
out.  Again, on the Friday afternoon, the Colonel Renard took
the air together with a little French dirigible, Zodiac III;
Latham was already in the air directly over Farman, who was also
flying, and three crows which turned out as rivals to the human
aviators received as much cheering for their appearance as had
been accorded to the machines, which doubtless they could not
understand.  Frightened by the cheering, the crows tried to
escape from the course, but as they came near the stands, the
crowd rose to cheer again and the crows wheeled away to make a
second charge towards safety, with the same result; the crowd
rose and cheered at them a third and fourth time; between ten
and fifteen thousand people stood on chairs and tables and waved
hats and handkerchiefs at three ordinary, everyday crows.  One
thoughtful spectator, having thoroughly enjoyed the funny side
of the incident, remarked that the ultimate mastery of the air
lies with the machine that comes nearest to natural flight. 
This still remains for the future to settle.

Farman's world record, which won the Grand Prix de Champagne,
was done with a Gnome Rotary Motor which had only been run on
the test bench and was fitted to his machine four hours before
he started on the great flight.  His propeller had never been
tested, having only been completed the night before.  The
closing laps of that flight, extending as they did into the
growing of the dusk, made a breathlessly eerie experience for
such of the spectators as stayed on to watch--and these were
many.  Night came on steadily and Farman covered lap after lap
just as steadily, a buzzing, circling mechanism with something
relentless in its isolated persistency.

The final day of the meeting provided a further record in the
quarter million spectators who turned up to witness the close of
the great week.  Bleriot, turning out in the morning, made a
landing in some such fashion as flooded the carburettor and
caused it to catch fire.  Bleriot himself was badly burned,
since the petrol tank burst and, in the end, only the metal
parts of the machine were left.  Glenn Curtis tried to beat
Bleriot's time for a lap of the course, but failed.  In the
evening, Farman and Latham went out and up in great circles,
Farman cleaving his way upward in what at the time counted for a
huge machine, on circles of about a mile diameter.  His first
round took him level with the top of the stands, and, in his
second, he circled the captive balloon anchored in the middle of
the grounds. After another circle, he came down on a long glide,
when Latham's lean Antoinette monoplane went up in circles more
graceful than those of Farman.  'Swiftly it rose and swept round
close to the balloon, veered round to the hangars, and out over
to the Rheims road.  Back it came high over the stands, the
people craning their necks as the shrill cry of the engine drew
nearer and nearer behind the stands.  Then of a sudden, the
little form appeared away up in the deep twilight blue vault of
the sky, heading straight as an arrow for the anchored balloon. 
Over it, and high, high above it went the Antoinette, seemingly
higher by many feet than the Farman machine.  Then, wheeling in
a long sweep to the left, Latham steered his machine round past
the stands, where the people, their nerve-tension released on
seeing the machine descending from its perilous height of 500
feet, shouted their frenzied acclamations to the hero of the
meeting.

'For certainly "Le Tham," as the French call him, was the
popular hero.  He always flew high, he always flew well, and his
machine was a joy to the eye, either afar off or at close
quarters.  The public feeling for Bleriot is different. 
Bleriot, in the popular estimation, is the man who fights
against odds, who meets the adverse fates calmly and with good
courage, and to whom good luck comes once in a while as a reward
for much labour and anguish, bodily and mental.  Latham is the
darling of the Gods, to whom Fate has only been unkind in the
matter of the Channel flight, and only then because the honour
belonged to Bleriot.

'Next to these two, the public loved most Lefebvre, the joyous,
the gymnastic.  Lefebvre was the comedian of the meeting.  When
things began to flag, the gay little Lefebvre would trot out to
his starting rail, out at the back of the judge's enclosure
opposite the stands, and after a little twisting of propellers
his Wright machine would bounce off the end of its starting rail
and proceed to do the most marvellous tricks for the benefit of
the crowd, wheeling to right and left, darting up and down, now
flying over a troop of the cavalry who kept the plain clear of
people and sending their horses into hysterics, anon making
straight for an unfortunate photographer who would throw himself
and his precious camera flat on the ground to escape
annihilation as Lefebvre swept over him 6 or 7 feet off the
ground.  Lefebvre was great fun, and when he had once found that
his machine was not fast enough to compete for speed with the
Bleriots, Antoinettes, and Curtiss, he kept to his metier of
amusing people.  The promoters of the meeting owe Lefebvre a
debt of gratitude, for he provided just the necessary comic
relief.'--(The Aero, September 7th, 1909.)

It may be noted, in connection with the fact that Cockburn was
the only English competitor at the meeting, that the Rheims
Meeting did more than anything which had preceded it to waken
British interest in aviation.  Previously, heavier-than-air
flight in England had been regarded as a freak business by the
great majority, and the very few pioneers who persevered toward
winning England a share in the conquest of the air came in for
as much derision as acclamation.  Rheims altered this; it taught
the world in general, and England in particular, that a serious
rival to the dirigible balloon had come to being, and it
awakened the thinking portion of the British public to the fact
that the aeroplane had a future.

The success of this great meeting brought about a host of
imitations of which only a few deserve bare mention since,
unlike the first, they taught nothing and achieved little. 
There was the meeting at Boulogne late in September of 1909, of
which the only noteworthy event was Ferber's death.  There was a
meeting at Brescia where Curtiss again took first prize for
speed and Rougier put up a world's height record of 645 feet. 
The Blackpool meeting followed between 18th and 23rd of
October, 1909, forming, with the exception of Doncaster, the
first British Flying Meeting.  Chief among the competitors were
Henry Farman, who took the distance prize, Rougier, Paulhan, and
Latham, who, by a flight in a high wind, convinced the British
public that the theory that flying was only possible in a calm
was a fallacy.  A meeting at Doncaster was practically
simultaneous with the Blackpool week; Delagrange, Le Blon,
Sommer, and Cody were the principal figures in this event.  It
should be added that 130 miles was recorded as the total flown
at Doncaster, while at Blackpool only 115 miles were flown. 
Then there were Juvisy, the first Parisian meeting,
Wolverhampton, and the Comte de Lambert's flight round the
Eiffel Tower at a height estimated at between 1,200 and 1,300
feet.  This may be included in the record of these aerial
theatricals, since it was nothing more.

Probably wakened to realisation of the possibilities of the
aeroplane by the Rheims Meeting, Germany turned out its first
plane late in 1909.  It was known as the Grade monoplane, and
was a blend of the Bleriot and Santos-Dumont machines, with a
tail suggestive of the Antoinette type.  The main frame took the
form of a single steel tube, at the forward end of which was
rigged a triangular arrangement carrying the pilot's seat and
the landing wheels underneath, with the wing warping wires and
stays above.  The sweep of the wings was rather similar to the
later Taube design, though the sweep back was not so pronounced,
and the machine was driven by a four-cylinder, 20 horse-power,
air-cooled engine which drove a two-bladed tractor propeller. 
In spite of Lilienthal's pioneer work years before, this was the
first power-driven German plane which actually flew.

Eleven months after the Rheims meeting came what may be reckoned
the only really notable aviation meeting on English soil, in the
form of the Bournemouth week, July 10th to 16th, 1910.  This
gathering is noteworthy mainly in view of the amazing advance
which it registered on the Rheims performances.  Thus, in the
matter of altitude, Morane reached 4,107 feet and Drexel came
second with 2,490 feet.  Audemars on a Demoiselle monoplane made
a flight of 17 miles 1,480 yards in 27 minutes 17.2 seconds, a
great flight for the little Demoiselle.  Morane achieved a speed
of 56.64 miles per hour, and Grahame White climbed to 1,000 feet
altitude in 6 minutes 36.8 seconds.  Machines carrying the Gnome
engine as power unit took the great bulk of the prizes, and
British-built engines were far behind.

The Bournemouth Meeting will always be remembered with regret
for the tragedy of C. S. Rolls's death, which took place on
the Tuesday, the second day of the meeting.  The first
competition of the day was that for the landing prize; Grahame
White, Audemars, and Captain Dickson had landed with varying
luck, and Rolls, following on a Wright machine with a tail-plane
which ought never to have been fitted and was not part of the
Wright design, came down wind after a left-hand turn and turned
left again over the top of the stands in order to land up wind. 
He began to dive when just clear of the stands, and had dropped
to a height of 40 feet when he came over the heads of the people
against the barriers.  Finding his descent too steep, he pulled
back his elevator lever to bring the nose of the machine up,
tipping down the front end of the tail to present an almost flat
surface to the wind.  Had all gone well, the nose of the machine
would have been forced up, but the strain on the tail and its
four light supports was too great; the tail collapsed, the wind
pressed down the biplane elevator, and the machine dived
vertically for the remaining 20 feet of the descent, hitting the
ground vertically and crumpling up.  Major Kennedy, first to
reach the debris, found Rolls lying with his head doubled under
him on the overturned upper main plane; the lower plane had been
flung some few feet away with the engine and tanks under it. 
Rolls was instantaneously killed by concussion of the brain.

Antithesis to the tragedy was Audemars on his Demoiselle, which
was named 'The Infuriated Grasshopper.'  Concerning this, it was
recorded at the time that 'Nothing so excruciatingly funny as
the action of this machine has ever been seen at any aviation
ground.  The little two-cylinder engine pops away with a sound
like the frantic drawing of ginger beer corks; the machine
scutters along the ground with its tail well up; then down comes
the tail suddenly and seems to slap the ground while the front
jumps up, and all the spectators rock with laughter.  The whole
attitude and the jerky action of the machine suggest a
grasshopper in a furious rage, and the impression is intensified
when it comes down, as it did twice on Wednesday, in long grass,
burying its head in the ground in its temper.'--(The Aero, July,
1910.)

The Lanark Meeting followed in August of the same year, and with
the bare mention of this, the subject of flying meetings may he
left alone, since they became mere matters of show until there
came military competitions such as the Berlin Meeting at the end
of August, 1910, and the British War office Trials on Salisbury
Plain, when Cody won his greatest triumphs.  The Berlin meeting
proved that, from the time of the construction of the first
successful German machine mentioned above, to the date of the
meeting, a good number of German aviators had qualified for
flight, but principally on Wright and Antoinette machines, though
by that time the Aviatik and Dorner German makes had taken the
air.  The British War office Trials deserve separate and longer
mention.

In 1910 in spite of official discouragement, Captain Dickson
proved the value of the aeroplane for scouting purposes by
observing movements of troops during the Military Manoeuvres on
Salisbury Plain.  Lieut. Lancelot Gibbs and Robert Loraine,
the actor-aviator, also made flights over the manoeuvre area,
locating troops and in a way anticipating the formation and work
of the Royal Flying Corps by a usefulness which could not be
officially recognised.



XV. THE CHANNEL CROSSING

It may be said that Louis Bleriot was responsible for the second
great landmark in the history of successful flight.  The day when
the brothers Wright succeeded in accomplishing power-driven
flight ranks as the first of these landmarks.  Ader may or may
not have left the ground, but the wreckage of his 'Avion' at the
end of his experiment places his doubtful success in a different
category from that of the brothers Wright and leaves them the
first definite conquerors, just as Bleriot ranks as first
definite conqueror of the English Channel by air.

In a way, Louis Bleriot ranks before Farman in point of time;
his first flapping-wing model was built as early as 1900, and
Voisin flew a biplane glider of his on the Seine in the very
early experimental days.  Bleriot's first four machines were
biplanes, and his fifth, a monoplane, was wrecked almost
immediately after its construction. Bleriot had studied
Langley's work to a certain extent, and his sixth construction
was a double monoplane based on the Langley principle.  A month
after he had wrecked this without damaging himself-- for Bleriot
had as many miraculous escapes as any of the other fliers-he
brought out number seven, a fairly average monoplane.  It was in
December of 1907 after a series of flights that he wrecked this
machine, and on its successor, in July of 1908, he made a
flight of over 8 minutes.  Sundry flights, more or less
successful, including the first cross-country flight from Toury
to Artenay, kept him busy up to the beginning of November, 1908,
when the wreckage in a fog of the machine he was flying sent him
to the building of 'number eleven,' the famous cross-channel
aeroplane.

Number eleven was shown at the French Aero Show in the Grand
Palais and was given its first trials on the 18th January, 1909. 
It was first fitted with a R.E.P. motor and had a lifting area
of 120 square feet, which was later increased to 150 square
feet.  The framework was of oak and poplar spliced and
reinforced with piano wire; the weight of the machine was 47
lbs. and the undercarriage weight a further 60 lbs., this
consisting of rubber cord shock absorbers mounted on two wheels. 
The R.E.P. motor was found unsatisfactory, and a three-cylinder
Anzani of 105 mm. bore and 120 mm. stroke replaced it.  An
accident seriously damaged the machine on June 2nd, but Bleriot
repaired it and tested it at Issy, where between June 19th and
June 23rd he accomplished flights of 8, 12, 15, 16, and 36
minutes.  On July 4th he made a 50-minute flight and on the 13th
flew from Etampes to Chevilly.

A few further details of construction may be given:  the wings
themselves and an elevator at the tail controlled the rate of
ascent and descent, while a rudder was also fitted at the tail. 
The steering lever, working on a universally jointed
shaft--forerunner of the modern joystick--controlled both the
rudder and the wings, while a pedal actuated the elevator.  The
engine drove a two-bladed tractor screw of 6 feet 7 inches
diameter, and the angle of incidence of the wings was 20
degrees.  Timed at Issy, the speed of the machine was given as 36
miles an hour, and as Bleriot accomplished the Channel flight of
20 miles in 37 minutes, he probably had a slight following wind.

The Daily Mail had offered a prize of L1,000 for the first
Cross-Channel flight, and Hubert Latham set his mind on winning
it.  He put up a shelter on the French coast at Sangatte,
half-way between Calais and Cape Blanc Nez.  From here he made
his first attempt to fly to England on Monday the 19th of July. 
He soared to a fair height, circling, and reached an estimated
height of about 900 feet as he came over the water with every
appearance of capturing the Cross-Channel prize.  The luck which
dogged his career throughout was against him, for, after he had
covered some 8 miles, his engine stopped and he came down to the
water in a series of long glides.  It was discovered afterward
that a small piece of wire had worked its way into a vital part
of the engine to rob Latham of the honour he coveted.  The tug
that came to his rescue found him seated on the fuselage of his
Antoinette, smoking a cigarette and waiting for a boat to take
him to the tug.  It may be remarked that Latham merely assumed
his Antoinette would float in case he failed to make the English
coast; he had no actual proof.

Bleriot immediately entered his machine for the prize and took
up his quarters at Barraques.  On Sunday, July 25th, 1909,
shortly after 4 a.m., Bleriot had his machine taken out from its
shelter and prepared for flight.  He had been recently injured
in a petrol explosion and hobbled out on crutches to make his
cross-Channel attempt; he made two great circles in the air to
try the machine, and then alighted.  'In ten  minutes I start
for England,' he declared, and at 4.35 the motor was started up. 
After a run of 100 yards, the machine rose in the air and got a
height of about 100 feet over the land, then wheeling sharply
seaward and heading for Dover.

Bleriot had no means of telling direction, and any change of
wind might have driven him out over the North Sea, to be lost,
as were Cecil Grace and Hamel later on.  Luck was with him,
however, and at 5.12 a.m. of that July Sunday, he made his
landing in the North Fall meadow, just behind Dover Castle. 
Twenty minutes out from the French coast, he lost sight of the
destroyer which was patrolling the Channel, and at the same time
he was out of sight of land without compass or any other means
of ascertaining his direction.  Sighting the English coast, he
found that he had gone too far to the east, for the wind
increased in strength throughout the flight, this to such an
extent as almost to turn the machine round when he came over
English soil.  Profiting by Latham's experience, Bleriot had
fitted an inflated rubber cylinder a foot in diameter by 5 feet
in length along the middle of his fuselage, to render floating a
certainty in case he had to alight on the water.

Latham in his camp at Sangatte had been allowed to sleep through
the calm of the early morning through a mistake on the part of a
friend, and when his machine was turned out--in order that he
might emulate Bleriot, although he no longer hoped to make the
first flight, it took so long to get the machine ready and
dragged up to its starting-point that there was a 25 mile an
hour wind by the time everything was in readiness.  Latham was
anxious to make the start in spite of the wind, but the
Directors of the Antoinette Company refused permission.  It was
not until two days later that the weather again became
favourable, and then with a fresh machine, since the one on
which he made his first attempt had been very badly damaged in
being towed ashore, he made a circular trial flight of about 5
miles.  In landing from this, a side gust of wind drove the nose
of the machine against a small hillock, damaging both propeller
blades and chassis, and it was not until evening that the damage
was repaired.

French torpedo boats were set to mark the route, and Latham set
out on his second attempt at six o'clock.  Flying at a height of
200 feet, he headed over the torpedo boats for Dover and seemed
certain of making the English coast, but a mile and a half out
from Dover his engine failed him again, and he dropped to the
water to be picked up by the steam pinnace of an English warship
and put aboard the French destroyer Escopette.

There is little to choose between the two aviators for courage
in attempting what would have been considered a foolhardy feat a
year or two before.  Bleriot's state, with an abscess in the
burnt foot which had to control the elevator of his machine,
renders his success all the more remarkable.  His machine was
exhibited in London for a time, and was afterwards placed in the
Conservatoire des Arts et Metiers, while a memorial in stone,
copying his monoplane in form, was let into the turf at the
point where he landed.

The second Channel crossing was not made until 1910, a year of
new records.  The altitude record had been lifted to over 10,000
feet, the duration record to 8 hours 12 minutes, and the
distance for a single flight to 365 miles, while a speed of over
65 miles an hour had been achieved, when Jacques de Lesseps, son
of the famous engineer of Suez Canal and Panama fame, crossed
from France to England on a Bleriot monoplane. By this time
flying had dropped so far from the marvellous that this second
conquest of the Channel aroused but slight public interest in
comparison with Bleriot's feat.

The total weight of Bleriot's machine in Cross Channel trim was
660 lbs., including the pilot and sufficient petrol for a three
hours' run; at a speed of 37 miles an hour, it was capable of
carrying about 5 lbs. per square foot of lifting surface.  It
was the three-cylinder 25 horse-power Anzani motor which drove
the machine for the flight.  Shortly after the flight had been
accomplished, it was announced that the Bleriot firm would
construct similar machines for sale at L400 apiece--a good
commentary on the prices of those days.

On June the 2nd, 1910, the third Channel crossing was made by C.
S. Rolls, who flew from Dover, got himself officially observed
over French soil at Barraques, and then flew back without
landing.  He was the first to cross from the British side of the
Channel and also was the first aviator who made the double
journey.  By that time, however, distance flights had so far
increased as to reduce the value of the feat, and thenceforth
the Channel crossing was no exceptional matter.  The honour,
second only to that of the Wright Brothers, remains with Bleriot.



XVI. LONDON TO MANCHESTER

The last of the great contests to arouse public enthusiasm was
the London to Manchester Flight of 1910.  As far back as 1906,
the Daily Mail had offered a prize of L10,000 to the first
aviator who should accomplish this journey, and, for a long time,
the offer was regarded as a perfectly safe one for any person or
paper to make--it brought forth far more ridicule than belief. 
Punch offered a similar sum to the first man who should swim the
Atlantic and also for the first flight to Mars and back within a
week, but in the spring of 1910 Claude Grahame White and Paulhan,
the famous French pilot, entered  for the 183 mile run on which
the prize depended.  Both these competitors flew the Farman
biplane with the 50 horse-power Gnome motor as propulsive power.
Grahame White surveyed the ground along the route, and the L. &
N. W. Railway Company, at his request, whitewashed the sleepers
for 100 yards on the north side of all junctions to give him his
direction on the course. The machine was run out on to the
starting ground at Park Royal and set going at 5.19 a.m. on April
23rd.  After a run of 100 yards, the machine went up over
Wormwood Scrubs on its journey to Normandy, near Hillmorten,
which was the first arranged stopping place en route; Grahame
White landed here in good trim at 7.20 a.m., having covered 75
miles and made a world's record cross country flight.  At 8.15 he
set off again to come down at Whittington, four miles short of
Lichfield, at about 9.20, with his machine in good order except
for a cracked landing skid.  Twice, on this second stage of the
journey, he had been caught by gusts of wind which turned the
machine fully round toward London, and, when over a wood near
Tamworth, the engine stopped through a defect in the balance
springs of two exhaust valves; although it started up again
after a 100 foot glide, it did not give enough power to give him
safety in the gale he was facing.  The rising wind kept him on
the ground throughout the day, and, though he hoped for better
weather, the gale kept up until the Sunday evening.  The men in
charge of the machine during its halt had attempted to hold the
machine down instead of anchoring it with stakes and ropes, and,
in consequence of this, the wind blew the machine over on its
back, breaking the upper planes and the tail.  Grahame White had
to return to London, while the damaged machine was prepared for
a second flight.  The conditions of the competition enacted that
the full journey should be completed within 24 hours, which made
return to the starting ground inevitable.

Louis Paulhan, who had just arrived with his Farman machine,
immediately got it unpacked and put together in order to be
ready to make his attempt for the prize as soon as the weather
conditions should admit.  At 5.31 p.m., on April 27th, he went
up from Hendon and had travelled 50 miles when Grahame White,
informed of his rival's start, set out to overtake him.  Before
nightfall Paulhan landed at Lichfield, 117 miles from London,
while Grahame White had to come down at Roden, only 60 miles out.
The English aviator's chance was not so small as it seemed, for,
as Latham had found in his cross-Channel attempts, engine failure
was more the rule than the exception, and a very little thing
might reverse the relative positions.

A special train accompanied Paulhan along the North-Western
route, conveying Madame Paulhan, Henry Farman, and the mechanics
who fitted the Farman biplane together.  Paulhan himself, who
had flown at a height of 1,000 feet, spent the night at
Lichfield, starting again at 4.9 a.m.  On the 28th, passing
Stafford at 4.45, Crewe at 5.20, and landing at Burnage, near
Didsbury, at 5.32, having had a clean run.

Meanwhile, Grahame White had made a most heroic attempt to beat
his rival.  An hour before dawn on the 28th, he went to the
small field in which his machine had landed, and in the darkness
managed to make an ascent from ground which made starting
difficult even in daylight.  Purely by instinct and his
recollection of the aspect of things the night before, he had to
clear telegraph wires and a railway bridge, neither of which he
could possibly see at that hour.  His engine, too, was
faltering, and it was obvious to those who witnessed his start
that its note was far from perfect.

At 3.50 he was over Nuneaton and making good progress; between
Atherstone and Lichfield the wind caught him and the engine
failed more and more, until at 4.13 in the morning he was forced
to come to earth, having covered 6 miles less distance than in
his first attempt.  It was purely a case of engine failure, for,
with full power, he would have passed over Paulhan just as the
latter was preparing for the restart.  Taking into consideration
the two machines, there is little doubt that Grahame White
showed the greater flying skill, although he lost the prize. 
After landing and hearing of Paulhan's victory, on which he
wired congratulations, he made up his mind to fly to Manchester
within the 24 hours.  He started at 5 o'clock in the afternoon
from Polesworth, his landing place, but was forced to land at
5.30 at Whittington, where he had landed on the previous
Saturday.  The wind, which had forced his descent, fell again
and permitted of starting once more; on this third stage he
reached Lichfield, only to make his final landing at 7.15 p.m.,
near the Trent Valley station.  The defective running of the
Gnome engine prevented his completing the course, and his Farman
machine had to be brought back to London by rail.

The presentation of the prize to Paulhan was made the occasion
for the announcement of a further competition, consisting of a
1,000 mile flight round a part of Great Britain.  In this,
nineteen competitors started, and only four finished; the end of
the race was a great fight between Beaumont and Vedrines, both
of whom scorned weather conditions in their determination to
win.  Beaumont made the distance in a flying time of 22 hours 28
minutes 19 seconds, and Vedrines covered the journey in a little
over 23 1/2 hours.  Valentine came third on a Deperdussin
monoplane and S. F. Cody on his Cathedral biplane was fourth. 
This was in 1911, and by that time heavier-than-air flight had
so far advanced that some pilots had had war experience in the
Italian campaign in Tripoli, while long cross-country flights
were an everyday event, and bad weather no longer counted.



XVII. A SUMMARY, TO 1911

There is so much overlapping in the crowded story of the first
years of successful power-driven flight that at this point it is
advisable to make a concise chronological survey of the chief
events of the period of early development, although much of this
is of necessity recapitulation.  The story begins, of course,
with Orville Wright's first flight of 852 feet at Kitty Hawk on
December 19th, 1903.  The next event of note was Wright's flight
of 11.12 miles in 18 minutes 9 seconds at Dayton, Ohio, on
September 26th, 1905, this being the first officially recorded
flight.  On October 4th of the same year, Wright flew 20.75 miles
in 33 minutes 17 seconds, this being the first flight of over 20
miles ever made.  Then on September 14th 1906, Alberto
Santos-Dumont made a flight of eight seconds on the second
heavier-than-air machine he had constructed.  It was a big
box-kite-like machine; this was the second power-driven aeroplane
in Europe to fly, for although Santos-Dumont's first machine
produced in 1905 was reckoned an unsuccessful design, it had
actually got off the ground for brief periods.  Louis Bleriot
came into the ring on April 5th, 1907, with a first flight of 6
seconds on a Bleriot monoplane, his eighth but first successful
construction.

Henry Farman made his first appearance in the history of aviation
with a flight of 935 feet on a Voisin biplane on October 15th
1907.  On October 25th, in a flight of 2,530 feet, he made the
first recorded turn in the air, and on March 29th, 1908, carrying
Leon Delagrange on a Voisin biplane, he made the first passenger
flight.  On April 10th of this year, Delagrange, in flying 1 1/2
miles, made the first flight in Europe exceeding a mile in
distance.  He improved on this by flying 10 1/2 miles at Milan on
June 22nd, while on July 8th, at Turin, he took up Madame
Peltier, the first woman to make an aeroplane flight.

Wilbur Wright, coming over to Europe, made his first appearance
on the Continent with a flight of 1 3/4 minutes at Hunaudieres,
France, on August 8th, 1908.  On September 6th, at Chalons, he
flew for 1 hour 4 minutes 26 seconds with a passenger, this
being the first flight in which an hour in the air was exceeded
with a passenger on board.

on September 12th 1908, Orville Wright, flying at Fort Meyer,
U.S.A., with Lieut. Selfridge as passenger, crashed his
machine, suffering severe injuries, while Selfridge was killed. 
This was the first aeroplane fatality.  On October 30th, 1908,
Farman made the first cross-country flight, covering the
distance of 17 miles between Bouy and Rheims.  The next day,
Louis Bleriot, in flying from Toury to Artenay, made two
landings en route, this being the first cross-country flight
with landings.  On the last day of the year, Wilbur Wright won
the Michelin Cup at Auvours with a flight of 90 miles, which,
lasting 2 hours 20 minutes 23 seconds, exceeded 2 hours in the
air for the first time.

On January 2nd, 1909, S. F. Cody opened the New Year by making
the first observed flight at Farnborough on a British Army
aeroplane.  It was not until July 18th of 1909 that the first
European height record deserving of mention was put up by
Paulhan, who achieved a height of 450 feet on a Voisin
biplane.  This preceded Latham's first attempt to fly the
Channel by two days, and five days later, on the 25th of the
month, Bleriot made the first Channel crossing.  The Rheims
Meeting followed on August 22nd, and it was a great day for
aviation when nine machines were seen in the air at once.  It
was here that Farman, with a 118 mile flight, first exceeded
the hundred miles, and Latham raised the height record
officially to 500 feet, though actually he claimed to have
reached 1,200 feet.  On September 8th, Cody, flying from
Aldershot, made a 40 mile journey, setting up a new
cross-country record.  On October 19th the Comte de Lambert
flew from Juvisy to Paris, rounded the Eiffel Tower and flew
back.  J. T. C. Moore-Brabazon made the first circular mile
flight by a British aviator on an all-British machine in Great
Britain, on October 30th, flying a Short biplane with a Green
engine.  Paulhan, flying at Brooklands on November 2nd,
accomplished 96 miles in 2 hours 48 minutes, creating a British
distance record; on the following day, Henry Farman made a
flight of 150 miles in 4 hours 22 minutes at Mourmelon, and on
the 5th of the month, Paulhan, flying a Farman biplane, made a
world's height record of 977 feet.  This, however, was not to
stand long, for Latham got up to 1,560 feet on an Antoinette at
Mourmelon on December 1st.  December 31st witnessed the first
flight in Ireland, made by H. Ferguson on a monoplane which he
himself had constructed at Downshire Park, Lisburn.

These, thus briefly summarised, are the principal events up to
the end of 1909.  1910 opened with tragedy, for on January 4th
Leon Delagrange, one of the greatest pilots of his time, was
killed while flying at Pau.  The machine was the Bleriot XI which
Delagrange had used at the Doncaster meeting, and to which
Delagrange had fitted a 50 horse-power Gnome engine, increasing
the speed of the machine from its original 30 to 45 miles per
hour.  With the Rotary Gnome engine there was of necessity a
certain gyroscopic effect, the strain of which proved too much
for the machine.  Delagrange had come to assist in the
inauguration of the Croix d'Hins aerodrome, and had twice lapped
the course at a height of about 60 feet.  At the beginning of
the third lap, the strain of the Gnome engine became too great
for the machine; one wing collapsed as if the stay wires had
broken, and the whole machine turned over and fell, killing
Delagrange.

On January 7th Latham, flying at Mourmelon, first made the
vertical kilometre and dedicated the record to Delagrange, this
being the day of his friend's funeral.  The record was
thoroughly authenticated by a large registering barometer which
Latham carried, certified by the officials of the French Aero
Club.  Three days later Paulhan, who was at Los Angeles,
California, raised the height record to 4,146 feet.

On January 25th the Brussels Exhibition opened, when the
Antoinette monoplane, the Gaffaux and Hanriot monoplanes,
together with the d'Hespel aeroplane, were shown; there were
also the dirigible Belgica and a number of interesting aero
engines, including a German airship engine and a four-cylinder
50 horse-power Miesse, this last air-cooled by means of 22
fans driving a current of air through air jackets surrounding
fluted cylinders.

On April 2nd Hubert Le Blon, flying a Bleriot with an Anzani
engine, was killed while flying over the water.  His machine was
flying quite steadily, when it suddenly heeled over and came
down sideways into the sea; the motor continued running for some
seconds and the whole machine was drawn under water.  When boats
reached the spot, Le Blon was found lying back in the driving
seat floating just below the surface.  He had done good flying
at Doncaster, and at Heliopolis had broken the world's speed
records for 5 and 10 kilometres.  The accident was attributed
to fracture of one of the wing stay wires when running into a
gust of wind.

The next notable event was Paulhan's London-Manchester flight,
of which full details have already been given.  In May Captain
Bertram Dickson, flying at the Tours meeting, beat all the
Continental fliers whom he encountered, including Chavez, the
Peruvian, who later made the first crossing of the Alps. 
Dickson was the first British winner of international aviation
prizes.

C. S. Rolls, of whom full details have already been given, was
killed at Bournemouth on July 12th, being the first British
aviator of note to be killed in an aeroplane accident.  His
return trip across the Channel had taken place on June 2nd. 
Chavez, who was rapidly leaping into fame, as a pilot, raised
the British height record to 5,750 feet while flying at
Blackpool on August 3rd.  On the 11th of that month, Armstrong
Drexel, flying a Bleriot, made a world's height record of 6,745
feet.

It was in 1910 that the British War office first began fully to
realise that there might be military possibilities in
heavier-than-air flying.  C. S. Rolls had placed a Wright
biplane at the disposal of the military authorities, and Cody,
as already recorded, had been experimenting with a biplane type
of his own for some long period.  Such development as was
achieved was mainly due to the enterprise and energy of Colonel
J. E. Capper, C.B., appointed to the superintendency of the
Balloon Factory and Balloon School at Farnborough in 1906. 
Colonel Capper's retirement in 1910 brought (then) Mr Mervyn
O'Gorman to command, and by that time the series of successes of
the Cody biplane, together with the proved efficiency of the
aeroplane in various civilian meetings, had convinced the
British military authorities that the mastery of the air did not
lie altogether with dirigible airships, and it may be said that
in 1910 the British War office first began seriously to consider
the possibilities of the aeroplane, though two years more were
to elapse before the formation of the Royal Flying Corps marked
full realisation of its value.

A triumph and a tragedy were combined in September of 1910.  On
the 23rd of the month, Georges Chavez set out to fly across the
Alps on a Bleriot monoplane.  Prizes had been offered by the
Milan Aviation Committee for a flight from Brigue in Switzerland
over the Simplon Pass to Milan, a distance of 94 miles with a
minimum height of 6,600 feet above sea level.  Chavez started at
1.30 p.m.  On the 23rd, and 41 minutes later he reached
Domodossola, 25 miles distant.  Here he descended, numbed with
the cold of the journey; it was said that the wings of his
machine collapsed when about 30 feet from the ground, but
however this may have been, he smashed the machine on landing,
and broke both legs, in addition to sustaining other serious
injuries.  He lay in hospital until the 27th September, when he
died, having given his life to the conquest of the Alps.  His
death in the moment of success was as great a tragedy as were
those of Pilcher and Lilienthal.

The day after Chavez's death, Maurice Tabuteau flew across the
Pyrenees, landing in the square at Biarritz.  On December 30th,
Tabuteau made a flight of 365 miles in 7 hours 48 minutes. 
Farman, on December 18th, had flown for over 8 hours, but his
total distance was only 282 miles.  The autumn of this year was
also noteworthy for the fact that aeroplanes were first
successfully used in the French Military Manoeuvres.  The
British War Office, by the end of the year, had bought two
machines, a military type Farman and a Paulhan, ignoring British
experimenters and aeroplane builders of proved reliability. 
These machines, added to an old Bleriot two-seater, appear to
have constituted the British aeroplane fleet of the period.

There were by this time three main centres of aviation in
England, apart from Cody, alone on Laffan's Plain. These three
were Brooklands, Hendon, and the Isle of Sheppey, and of the
three Brooklands was chief.  Here such men as Graham Gilmour,
Rippen, Leake, Wickham, and Thomas persistently experimented. 
Hendon had its own little group, and Shellbeach, Isle of
Sheppey, held such giants of those days as C. S. Rolls and
Moore Brabazon, together with Cecil Grace and Rawlinson.  One or
other, and sometimes all of these were deserted on the occasion
of some meeting or other, but they were the points where the
spade work was done, Brooklands taking chief place.  'If you want
the early history of flying in England, it is there,' one of the
early school remarked, pointing over toward Brooklands course.

1911 inaugurated a new series of records of varying character. 
On the 17th January, E. B. Ely, an American, flew from the shore
of San Francisco to the U.S. cruiser Pennsylvania, landing on the
cruiser, and then flew back to the shore.  The British military
designing of aeroplanes had been taken up at Farnborough by G. H.
de Havilland, who by the end of January was flying a machine of
his own design, when he narrowly escaped becoming a casualty
through collision with an obstacle on the ground, which swept the
undercarriage from his machine.

A list of certified pilots of the countries of the world was
issued early in 1911, showing certificates granted up to the
end of 1910.  France led the way easily with 353 pilots; England
came next with 57, and Germany next with 46; Italy owned 32,
Belgium 27, America 26, and Austria 19; Holland and Switzerland
had 6 aviators apiece, while Denmark followed with 3, Spain with
2, and Sweden with 1.  The first certificate in England was that
of J. T. C. Moore-Brabazon, while Louis Bleriot was first on
the French list and Glenn Curtiss, first holder of an American
certificate, also held the second French brevet.

On the 7th March, Eugene Renaux won the Michelin Grand Prize by
flying from the French Aero Club ground at St Cloud and landing
on the Puy de Dome.  The landing, which was one of the
conditions of the prize, was one of the most dangerous
conditions ever attached to a competition; it involved dropping
on to a little plateau 150 yards square, with a possibility of
either smashing the machine against the face of the mountain, or
diving over the edge of the plateau into the gulf beneath.  The
length of the journey was slightly over 200 miles and the height
of the landing point 1,465 metres, or roughly 4,500 feet above
sea-level.  Renaux carried a passenger, Doctor Senoucque, a
member of Charcot's South Polar Expedition.

The 1911 Aero Exhibition held at Olympia bore witness to the
enormous strides made in construction, more especially by
British designers, between 1908 and the opening of the Show. 
The Bristol Firm showed three machines, including a military
biplane, and the first British built biplane with tractor screw. 
The Cody biplane, with its enormous size rendering it a
prominent feature of the show, was exhibited.  Its designer
anticipated later engines by expressing his desire for a motor
of 150 horse-power, which in his opinion was necessary to get
the best results from the machine.  The then famous Dunne
monoplane was exhibited at this show, its planes being V-shaped
in plan, with apex leading.  It embodied the results of very
lengthy experiments carried out both with gliders and
power-driven machines by Colonel Capper, Lieut. Gibbs, and
Lieut. Dunne, and constituted the longest step so far taken in
the direction of inherent stability.

Such forerunners of the notable planes of the war period as the
Martin Handasyde, the Nieuport, Sopwith, Bristol, and Farman
machines, were features of the show; the Handley-Page monoplane,
with a span of 32 feet over all, a length of 22 feet, and a
weight of 422 lbs., bore no relation at all to the twin-engined
giant which later made this firm famous.  In the matter of
engines, the principal survivals to the present day, of which
this show held specimens, were the Gnome, Green, Renault
air-cooled, Mercedes four-cylinder dirigible engine of 115
horse-power, and 120 horsepower Wolseley of eight cylinders for
use with dirigibles.

On April 12th, of 1911, Paprier, instructor at the Bleriot
school at Hendon, made the first non-stop flight between London
and Paris.  He left the aerodrome at 1.37 p.m., and arrived at
Issy-les-Moulineaux at 5.33 p.m., thus travelling 250 miles in a
little under 4 hours.  He followed the railway route practically
throughout, crossing from Dover to nearly opposite Calais,
keeping along the coast to Boulogne, and then following the Nord
Railway to Amiens, Beauvais, and finally Paris.

In May, the Paris-Madrid race took place; Vedrines, flying a
Morane biplane, carried off the prize by first completing the
distance of 732 miles.  The Paris-Rome race of 916 miles was won
in the same month by Beaumont, flying a Bleriot monoplane.  In
July, Koenig won the German National Circuit race of 1,168 miles
on an Albatross biplane.  This was practically simultaneous with
the Circuit of Britain won by Beaumont, who covered 1,010 miles
on a Bleriot monoplane, having already won the
Paris-Brussels-London-Paris Circuit of 1,080 miles, this also on
a Bleriot.  It was in August that a new world's height record of
11,152 feet was set up by Captain Felix at Etampes, while
on the 7th of the month Renaux flew nearly 600 miles on a
Maurice Farman machine in 12 hours.  Cody and Valentine were
keeping interest alive in the Circuit of Britain race, although
this had long been won, by determinedly plodding on at finishing
the course.

On September 9th, the first aerial post was tried between Hendon
and Windsor, as an experiment in sending mails by aeroplane. 
Gustave Hamel flew from Hendon to Windsor and back in a strong
wind.  A few days later, Hamel went on strike, refusing to carry
further mails unless the promoters of the Aerial Postal Service
agreed to pay compensation to Hubert, who fractured both his legs
on the 11th of the month while engaged in aero postal work.  The
strike ended on September 25th, when Hamel resumed mail-carrying
in consequence of the capitulation of the Postmaster-General, who
agreed to set aside L500 as compensation to Hubert.

September also witnessed the completion in America of a flight
across the Continent, a distance of 2,600 miles. The only
competitor who completed the full distance was C. P. Rogers,
who was disqualified through failing to comply with the time
limit.  Rogers needed so many replacements to his machine on the
journey that, expressing it in American fashion, he arrived with
practically a dfferent aeroplane from that with which he
started.

With regard to the aerial postal service, analysis of the matter
carried and the cost of the service seemed to show that with a
special charge of one shilling for letters and sixpence for post
cards, the revenue just balanced the expenditure.  It was not
possible to keep to the time-table as, although the trials were
made in the most favourable season of the year, aviation was not
sufficiently advanced to admit of facing all weathers and
complying with time-table regulations.

French military aeroplane trials took place at Rheims in
October, the noteworthy machines being Antoinette, Farman,
Nieuport, and Deperdussin.  The tests showed the Nieuport
monoplane with Gnome motor as first in position; the Breguet
biplane was second, and the Deperdussin monoplanes third.  The
first five machines in order of merit were all engined with the
Gnome motor.

The records quoted for 1911 form the best evidence that can
be given of advance in design and performance during the year. 
It will be seen that the days of the giants were over; design
was becoming more and more standardised and aviation not so much
a matter of individual courage and even daring, as of the
reliability of the machine and its engine.  This was the first
year in which the twin-engined aeroplane made its appearance,
and it was the year, too, in which flying may be said to have
grown so common that the 'meetings' which began with Rheims were
hardly worth holding, owing to the fact that increase in height
and distance flown rendered it no longer necessary for a
would-be spectator of a flight to pay half a crown and enter an
enclosure.  Henceforth, flying as a spectacle was very little to
be considered; its commercial aspects were talked of, and to a
very slight degree exploited, but, more and more, the fact that
the aeroplane was primarily an engine of war, and the growing
German menace against the peace of the world combined to point
the way of speediest development, and the arrangements for the
British Military Trials to be held in August, 1912, showed that
even the British War office was waking up to the potentialities
of this new engine of war.



XVIII. A SUMMARY, TO 1914

Consideration of the events in the years immediately preceding
the War must be limited to as brief a summary as possible, this
not only because the full history of flying achievements is
beyond the compass of any single book, but also because, viewing
the matter in perspective, the years 1903-1911 show up as far
more important as regards both design and performance.  From
1912 to August of 1914, the development of aeronautics was
hindered by the fact that it had not progressed far enough to
form a real commercial asset in any country.  The meetings which
drew vast concourses of people to such places as Rheims and
Bournemouth may have been financial successes at first, but, as
flying grew more common and distances and heights extended, a
great many people found it other than worth while to pay for
admission to an aerodrome.  The business of taking up passengers
for pleasure flights was not financially successful, and,
although schemes for commercial routes were talked of, the
aeroplane was not sufficiently advanced to warrant the
investment of hard cash in any of these projects.  There was a
deadlock; further development was necessary in order to secure
financial aid, and at the same time financial aid was necessary
in order to secure further development.  Consequently, neither
was forthcoming.

This is viewing the matter in a broad and general sense; there
were firms, especially in France, but also in England and
America, which looked confidently for the great days of flying to
arrive, and regarded their sunk capital as investment which would
eventually bring its due return.  But when one looks back on
those years, the firms in question stand out as exceptions to the
general run of people, who regarded aeronautics as something
extremely scientific, exceedingly dangerous, and very expensive. 
The very fame that was attained by such pilots as became
casualties conduced to the advertisement of every death, and the
dangers attendant on the use of heavier-than-air machines became
greatly exaggerated; considering the matter as one of number of
miles flown, even in the early days, flying exacted no more toll
in human life than did railways or road motors in the early
stages of their development.  But to take one instance, when C.
S. Rolls was killed at Bournemouth by reason of a faulty
tail-plane, the fact was shouted to the whole world with almost
as much vehemence as characterised the announcement of the
Titanic sinking in mid-Atlantic.

Even in 1911 the deadlock was apparent; meetings were falling
off in attendance, and consequently in financial benefit to the
promoters; there remained, however, the knowledge--for it was
proved past question--that the aeroplane in its then stage of
development was a necessity to every army of the world.  France
had shown this by the more than interest taken by the French
Government in what had developed into an Air Section of the
French army; Germany, of course, was hypnotised by Count
Zeppelin and his dirigibles, to say nothing of the Parsevals
which had been proved useful military accessories; in spite of
this, it was realised in Germany that the aeroplane also had its
place in military affairs.  England came into the field with the
military aeroplane trials of August 1st to 15th, 1912, barely two
months after the founding of the Royal Flying Corps.

When the R.F.C. was founded--and in fact up to two years after
its founding--in no country were the full military
potentialities of the aeroplane realised; it was regarded as an
accessory to cavalry for scouting more than as an independent
arm; the possibilities of bombing were very vaguely considered,
and the fact that it might be possible to shoot from an
aeroplane was hardly considered at all.  The conditions of the
British Military Trials of 1912 gave to the War office the
option of purchasing for L1,000 any machine that might be
awarded a prize.  Machines were required, among other things, to
carry a useful load of 350 lbs. in addition to equipment, with
fuel and oil for 4 1/2-hours; thus loaded, they were required to
fly for 3 hours, attaining an altitude of 4,500 feet, maintaining
a height of 1,500 feet for 1 hour, and climbing 1,000 feet from
the ground at a rate of 200 feet per minute, 'although 300 feet
per minute is desirable.'  They had to attain a speed of not less
than 55 miles per hour in a calm, and be able to plane down to
the ground in a calm from not more than 1,000 feet with engine
stopped, traversing 6,000 feet horizontal distance.  For those
days, the landing demands were rather exacting; the machine
should be able to rise without damage from long grass, clover, or
harrowed land, in 100 yards in a calm, and should be able to land
without damage on any cultivated ground, including rough ploughed
land, and, when landing on smooth turf in a calm, be able to pull
up within 75 yards of the point of first touching the ground.  It
was required that pilot and observer should have as open a view
as possible to front and flanks, and they should be so shielded
from the wind as to be able to communicate with each other. 
These are the main provisions out of the set of conditions laid
down for competitors, but a considerable amount of leniency was
shown by the authorities in the competition, who obviously wished
to try out every machine entered and see what were its
capabilities.

The beginning of the competition consisted in assembling the
machines against time from road trim to flying trim.  Cody's
machine, which was the only one to be delivered by air, took 1
hour and 35 minutes to assemble; the best assembling time was
that of the Avro, which was got into flying trim in 14 minutes 30
seconds.  This machine came to grief with Lieut. Parke as pilot,
on the 7th, through landing at very high speed on very bad
ground; a securing wire of the under-carriage broke in the
landing, throwing the machine forward on to its nose and then
over on its back.  Parke was uninjured, fortunately; the damaged
machine was sent off to Manchester for repair and was back again
on the 16th of August.

It is to be noted that by this time the Royal Aircraft Factory
was building aeroplanes of the B.E. and F.E. types, but at the
same time it is also to be noted that British military interest
in engines was not sufficient to bring them up to the high level
attained by the planes, and it is notorious that even the
outbreak of war found England incapable of providing a really
satisfactory aero engine.  In the 1912 Trials, the only machines
which actually completed all their tests were the Cody biplane,
the French Deperdussin, the Hanriot, two Bleriots and a Maurice
Farman.  The first prize of L4,000, open to all the world, went
to F. S. Cody's British-built biplane, which complied with all
the conditions of the competition and well earned its official
acknowledgment of supremacy.  The machine climbed at 280 feet per
minute and reached a height of 5,000 feet, while in the landing
test, in spite of its great weight and bulk, it pulled up on
grass in 56 yards.  The total weight was 2,690 lbs. when fully
loaded, and the total area of supporting surface was 500 square
feet; the motive power was supplied by a six-cylinder 120
horsepower Austro-Daimler engine.  The second prize was taken by
A. Deperdussin for the French-built Deperdussin monoplane.  Cody
carried off the only prize awarded for a British-built plane,
this being the sum of L1,000, and consolation prizes of L500 each
were awarded to the British Deperdussin Company and The British
and Colonial Aeroplane Company, this latter soon to become famous
as makers of the Bristol aeroplane, of which the war honours are
still fresh in men's minds.

While these trials were in progress Audemars accomplished the
first flight between Paris and Berlin, setting out from Issy
early in the morning of August 18th, landing at Rheims to refill
his tanks within an hour and a half, and then coming into bad
weather which forced him to land successively at Mezieres,
Laroche, Bochum, and finally nearly Gersenkirchen, where, owing
to a leaky petrol tank, the attempt to win the prize offered for
the first flight between the two capitals had to be abandoned
after 300 miles had been covered, as the time limit was
definitely exceeded.  Audemars determined to get through to
Berlin, and set off at 5 in the morning of the 19th, only to be
brought down by fog; starting off again at 9.15 he landed at
Hanover, was off again at 1.35, and reached the Johannisthal
aerodrome in the suburbs of Berlin at 6.48 that evening.

As early as 1910 the British Government possessed some ten
aeroplanes, and in 1911 the force developed into the Army Air
Battalion, with the aeroplanes under the control of Major J. H.
Fulton, R.F.A.  Toward the end of 1911 the Air Battalion was
handed over to (then) Brig.-Gen. D. Henderson, Director of
Military Training.  On June 6th, 1912, the Royal Flying Corps was
established with a military wing under Major F. H. Sykes and a
naval wing under Commander C. R. Samson.  A joint Naval and
Military Flying School was established at Upavon with Captain
Godfrey M. Paine, R.N., as Commandant and Major Hugh Trenchard
as Assistant Commandant.  The Royal Aircraft Factory brought out
the B.E. and F.E. types of biplane, admittedly superior to any
other British design of the period, and an Aircraft Inspection
Department was formed under Major J. H. Fulton.  The military
wing of the R.F.C. was equipped almost entirely with machines
of Royal Aircraft Factory design, but the Navy preferred to
develop British private enterprise by buying machines from
private firms.  On July 1st, 1914 the establishment of the Royal
Naval Air Service marked the definite separation of the military
and naval sides of British aviation, but the Central Flying
School at Upavon continued to train pilots for both services.

It is difficult at this length of time, so far as the military
wing was concerned, to do full justice to the spade work done by
Major-General Sir David Henderson in the early days.  Just before
war broke out, British military air strength consisted officially
of eight squadrons, each of 12 machines and 13 in reserve, with
the necessary complement of road transport.  As a matter of fact,
there were three complete squadrons and a part of a fourth which
constituted the force sent to France at the outbreak of war.  The
value of General Henderson's work lies in the fact that, in spite
of official stinginess and meagre supplies of every kind, he
built up a skeleton organisation so elastic and so well thought
out that it conformed to war requirements as well as even the
German plans fitted in with their aerial needs.  On the 4th of
August, 1914, the nominal British air strength of the military
wing was 179 machines.  Of these, 82 machines proceeded to
France, landing at Amiens and flying to Maubeuge to play their
part in the great retreat with the British Expeditionary Force,
in which they suffered heavy casualties both in personnel and
machines.  The history of their exploits, however, belongs to the
War period.

The development of the aeroplane between 1912 and 1914 can be
judged by comparison of the requirements of the British War
Office in 1912 with those laid down in an official memorandum
issued by the War Office in February, 1914.  This latter
called for a light scout aeroplane, a single-seater, with fuel
capacity to admit of 300 miles range and a speed range of from
50 to 85 miles per hour.  It had to be able to climb 3,500 feet
in five minutes, and the engine had to be so constructed that
the pilot could start it without assistance.  At the same time,
a heavier type of machine for reconnaissance work was called
for, carrying fuel for a 200 mile flight with a speed range of
between 35 and 60 miles per hour, carrying both pilot and
observer.  It was to be equipped with a wireless telegraphy set,
and be capable of landing over a 30 foot vertical obstacle and
coming to rest within a hundred yards' distance from the
obstacle in a wind of not more than 15 miles per hour.  A third
requirement was a heavy type of fighting aeroplane accommodating
pilot and gunner with machine gun and ammunition, having a speed
range of between 45 and 75 miles per hour and capable of
climbing 3,500 feet in 8 minutes.  It was required to carry fuel
for a 300 mile flight and to give the gunner a clear field of
fire in every direction up to 30 degrees on each side of the
line of flight.  Comparison of these specifications with those
of the 1912 trials will show that although fighting, scouting,
and reconnaissance types had been defined, the development of
performance compared with the marvellous development of the
earlier years of achieved flight was small.

Yet the records of those years show that here and there an
outstanding design was capable of great things. On the 9th
September, 1912, Vedrines, flying a Deperdussin monoplane at
Chicago, attained a speed of 105 miles an hour.  On August 12th,
G. de Havilland took a passenger to a height of 10,560 feet
over Salisbury Plain, flying a B.E. biplane with a 70
horse-power Renault engine.  The work of de Havilland may be
said to have been the principal influence in British military
aeroplane design, and there is no doubt that his genius was in
great measure responsible for the excellence of the early B.E. 
and F.E. types.

on the 31st May, 1913, H. G. Hawker, flying at Brooklands,
reached a height of 11,450 feet on a Sopwith biplane engined with
an 80 horse-power Gnome engine.  On June 16th, with the same type
of machine and engine, he achieved 12,900 feet.  On the 2nd
October, in the same year, a Grahame White biplane with 120
horse-power Austro-Daimler engine, piloted by Louis Noel, made a
flight of just under 20 minutes carrying 9 passengers.  In France
a Nieuport monoplane piloted by G. Legagneaux attained a height
of 6,120 metres, or just over 20,070 feet, this being the world's
height record.  It is worthy of note that of the world's aviation
records as passed by the International Aeronautical Federation up
to June 30th, 1914, only one, that of Noel, is credited to Great
Britain.

Just as records were made abroad, with one exception, so were
the really efficient engines.  In England there was the Green
engine, but the outbreak of war found the Royal Flying Corps
with 80 horse-power Gnomes, 70 horse-power Renaults, and one or
two Antoinette motors, but not one British, while the Royal
Naval Air Service had got 20 machines with engines of similar
origin, mainly land planes in which the wheeled undercarriages
had been replaced by floats.  France led in development, and
there is no doubt that at the outbreak of war, the French
military aeroplane service was the best in the world.  It was
mainly composed of Maurice Farman two-seater biplanes and
Bleriot monoplanes-- the latter type banned for a period on
account of a number of serious accidents that took place in 1912

America had its Army Aviation School, and employed Burgess-Wright
and Curtiss machines for the most part.  In the pre-war years,
once the Wright Brothers had accomplished their task, America's
chief accomplishment consisted in the development of the 'Flying 

Boat,' alternatively named with characteristic American
clumsiness, 'The Hydro-Aeroplane.'  In February of 1911, Glenn
Curtiss attached a float to a machine similar to that with which
he won the first Gordon-Bennett Air Contest and made his first
flying boat experiment.  From this beginning he developed the
boat form of body which obviated the use and troubles of
floats--his hydroplane became its own float.

Mainly owing to greater engine reliability the duration records
steadily increased.  By September of 1912 Fourny, on a Maurice
Farman biplane, was able to accomplish a distance of 628 miles
without a landing, remaining in the air for 13 hours 17 minutes
and just over 57 seconds.  By 1914 this was raised by the German
aviator, Landemann, to 21 hours 48 3/4 seconds.  The nature of
this last record shows that the factors in such a record had
become mere engine endurance, fuel capacity, and capacity of the
pilot to withstand air conditions for a prolonged period, rather
than any exceptional flying skill.

Let these years be judged by the records they produced, and even
then they are rather dull.  The glory of achievement such as
characterised the work of the Wright Brothers, of Bleriot, and
of the giants of the early days, had passed; the splendid
courage, the patriotism and devotion of the pilots of the War
period had not yet come to being.  There was progress, past
question, but it was mechanical, hardly ever inspired.  The
study of climatic conditions was definitely begun and
aeronautical meteorology came to being, while another development
already noted was the fitting of wireless telegraphy to
heavier-than-air machines, as instanced in the British War
office specification of February, 1914.  These, however, were
inevitable; it remained for the War to force development beyond
the inevitable, producing in five years that which under normal
circumstances might easily have occupied fifty --the aeroplane of
to-day; for, as already remarked, there was a deadlock, and any
survey that may be made of the years 1912-1914, no matter how
superficial, must take it into account with a view to retaining
correct perspective in regard to the development of the
aeroplane.

There is one story of 1914 that must be included, however
briefly, in any record of aeronautical achievement, since it
demonstrates past question that to Professor Langley really
belongs the honour of having achieved a design which would ensure
actual flight, although the series of accidents which attended
his experiments gave to the Wright Brothers the honour of first
leaving the earth and descending without accident in a
power-driven heavier-than-air machine.  In March, 1914, Glenn
Curtiss was invited to send a flying boat to Washington for the
celebration of 'Langley Day,' when he remarked, 'I would like to
put the Langley aeroplane itself in the air.'  In consequence of
this remark, Secretary Walcot of the Smithsonian Institution
authorised Curtiss to re-canvas the original Langley aeroplane
and launch it either under its own power or with a more recent
engine and propeller.  Curtiss completed this, and had the
machine ready on the shores of Lake Keuka, Hammondsport, N.Y., by
May.  The main object of these renewed trials was to show whether
the original Langley machine was capable of sustained free flight
with a pilot, and a secondary object was to determine more fully
the advantages of the tandem monoplane type; thus the aeroplane
was first  flown as nearly as possible in its original condition,
and then with such modifications as seemed desirable.  The only
difference made for the first trials consisted in fitting floats
with connecting trusses; the steel main frame, wings, rudders,
engine, and propellers were substantially as they had been in
1903.  The pilot had the same seat under the main frame and the
same general system of control.  He could raise or lower the
craft by moving the rear rudder up and down; he could steer
right or left by moving the vertical rudder.  He had no ailerons
nor wing-warping mechanism, but for lateral balance depended on
the dihedral angle of the wings and upon suitable movements of
his weight or of the vertical rudder.

After the adjustments for actual flight had been made in the
Curtiss factory, according to the minute descriptions contained
in the Langley Memoir on Mechanical Flight, the aeroplane was
taken to the shore of Lake Keuka, beside the Curtiss hangars,
and assembled for launching.  On a clear morning (May 28th) and
in a mild breeze, the craft was lifted on to the water by a
dozen men and set going, with Mr Curtiss at the steering wheel,
esconced in the little boat-shaped car under the forward part of
the frame.  The four-winged craft, pointed somewhat across the
wind, went skimming over the waveless, then automatically headed
into the wind, rose in level poise, soared gracefully for 150
feet, and landed softly on the water near the shore.  Mr Curtiss
asserted that he could have flown farther, but, being unused to
the machine, imagined that the left wings had more resistance
than the right.  The truth is that the aeroplane was perfectly
balanced in wing resistance, but turned on the water like a
weather vane, owing to the lateral pressure on its big rear
rudder.  Hence in future experiments this rudder was made
turnable about a vertical axis, as well as about the horizontal
axis used by Langley.  Henceforth the little vertical rudder
under the frame was kept fixed and inactive.[*]

That the Langley aeroplane was subsequently fitted with an 80
horse-power Curtiss engine and successfully flown is of little
interest in such a record as this, except for the fact that with
the weight nearly doubled by the new engine and accessories the
machine flew successfully, and demonstrated the perfection of
Langley's design by standing the strain.  The point that is of
most importance is that the design itself proved a success and
fully vindicated Langley's work.  At the same time, it would be
unjust to pass by the fact of the flight without according to
Curtiss due recognition of the way in which he paid tribute to
the genius of the pioneer by these experiments.

[*] Smithsonian Publications No. 2329.



XIX. THE WAR PERIOD--I

Full record of aeronautical progress and of the accomplishments
of pilots in the years of the War would demand not merely a
volume, but a complete library, and even then it would be barely
possible to pay full tribute to the heroism of pilots of the war
period.  There are names connected with that period of which the
glory will not fade, names such as Bishop, Guynemer, Boelcke,
Ball, Fonck, Immelmann, and many others that spring to mind as
one recalls the 'Aces' of the period.  In addition to the
pilots, there is the stupendous development of the
machines--stupendous when the length of the period in which it
was achieved is considered.

The fact that Germany was best prepared in the matter of
heavier-than-air service machines in spite of the German faith
in the dirigible is one more item of evidence as to who forced
hostilities.  The Germans came into the field with well over 600
aeroplanes, mainly two-seaters of standardised design, and with
factories back in the Fatherland turning out sufficient new
machines to make good the losses.  There were a few
single-seater scouts built for speed, and the two-seater
machines were all fitted with cameras and bomb-dropping gear. 
Manoeuvres had determined in the German mind what should be the
uses of the air fleet; there was photography of fortifications
and field works; signalling by Very lights; spotting for the
guns, and scouting for news of enemy movements.  The methodical
German mind had arranged all this beforehand, but had not allowed
for the fact that opponents might take counter-measures which
would upset the over-perfect mechanism of the air service just as
effectually as the great march on Paris was countered by the
genius of Joffre.

The French Air Force at the beginning of the War consisted of
upwards of 600 machines.  These, unlike the Germans, were not
standardised, but were of many and diverse types.  In order to
get replacements quickly enough, the factories had to work on
the designs they had, and thus for a long time after the
outbreak of hostilities standardisation was an impossibility. 
The versatility of a Latin race in a measure compensated for
this; from the outset, the Germans tried to overwhelm the French
Air Force, but failed, since they had not the numerical
superiority, nor--this equally a determining factor--the
versatility and resource of the French pilots.  They calculated
on a 50 per cent superiority to ensure success; they needed more
nearly 400 per cent, for the German fought to rule, avoiding
risks whenever possible, and definitely instructed to save both
machines and pilots wherever possible.  French pilots, on the
other hand, ran all the risks there were, got news of German
movements, bombed the enemy, and rapidly worked up a very
respectable antiaircraft force which, whatever it may have
accomplished in the way of hitting German planes, got on the
German pilots' nerves.

It has already been detailed how Britain sent over 82 planes as
its contribution to the military aerial force of 1914.  These
consisted of Farman, Caudron, and Short biplanes, together with
Bleriot, Deperdussin and Nieuport monoplanes, certain R.A.F. 
types, and other machines of which even the name barely survives
--the resourceful Yankee entitles them 'orphans.'  It is on
record that the work of providing spares might have been rather
complicated but for the fact that there were none.

There is no doubt that the Germans had made study of aerial
military needs just as thoroughly as they had perfected their
ground organisation.  Thus there were 21 illuminated aircraft
stations in Germany before the War, the most powerful being at
Weimar, where a revolving electric flash of over 27 million
candle-power was located.  Practically all German aeroplane
tests in the period immediately preceding the War were of a
military nature, and quite a number of reliability tests were
carried out just on the other side of the French frontier. 
Night flying and landing were standardised items in the German
pilot's course of instruction while they were still experimental
in other countries, and a system of signals was arranged which
rendered the instructional course as perfect as might be.

The Belgian contribution consisted of about twenty machines fit
for active service and another twenty which were more or less
useful as training machines.  The material was mainly French,
and the Belgian pilots used it to good account until German
numbers swamped them. France, and to a small extent England,
kept Belgian aviators supplied with machines throughout the War.

The Italian Air Fleet was small, and consisted of French machines
together with a percentage of planes of Italian origin, of which
the design was very much a copy of French types.  It was not
until the War was nearing its end that the military and naval
services relied more on the home product than on imports.  This
does not apply to engines, however, for the F.I.A.T. and S.C.A.T.

were equal to practically any engine of Allied make, both in
design and construction. 

Russia spent vast sums in the provision of machines:  the giant
Sikorsky biplane, carrying four 100 horsepower Argus motors,
was designed by a young Russian engineer in the latter part of
1913, and in its early trials it created a world's record by
carrying seven passengers for 1 hour 54 minutes.  Sikorsky also
designed several smaller machines, tractor biplanes on the lines
of the British B.E. type, which were very successful.  These
were the only home productions, and the imports consisted mainly
of French aeroplanes by the hundred, which got as far as the
docks and railway sidings and stayed there, while German
influence and the corruption that ruined the Russian Army helped
to lose the War.  A few Russian aircraft factories were got into
operation as hostilities proceeded, but their products were
negligible, and it is not on record that Russia ever learned to
manufacture a magneto.

The United States paid tribute to British efficiency by adopting
the British system of training for its pilots; 500 American
cadets were trained at the School of Military Aeronautics at
oxford, in order to form a nucleus for the American aviation
schools which were subsequently set up in the United States and
in France.  As regards production of craft, the designing of the
Liberty engine and building of over 20,000 aeroplanes within a
year proves that America is a manufacturing country, even under
the strain of war.

There were three years of struggle for aerial supremacy, the
combatants being England and France against Germany, and the
contest was neck and neck all the way.  Germany led at the
outset with the standardised two-seater biplanes manned by
pilots and observers, whose training was superior to that
afforded by any other nation, while the machines themselves were
better equipped and fitted with accessories.  All the early
German aeroplanes were designated Taube by the uninitiated, and
were formed with swept-back, curved wings very much resembling
the wings of a bird.  These had obvious disadvantages, but the
standardisation of design and mass production of the German
factories kept them in the field for a considerable period, and
they flew side by side with tractor biplanes of improved design. 
For a little time, the Fokker monoplane became a definite threat
both to French and British machines.  It was an improvement on
the Morane French monoplane, and with a high-powered engine it
climbed quickly and flew fast, doing a good deal of damage for a
brief period of 1915.  Allied design got ahead of it and finally
drove it out of the air.

German equipment at the outset, which put the Allies at a
disadvantage, included a hand-operated magneto engine-starter
and a small independent screw which, mounted on one of the main
planes, drove the dynamo used for the wireless set.  Cameras
were fitted on practically every machine; equipment included
accurate compasses and pressure petrol gauges, speed and height
recording instruments, bomb-dropping fittings and sectional
radiators which facilitated repairs and gave maximum engine
efficiency in spite of variations of temperature.  As counter to
these, the Allied pilots had resource amounting to impudence. 
In the early days they carried rifles and hand grenades and
automatic pistols.  They loaded their machines down, often at
their own expense, with accessories and fittings until their
aeroplanes earned their title of Christmas trees.  They played
with death in a way that shocked the average German pilot of the
War's early stages, declining to fight according to rule and
indulging in the individual duels of the air which the German
hated.  As Sir John French put it in one of his reports, they
established a personal ascendancy over the enemy, and in this
way compensated for their inferior material.

French diversity of design fitted in well with the initiative
and resource displayed by the French pilots. The big Caudron
type was the ideal bomber of the early days; Farman machines
were excellent for reconnaissance and artillery spotting; the
Bleriots proved excellent as fighting scouts and for aerial
photography; the Nieuports made good fighters, as did the Spads,
both being very fast craft, as were the Morane-Saulnier
monoplanes, while the big Voisin biplanes rivalled the Caudron
machines as bombers.

The day of the Fokker ended when the British B.E.2.C. aeroplane
came to France in good quantities, and the F.E. type, together
with the De Havilland machines, rendered British aerial
superiority a certainty.  Germany's best reply--this was about
1916--was the Albatross biplane, which was used by Captain Baron
von Richthofen for his famous travelling circus, manned by
German star pilots and sent to various parts of the line to
hearten up German troops and aviators after any specially bad
strafe.  Then there were the Aviatik biplane and the Halberstadt
fighting scout, a cleanly built and very fast machine with a
powerful engine with which Germany tried to win back superiority
in the third year of the War, but Allied design kept about three
months ahead of that of the enemy, once the Fokker had been
mastered, and the race went on.  Spads and Bristol fighters,
Sopwith scouts and F.E.'s played their part in the race, and
design was still advancing when peace came.

The giant twin-engined Handley-Page bomber was tried out, proved
efficient, and justly considered better than anything of its
kind that had previously taken the field.  Immediately after the
conclusion of its trials, a specimen of the type was delivered
intact at Lille for the Germans to copy, the innocent pilot
responsible for the delivery doing some great disservice to his
own cause.  The Gotha Wagon-Fabrik Firm immediately set to work
and copied the Handley-Page design, producing the great Gotha
bombing machine which was used in all the later raids on England
as well as for night work over the Allied lines.

How the War advanced design may be judged by comparison of the
military requirements given for the British Military Trials of
1912, with performances of 1916 and 1917, when the speed of the
faster machines had increased to over 150 miles an hour and
Allied machines engaged enemy aircraft at heights ranging up to
22,000 feet.  All pre-war records of endurance, speed, and climb
went by the board, as the race for aerial superiority went on.

Bombing brought to being a number of crude devices in the first
year of the War.  Allied pilots of the very early days carried up
bombs packed in a small box and threw them over by hand, while, a
little later, the bombs were strung like apples on wings and
undercarriage, so that the pilot who did not get rid of his load
before landing risked an explosion.  Then came a properly
designed carrying apparatus, crude but fairly efficient, and with
1916 development had proceeded as far as the proper bomb-racks
with releasing gear.

Reconnaissance work developed, so that fighting machines went as
escort to observing squadrons and scouting operations were
undertaken up to 100 miles behind the enemy lines; out of this
grew the art of camouflage, when ammunition dumps were painted
to resemble herds of cows, guns were screened by foliage or
painted to merge into a ground scheme, and many other schemes
were devised to prevent aerial observation.  Troops were moved by
night for the most part, owing to the keen eyes of the air
pilots and the danger of bombs, though occasionally the aviator
had his chance.  There is one story concerning a British pilot
who, on returning from a reconnaissance flight, observed a
German Staff car on the road under him; he descended and bombed
and machine--gunned the car until the German General and his
chauffeur abandoned it, took to their heels, and ran like
rabbits.  Later still, when Allied air superiority was assured,
there came the phase of machine-gunning bodies of enemy troops
from the air.  Disregarding all antiaircraft measures, machines
would sweep down and throw battalions into panic or upset the
military traffic along a road, demoralising a battery or a
transport train and causing as much damage through congestion of
traffic as with their actual machine-gun fire.  Aerial
photography, too, became a fine art; the ordinary long focus
cameras were used at the outset with automatic plate changers,
but later on photographing aeroplanes had cameras of wide angle
lens type built into the fuselage. These were very simply
operated, one lever registering the exposure and changing the
plate.  In many cases, aerial photographs gave information which
the human eye had missed, and it is noteworthy that photographs
of ground showed when troops had marched over it, while the
aerial observer was quite unable to detect the marks left by
their passing.

Some small mention must be made of seaplane activities, which,
round the European coasts involved in the War, never ceased. 
The submarine campaign found in the spotting seaplane its
greatest deterrent, and it is old news now how even the deeply
submerged submarines were easily picked out for destruction from
a height and the news wirelessed from seaplane to destroyer,
while in more than one place the seaplane itself finished the
task by bomb dropping.  It was a seaplane that gave Admiral
Beatty the news that the whole German Fleet was out before the
Jutland Battle, news which led to a change of plans that very
nearly brought about the destruction of Germany's naval power. 
For the most part, the seaplanes of the War period were heavier
than the land machines and, in the opinion of the land pilots,
were slow and clumsy things to fly.  This was inevitable, for
their work demanded more solid building and greater reliability. 
To put the matter into Hibernian phrase, a forced landing at sea
is a much more serious matter than on the ground. Thus  there
was need for greater engine power, bigger wingspread to support
the floats, and fuel tanks of greater capacity.  The flying
boats of the later War period carried considerable crews, were
heavily armed, capable of withstanding very heavy weather, and
carried good loads of bombs on long cruises.  Their work was not
all essentially seaplane work, for the R.N.A.S. was as well
known as hated over the German airship sheds in Belgium and
along the Flanders coast.  As regards other theatres of War,
they rendered valuable service from the Dardanelles to the
Rufiji River, at this latter place forming a principal factor in
the destruction of the cruiser Konigsberg.  Their spotting work
at the Dardanelles for the battleships was responsible for
direct hits from 15 in. guns on invisible targets at ranges of
over 12,000 yards.  Seaplane pilots were bombing specialists,
including among their targets army headquarters, ammunition
dumps, railway stations, submarines and their bases, docks,
shipping in German harbours, and the German Fleet at
Wilhelmshaven.  Dunkirk, a British seaplane base, was a sharp
thorn in the German side.

Turning from consideration of the various services to the
exploits of the men composing them, it is difficult to
particularise.  A certain inevitable prejudice even at this
length of time leads one to discount the valour of pilots in the
German Air Service, but the names of Boelcke, von Richthofen,
and Immelmann recur as proof of the courage that was not wanting
in the enemy ranks, while, however much we may decry the Gotha
raids over the English coast and on London, there is no doubt
that the men who undertook these raids were not deficient in the
form of bravery that is of more value than the unthinking valour
of a minute which, observed from the right quarter, wins a
military decoration.

Yet the fact that the Allied airmen kept the air at all in the
early days proved on which side personal superiority lay, for
they were outnumbered, out-manoeuvred, and faced by better
material than any that they themselves possessed; yet they won
their fights or died.  The stories of their deeds are endless;
Bishop, flying alone and meeting seven German machines and
crashing four; the battle of May 5th, 1915, when five heroes
fought and conquered twenty-seven German machines, ranging in
altitude between 12,000 and 3,000 feet, and continuing the
extraordinary struggle from five until six in the evening.
Captain Aizlewood, attacking five enemy machines with such
reckless speed that he rammed one and still reached his
aerodrome safely--these are items in a long list of feats of
which the character can only be realised when it is fully
comprehended that the British Air Service accounted for some
8,ooo enemy machines in the course of the War.  Among the French
there was Captain Guynemer, who at the time of his death had
brought down fifty-four enemy machines, in addition to many
others of which the destruction could not be officially
confirmed.  There was Fonck, who brought down six machines in
one day, four of them within two minutes.

There are incredible stories, true as incredible, of shattered
men carrying on with their work in absolute disregard of
physical injury.  Major Brabazon Rees, V.C., engaged a big
German battle-plane in September of 1915 and, single-handed,
forced his enemy out of action.  Later in his career, with a
serious wound in the thigh from which blood was pouring, he kept
up a fight with an enemy formation until he had not a round of
ammunition left, and then returned to his aerodrome to get his
wound dressed.  Lieutenants Otley and Dunning, flying in the
Balkans, engaged a couple of enemy machines and drove them off,
but not until their petrol tank had got a hole in it and Dunning
was dangerously wounded in the leg.  Otley improvised a
tourniquet, passed it to Dunning, and, when the latter had
bandaged himself, changed from the observer's to the pilot's
seat, plugged the bullet hole in the tank with his thumb and
steered the machine home.

These are incidents; the full list has not been, and can never
be recorded, but it goes to show that in the pilot of the War
period there came to being a new type of humanity, a product of
evolution which fitted a certain need.  Of such was Captain
West, who, engaging hostile troops, was attacked by seven
machines.  Early in the engagement, one of his legs was
partially severed by an explosive bullet and fell powerless into
the controls, rendering the machine for the time unmanageable. 
Lifting his disabled leg, he regained control of the machine,
and although wounded in the other leg, he manoeuvred his machine
so skilfully that his observer was able to get several good
bursts into the enemy machines, driving them away.  Then,
desperately wounded as he was, Captain West brought the machine
over to his own lines and landed safely.  He fainted from loss
of blood and exhaustion, but on regaining consciousness,
insisted on writing his report.  Equal to this was the exploit
of Captain Barker, who, in aerial combat, was wounded in the
right and left thigh and had his left arm shattered,
subsequently bringing  down an enemy machine in flames, and then
breaking through another hostile formation and reaching the
British lines.

In recalling such exploits as these, one is tempted on and on,
for it seems that the pilots rivalled each other in their
devotion to duty, this not confined to British aviators, but
common practically to all services.  Sufficient instances have
been given to show the nature of the work and the character of
the men who did it.

The rapid growth of aerial effort rendered it necessary in
January of 1915 to organise the Royal Flying Corps into
separate wings, and in October of the same year it was
constituted in Brigades.  In 1916 the Air Board was formed,
mainly with the object of co-ordinating effort and ensuring both
to the R.N.A.S. and to the R.F.C. adequate supplies of material
as far as construction admitted.  Under the presidency of Lord
Cowdray, the Air Board brought about certain reforms early in
1917, and in November of that year a separate Air Ministry was
constituted, separating the Air Force from both Navy and Army,
and rendering it an independent force.  On April 1st, 1918, the
Royal Air Force came into existence, and unkind critics in the
Royal Flying Corps remarked on the appropriateness of the date. 
At the end of the War, the personnel of the Royal Air Force
amounted to 27,906 officers, and 263,842 other ranks.  Contrast
of these figures with the number of officers and men who took
the field in 1914 is indicative of the magnitude of British
aerial effort in the War period.



XX. THE WAR PERIOD--II

There was when War broke out no realisation on the part of the
British Government of the need for encouraging the enterprise of
private builders, who carried out their work entirely at
their-own cost.  The importance of a supply of British-built
engines was realised before the War, it is true, and a
competition was held in which a prize of L5,000 was offered for
the best British engine, but this awakening was so late that the
R.F.C. took the field without a single British power plant.
Although Germany woke up equally late to the need for home
produced aeroplane engines, the experience gained in building
engines for dirigibles sufficed for the production of aeroplane
power plants.  The Mercedes filled all requirements together
with the Benz and the Maybach.  There was a 225 horsepower Benz
which was very popular, as were the 100 horse-power and 170
horse-power Mercedes, the last mentioned fitted to the Aviatik
biplane of 1917.  The Uberursel was a copy of the Gnome and
supplied the need for rotary engines.

In Great Britain there were a number of aeroplane constructing
firms that had managed to emerge from the lean years 1912-1913
with sufficient manufacturing plant to give a hand in making up
the leeway of construction when War broke out.  Gradually the
motor-car firms came in, turning their body-building departments
to plane and fuselage construction, which enabled them to turn
out the complete planes engined and ready for the field.  The
coach-building trade soon joined in and came in handy as
propeller makers; big upholstering and furniture firms and scores
of concerns that had never dreamed of engaging in aeroplane
construction were busy on supplying the R.F.C.  By 1915 hundreds
of different firms were building aeroplanes and parts; by 1917
the number had increased to over 1,000, and a capital of over a
million pounds for a firm that at the outbreak of War had
employed a score or so of hands was by no means uncommon.  Women
and girls came into the work, more especially in plane
construction and covering and doping, though they took their
place in the engine shops and proved successful at acetylene
welding and work at the lathes.  It was some time before Britain
was able to provide its own magnetos, for this key industry had
been left in the hands of the Germans up to the outbreak of War,
and the 'Bosch' was admittedly supreme--even now it has never
been beaten, and can only be equalled, being as near perfection
as is possible for a magneto.

One of the great inventions of the War was the synchronisation
of engine-timing and machine gun, which rendered it possible to
fire through the blades of a propeller without damaging them,
though the growing efficiency of the aeroplane as a whole and of
its armament is a thing to marvel at on looking back and
considering what was actually accomplished.  As the efficiency
of the aeroplane increased, so anti-aircraft guns and
range-finding were improved.  Before the War an aeroplane
travelling at full speed was reckoned perfectly safe at 4,000
feet, but, by the first month of 1915, the safe height had gone
up to 9,000 feet, 7,000 feet being the limit of rifle and machine
gun bullet trajectory; the heavier guns were not sufficiently
mobile to tackle aircraft.  At that time, it was reckoned that
effective aerial photography ceased at 6,000 feet, while
bomb-dropping from 7,000-8,000 feet was reckoned uncertain except
in the case of a very large target.  The improvement in
anti-aircraft devices went on, and by May of 1916, an aeroplane
was not safe under 15,000 feet, while anti-aircraft shells had
fuses capable of being set to over 20,000 feet, and bombing from
15,000 and 16,000 feet was common.  It was not till later that
Allied pilots demonstrated the safety that lies in flying very
near the ground, this owing to the fact that, when flying swiftly
at a very low altitude, the machine is out of sight almost before
it can be aimed at.

The Battle of the Somme and the clearing of the air preliminary
to that operation brought the fighting aeroplane pure and simple
with them.  Formations of fighting planes preceded reconnaissance
craft in order to clear German machines and observation balloons
out of the sky and to watch and keep down any further enemy
formations that might attempt to interfere with Allied
observation work.  The German reply to this consisted in the
formation of the Flying Circus, of which Captain Baron von
Richthofen's was a good example.  Each circus consisted of a
large formation of speedy machines, built specially for fighting
and manned by the best of the German pilots.  These were sent to
attack at any point along the line where the Allies had got a
decided superiority.

The trick flying of pre-war days soon became an everyday matter;
Pegoud astonished the aviation world before the War by first
looping the loop, but, before three years of hostilities had
elapsed, looping was part of the training of practically every
pilot, while the spinning nose dive, originally considered fatal,
was mastered, and the tail slide, which consisted of a machine
rising nose upward in the air and falling back on its tail,
became one of the easiest 'stunts' in the pilot's repertoire. 
Inherent stability was gradually improved, and, from 1916 onward,
practically every pilot could carry on with his machine-gun or
camera and trust to his machine to fly itself until he was free
to attend to it.  There was more than one story of a machine
coming safely to earth and making good landing on its own account
with the pilot dead in his cock-pit.

Toward the end of the War, the Independent Air Force was formed
as a branch of the R.A.F. with a view to bombing German bases
and devoting its attention exclusively to work behind the enemy
lines.  Bombing operations were undertaken by the R.N.A.S. as
early as 1914-1915 against Cuxhaven, Dusseldorf, and
Friedrichshavn, but the supply of material was not sufficient to
render these raids continuous.  A separate Brigade, the 8th, was
formed in 1917 to harass the German chemical and iron
industries, the base being in the Nancy area, and this policy
was found so fruitful that the Independent Force was constituted
on the 8th June, 1918.  The value of the work accomplished by
this force is demonstrated by the fact that the German High
Command recalled twenty fighting squadrons from the Western
front to counter its activities, and, in addition, took troops
away from the fighting line in large numbers for manning
anti-aircraft batteries and searchlights.  The German press of
the last year of the War is eloquent of the damage done in
manufacturing areas by the Independent Force, which, had
hostilities continued a little longer, would have included Berlin
in its activities.

Formation flying was first developed by the Germans, who made
use of it in the daylight raids against England in 1917.  Its
value was very soon realised, and the V formation of wild geese
was adopted, the leader taking the point of the V and his
squadron following on either side at different heights.  The air
currents set up by the leading machines were thus avoided by
those in the rear, while each pilot had a good view of the
leader's bombs, and were able to correct their own aim by the
bursts, while the different heights at which they flew rendered
anti-aircraft gun practice less effective.  Further, machines
were able to afford mutual protection to each other and any
attacker would be met by machine-gun fire from three or four
machines firing on him from different angles and heights.  In
the later formations single-seater fighters flew above the
bombers for the purpose of driving off hostile craft.  Formation
flying was not fully developed when the end of the War brought
stagnation in place of the rapid advance in the strategy and
tactics of military air work.



XXI. RECONSTRUCTION

The end of the War brought a pause in which the multitude of
aircraft constructors found themselves faced with the possible
complete stagnation of the industry, since military activities
no longer demanded their services and the prospects of
commercial flying were virtually nil.  That great factor in
commercial success, cost of plant and upkeep, had received no
consideration whatever in the War period, for armies do not
count cost. The types of machines that had evolved from the War
were very fast, very efficient, and very expensive, although the
bombers showed promise of adaptation to commercial needs, and,
so far as other machines were concerned, America had already
proved the possibilities of mail-carrying by maintaining a mail
service even during the War period.

A civil aviation department of the Air Ministry was formed in
February of 1919  with a Controller General of Civil Aviation
at the head.  This was organised into four branches, one dealing
with the survey and preparation of air routes for the British
Empire, one organising meteorological and wireless telegraphy
services, one dealing with the licensing of aerodromes, machines
for passenger or goods carrying and civilian pilots, and one
dealing with publicity and transmission of information
generally.  A special Act of Parliament 264 entitled 'The Air
Navigation Acts, 1911-1919,' was passed on February 27th, and
commercial flying was officially permitted from May 1st, 1919.

Meanwhile the great event of 1919, the crossing of the
Atlantic by air, was gradually ripening to performance.  In
addition to the rigid airship, R.34, eight machines entered for
this flight, these being a Short seaplane, Handley-Page,
Martinsyde, Vickers-Vimy, and Sopwith aeroplanes, and three
American flying boats, N.C.1, N.C.3, and N.C.4.  The Short
seaplane was the only one of the eight which proposed to make
the journey westward; in flying from England to Ireland, before
starting on the long trip to Newfoundland, it fell into the sea
off the coast of Anglesey, and so far as it was concerned the
attempt was abandoned.

The first machines to start from the Western end were the three
American seaplanes, which on the morning of May 6th left
Trepassy, Newfoundland, on the 1,380 mile stage to Horta in the
Azores.  N.C.1 and N.C.3 gave up the attempt very early, but
N.C.4, piloted by Lieut.-Commander Read, U.S.N., made Horta on
May 17th and made a three days' halt.  On the 20th the second
stage of the journey to Ponta Delgada, a further 190 miles, was
completed and a second halt of a week was made.  On the 27th,
the machine left for Lisbon, 900 miles distant, and completed
the journey in a day.  On the 30th a further stage of 340 miles
took N.C.4 on to Ferrol, and the next day the last stage of 420
miles to Plymouth was accomplished.

Meanwhile, H. G. Hawker, pilot of the Sopwith biplane, together
with Commander Mackenzie Grieve, R.N., his navigator, found the
weather sufficiently auspicious to set out at 6.48 p.m.  On
Sunday, May 18th, in the hope of completing the trip by the
direct route before N.C.4 could reach Plymouth.  They set out
from Mount Pearl aerodrome, St John's, Newfoundland, and vanished
into space, being given up as lost, as Hamel was lost immediately
before the War in attempting to fly the North Sea.  There was a
week of dead silence regarding their fate, but on the following
Sunday morning there was world-wide relief at the news that the
plucky attempt had not ended in disaster, but both aviators had
been picked up by the steamer Mary at 9.30 a.m. on the morning of
the 19th, while still about 750 miles short of the conclusion of
their journey.  Engine failure brought them down, and they planed
down to the sea close to the Mary to be picked up; as the vessel
was not fitted with wireless, the news of their rescue could not
be communicated until land was reached.  An equivalent of half
the L10,000 prize offered by the Daily Mail for the non-stop
flight was presented by the paper in recognition of the very
gallant attempt, and the King conferred the Air Force Cross on
both pilot and navigator.

Raynham, pilot of the Martinsyde competing machine, had the bad
luck to crash his craft twice in attempting to start before he
got outside the boundary of the aerodrome.  The Handley-Page
machine was withdrawn from the competition, and, attempting to
fly to America, was crashed on the way.

The first non-stop crossing was made on June 14th-15th in 16
hours 27 minutes, the speed being just over 117 miles per hour. 
The machine was a Vickers-Vimy bomber, engined with two
Rolls-Royce Eagle VIII's, piloted by Captain John Alcock, D.S.C.,
with Lieut. Arthur Whitten-Brown as navigator.  The journey  was
reported to be very rough, so much so at times that Captain
Alcock stated that they were flying upside down, and for the
greater part of the time they were out of sight of the sea.  Both
pilot and navigator had the honour of knighthood conferred on
them at the conclusion of the journey.

Meanwhile, commercial flying opened on May 8th (the official
date was May 1st) with a joy-ride service from Hounslow of Avro
training machines.  The enterprise caught on remarkably, and the
company extended their activities to coastal resorts for the
holiday season--at Blackpool alone they took up 10,000
passengers before the service was two months old.  Hendon,
beginning passenger flights on the same date, went in for
exhibition and passenger flying, and on June 21st the aerial
Derby was won by Captain Gathergood on an Airco 4R machine with
a Napier 450 horse-power 'Lion' engine; incidentally the speed
of 129.3 miles per hour was officially recognised as constituting
the world's record for speed within a closed circuit.  On July
17th a Fiat B.R. biplane with a 700 horse-power engine landed at
Kenley aerodrome after having made a non-stop flight of 1,100
miles.  The maximum speed of this machine was 160 miles per
hour, and it was claimed to be the fastest machine in existence. 
On August 25th a daily service between London and Paris was
inaugurated by the Aircraft Manufacturing Company, Limited, who
ran a machine each way each day, starting at 12.30 and due to
arrive at 2.45 p.m.  The Handley-Page Company began a similar
service in September of 1919, but ran it on alternate days
with machines capable of accommodating ten passengers.  The
single fare in each case was fixed at 15 guineas and the parcel
rate at 7s. 6d. per pound.

Meanwhile, in Germany, a number of passenger services had been
in operation from the early part of the year; the Berlin-Weimar
service was established on February 5th and Berlin-Hamburg on
March 1st, both for mail and passenger carrying.  Berlin-Breslau
was soon added, but the first route opened remained most
popular, 538 flights being made between its opening and the
end of April, while for March and April combined, the
Hamburg-Berlin route recorded only 262 flights.  All three
routes were operated by a combine of German aeronautical firms
entitled the Deutsch Luft Rederie.  The single fare between
Hamburg and Berlin was 450 marks, between Berlin and Breslau 500
marks, and between Berlin and Weimar 450 marks.  Luggage was
carried free of charge, but varied according to the weight of
the passenger, since the combined weight of both passenger and
luggage was not allowed to exceed a certain limit.

In America commercial flying had begun in May of 1918 with the
mail service between Washington, Philadelphia, and New York,
which proved that mail carrying is a commercial possibility, and
also demonstrated the remarkable reliability of the modern
aeroplane by making 102 complete flights out of a possible total
of 104 in November, 1918, at a cost of 0.777 of a dollar per
mile.  By March of 1919 the cost per mile had gone up to 1.28
dollars; the first annual report issued at the end of May showed
an efficiency of 95.6 per cent and the original six aeroplanes
and engines with which the service began were still in regular
use.

In June of 1919 an American commercial firm chartered an
aeroplane for emergency service owing to a New York harbour
strike and found it so useful that they made it a regular
service.  The Travellers Company inaugurated a passenger flying
boat service between New York and Atlantic City on July 25th, the
fare, inclusive of 35 lbs. of luggage, being fixed at L25 each
way.

Five flights on the American continent up to the end of 1919
are worthy of note.  On December 13th, 1918, Lieut. D. Godoy of
the Chilian army left Santiago, Chili, crossed the Andes at a
height of 19,700 feet and landed at Mendoza, the capital of the
wine-growing province of Argentina.  On April 19th, 1919, Captain
E. F. White made the first non-stop flight between New York and
Chicago in 6 hours 50 minutes on a D.H.4 machine driven by a
twelve-cylinder Liberty engine.  Early in August Major Schroeder,
piloting a French Lepere machine flying at a height of 18,400
feet, reached a speed of 137 miles per hour with a Liberty motor
fitted with a super-charger.  Toward the end of August, Rex
Marshall, on a Thomas-Morse biplane, starting from a height of
17,000 feet, made a glide of 35 miles with his engine cut off,
restarting it when at a height of 600 feet above the ground. 
About a month later R. Rohlfe, piloting a Curtiss triplane, broke
the height record by reaching 34,610 feet.



XXII.  1919-20

Into the later months of 1919 comes the flight by Captain
Ross-Smith from England to Australia and the attempt to make the
Cape to Cairo voyage by air.  The Australian Government had
offered a prize of L10,000 for the first flight from England to
Australia in a British machine, the flight to be accomplished in
720 consecutive hours.  Ross-Smith, with his brother, Lieut.
Keith Macpherson Smith, and two mechanics, left Hounslow in a
Vickers-Vimy bomber with Rolls-Royce engine on November 12th and
arrived at Port Darwin, North Australia, on the 10th December,
having completed the flight in 27 days 20 hours 20 minutes, thus
having 51 hours 40 minutes to spare out of the 720 allotted
hours.

Early in 1920 came a series of attempts at completing the
journey by air between Cairo and the Cape.  Out of four
competitors Colonel Van Ryneveld came nearest to making the
journey successfully, leaving England on a standard Vickers-Vimy
bomber with Rolls-Royce engines, identical in design with the
machine used by Captain Ross-Smith on the England to Australia
flight.  A second Vickers-Vimy was financed by the Times
newspaper and a third flight was undertaken with a Handley-Page
machine under the auspices of the Daily Telegraph.  The Air
Ministry had already prepared the route by means of three survey
parties which cleared the aerodromes and landing grounds,
dividing their journey into stages of 200 miles or less.  Not
one of the competitors completed the course, but in both this
and Ross-Smith's flight valuable data was gained in respect of
reliability of machines and engines, together with a mass of
meteorological information.

The Handley-Page Company announced in the early months of 1920
that they had perfected a new design of wing which brought about
a twenty to forty per cent improvement in lift rate in the year. 
When the nature of the design was made public, it was seen to
consist of a division of the wing into small sections, each with
its separate lift.  A few days later, Fokker, the Dutch
inventor, announced the construction of a machine in which all
external bracing wires are obviated, the wings being of a very
deep section and self-supporting.  The value of these two
inventions remains to be seen so far as commercial flying is
concerned.

The value of air work in war, especially so far as the Colonial
campaigns in which British troops are constantly being engaged is
in question, was very thoroughly demonstrated in a report issued
early in 1920 with reference to the successful termination of the
Somaliland campaign through the intervention of the Royal Air
Force, which between January 21st and the 31st practically
destroyed the Dervish force under the Mullah, which had been a
thorn in the side of Britain since 1907.  Bombs and machine-guns
did the work, destroying fortifications and bringing about the
surrender of all the Mullah's following, with the exception of
about seventy who made their escape.

Certain records both in construction and performance had
characterised the post-war years, though as design advances and
comes nearer to perfection, it is obvious that records must get
fewer and farther between.  The record aeroplane as regards size
at the time of its construction was the Tarrant triplane, which
made its first--and last--flight on May 28th, 1919.  The total
loaded weight was 30 tons, and the machine was fitted with six
400 horse-power engines; almost immediately after the trial
flight began, the machine pitched forward on its nose and was
wrecked, causing fatal injuries to Captains Dunn and Rawlings,
who were aboard the machine.  A second accident of similar
character was that which befell the giant seaplane known as the
Felixstowe Fury, in a trial flight.  This latter machine was
intended to be flown to Australia, but was crashed over the
water.

On May 4th, 1920, a British record for flight duration and
useful load was established by a commercial type Handley-Page
biplane, which, carrying a load of 3,690 lbs., rose to a height
of 13,999 feet and remained in the air for 1 hour 20 minutes. 
On May 27th the French pilot, Fronval, flying at Villacoublay in
a Morane-Saulnier type of biplane with Le Rhone motor, put up an
extraordinary type of record by looping the loop 962 times in 3
hours 52 minutes 10 seconds.  Another record of the year of
similar nature was that of two French fliers, Boussotrot and
Bernard, who achieved a continuous flight of 24 hours 19 minutes
7 seconds, beating the pre-war record of 21 hours 48 3/4 seconds
set up by the German pilot, Landemann.  Both these records are
likely to stand, being in the nature of freaks, which demonstrate
little beyond the reliability of the machine and the capacity for
endurance on the part of its pilots.

Meanwhile, on February 14th, Lieuts. Masiero and Ferrarin left
Rome on S.V.A. Ansaldo V. machines fitted with 220 horse-power
S.V.A. motors.  On May 30th they arrived at Tokio, having flown
by way of Bagdad, Karachi, Canton, Pekin, and Osaka.  Several
other competitors started, two of whom were shot down by Arabs in
Mesopotamia.

Considered in a general way, the first two years after the
termination of the Great European War form a period of transition
in which the commercial type of aeroplane was gradually evolved
from the fighting machine which was perfected in the four
preceding years.  There was about this period no  sense of
finality, but it was as experimental, in its own way, as were the
years of progressing design which preceded the war period.  Such
commercial schemes as were inaugurated call for no more note than
has been given here; they have been experimental, and, with the
possible exception of the United States Government mail service,
have not been planned and executed on a sufficiently large scale
to furnish reliable data on which to forecast the prospects of
commercial aviation.  And there is a school rapidly growing up
which asserts that the day of aeroplanes is nearly over.  The
construction of the giant airships of to-day and the successful
return flight of R34 across the Atlantic seem to point to the
eventual triumph, in spite of its disadvantages, of the dirigible
airship. 

This is a hard saying for such of the aeroplane industry as
survived the War period and consolidated itself, and it is but
the saying of a section which bases its belief on the fact that,
as was noted in the very early years of the century, the
aeroplane is primarily a war machine.  Moreover, the experience
of the War period tended to discredit the dirigible, since,
before the introduction of helium gas, the inflammability of its
buoyant factor placed it at an immense disadvantage beside the
machine dependent on the atmosphere itself for its lift.

As life runs to-day, it is a long time since Kipling wrote his
story of the airways of a future world and thrust out a prophecy
that the bulk of the world's air traffic would be carried by
gas-bag vessels.  If the school which inclines to belief in the
dirigible is right in its belief, as it well may be, then the
foresight was uncannily correct, not only in the matter of the
main assumption, but in the detail with which the writer
embroidered it.

On the constructional side, the history of the aeroplane is
still so much in the making that any attempt at a critical
history would be unwise, and it is possible only to record fact,
leaving it to the future for judgment to be passed.  But, in a
general way, criticism may be advanced with regard to the place
that aeronautics takes in civilisation.  In the past hundred
years, the world has made miraculously rapid strides materially,
but moral development has not kept abreast.  Conception of the
responsibilities of humanity remains virtually in a position of
a hundred years ago; given a higher conception of life and its
responsibilities, the aeroplane becomes the crowning achievement
of that long series which James Watt inaugurated, the last step
in intercommunication, the chain with which all nations are
bound in a growing prosperity, surely based on moral wellbeing. 
Without such conception of the duties as well as the rights of
life, this last achievement of science may yet prove the weapon
that shall end civilisation as men know it to-day, and bring
this ultra-material age to a phase of ruin on which saner people
can build a world more reasonable and less given to groping
after purely material advancement.



PART II
   
1903-1920:  PROGRESS IN DESIGN
BY LIEUT.-COL. W. LOCKWOOD MARSH

I. THE  BEGINNINGS

Although the first actual flight of an aeroplane was made by the
Wrights on December 17th 1903, it is necessary, in considering
the progress of design between that period and the present day,
to go back to the earlier days of their experiments with
'gliders,' which show the alterations in design made by them in
their step-bystep progress to a flying machine proper, and give
a clear idea of the stage at which they had arrived in the art
of aeroplane design at the time of their first flights.

They started by carefully surveying the work of previous
experimenters, such as Lilienthal and Chanute, and from the
lesson of some of the failures of these pioneers evolved certain
new principles which were embodied in their first glider, built
in 1900.  In the first place, instead of relying upon the
shifting of the operator's body to obtain balance, which had
proved too slow to be reliable, they fitted in front of the main
supporting surfaces what we now call an 'elevator,' which could
be flexed, to control the longitudinal balance, from where the
operator lay prone upon the main supporting surfaces.  The second
main innovation which they incorporated in this first glider, and
the principle of which is still used in every aeroplane in
existence, was the attainment of lateral balance by warping the
extremities of the main planes.  The effect of warping or pulling
down the extremity of the wing on one side was to increase its
lift and so cause that side to rise.  In the first two gliders
this control was also used for steering to right and left.  Both
these methods of control were novel for other than model work, as
previous experimenters, such as Lilienthal and Pilcher, had
relied entirely upon moving the legs or shifting the position of
the body to control the longitudinal and lateral motions of their
gliders.  For the main supporting surfaces of the glider the
biplane system of Chanute's gliders was adopted with certain
modifications, while the curve of the wings was founded upon the
calculations of Lilienthal as to wind pressure and consequent
lift of the plane.

This first glider was tested on the Kill Devil Hill sand-hills
in North Carolina in the summer of 1900 and proved at any
rate the correctness of the principles of the front elevator and
warping wings, though its designers were puzzled by the fact
that the lift was less than they expected; whilst the 'drag'(as
we call it), or resistance, was also considerably lower than
their predictions.  The 1901 machine was, in consequence, nearly
doubled in area--the lifting surface being increased from 165 to
308 square feet--the first trial taking place on July 27th,
1901, again at Kill Devil Hill.  It immediately appeared that
something was wrong, as the machine dived straight to the
ground, and it was only after the operator's position had been
moved nearly a foot back from what had been calculated as the
correct position that the machine would glide--and even then the
elevator had to be used far more strongly than in the previous
year's glider.  After a good deal of thought the apparent
solution of the trouble was finally found. 

This consisted in the fact that with curved surfaces, while at
large angles the centre of pressure moves forward as the angle
decreases, when a certain limit of angle is reached it travels
suddenly backwards and causes the machine to dive.  The Wrights
had known of this tendency from Lilienthal's researches, but had
imagined that the phenomenon would disappear if they used a
fairly lightly cambered--or curved--surface with a very abrupt
curve at the front.  Having discovered what appeared to be the
cause they surmounted the difficulty by 'trussing down' the
camber of the wings, with the result that they at once got back
to the old conditions of the previous year and could control the
machine readily with small movements of the elevator, even being
able to follow undulations in the ground.  They still found,
however, that the lift was not as great as it should have been;
while the drag remained, as in the previous glider, surprisingly
small.  This threw doubt on previous figures as to wind
resistance and pressure on curved surfaces; but at the same time
confirmed (and this was a most important result) Lilienthal's
previously questioned theory that at small angles the pressure
on a curved surface instead of being normal, or at right angles
to, the chord is in fact inclined in front of the perpendicular. 
The result of this is that the pressure actually tends to draw
the machine forward into the wind--hence the small amount of
drag, which had puzzled Wilbur and Orville Wright.

Another lesson which was learnt from these first two years of
experiment, was that where, as in a biplane, two surfaces are
superposed one above the other, each of them has somewhat less
lift than it would have if used alone.  The experimenters were
also still in doubt as to the efficiency of the warping method
of controlling the lateral balance as it gave rise to certain
phenomena which puzzled them, the machine turning towards the
wing having the greater angle, which seemed also to touch the
ground first, contrary to their expectations.  Accordingly, on
returning to Dayton towards the end of 1901, they set
themselves to solve the various problems which had appeared and
started on a lengthy series of experiments to check the previous
figures as to wind resistance and lift of curved surfaces,
besides setting themselves to grapple with the difficulty of
lateral control.  They accordingly constructed for themselves at
their home in Dayton a wind tunnel 16 inches square by 6 feet
long in which they measured the lift and 'drag' of more than two
hundred miniature wings.  In the course of these tests they for
the first time produced comparative results of the lift of
oblong and square surfaces, with the result that they
re-discovered the importance of 'aspect ratio'--the ratio of
length to breadth of planes.  As a result, in the next year's
glider the aspect ration of the wings was increased from the
three to one of the earliest model to about six to one, which is
approximately the same as that used in the machines of to-day. 
Further than that, they discussed the question of lateral
stability, and came to the conclusion that the cause of the
trouble was that the effect of warping down one wing was to
increase the resistance of, and consequently slow down, that
wing to such an extent that its lift was reduced sufficiently to
wipe out the anticipated increase in lift resulting from the
warping. From this they deduced that if the speed of the warped
wing could be controlled the advantage of increasing the angle
by warping could be utilised as they originally intended.  They
therefore decided to fit a vertical fin at the rear which, if the
machine attempted to turn, would be exposed more and more to the
wind and so stop the turning motion by offering increased
resistance.

As a result of this laboratory research work the third Wright
glider, which was taken to Kill Devil Hill in September, 1902,
was far more efficient aerodynamically than either of its two
predecessors, and was fitted with a fixed vertical fin at the
rear in addition to the movable elevator in front.  According to
Mr Griffith Brewer,[*] this third glider contained 305 square
feet of surface; though there may possibly be a mistake here, as
he states[**] the surface of the previous year's glider to have
been only 290 square feet, whereas Wilbur Wright himself[***]
states it to have been 308 square feet.  The matter is not,
perhaps, save historically, of much importance, except that the
gliders are believed to have been progressively larger, and
therefore if we accept Wilbur Wright's own figure of the surface
of the second glider, the third must have had a greater area
than that given by Mr Griffith Brewer.  Unfortunately, no
evidence of the Wright Brothers themselves on this point is
available.

[*] Fourth Wilbur Wright Memorial Lecture, Aeronautical Journal,
Vol. XX, No. 79, page 75.

[**] Ibid. page 73.  

[***] Ibid.  pp. 91 and 102.

The first glide of the 1902, season was made on September 17th
of that year, and the new machine at once showed itself an
improvement on its predecessors, though subsequent trials showed
that the difficulty of lateral balance had not been entirely
overcome.  It was decided, therefore, to turn the vertical fin
at the rear into a rudder by making it movable.  At the same
time it was realised that there was a definite relation between
lateral balance and directional control, and the rudder controls
and wing-warping wires were accordingly connected This ended the
pioneer gliding experiments of Wilbur and Orville Wright--though
further glides were made in subsequent years--as the following
year, 1903, saw the first power-driven machine leave the ground.

To recapitulate--in the course of these original experiments the
Wrights confirmed Lilienthal's theory of the reversal of the
centre of pressure on cambered surfaces at small angles of
incidence:  they confirmed the importance of high aspect ratio
in respect to lift:  they had evolved new and more accurate
tables of lift and pressure on cambered surfaces:  they were the
first to use a movable horizontal elevator for controlling
height:  they were the first to adjust the wings to different
angles of incidence to maintain lateral balance:  and they were
the first to use the movable rudder and adjustable wings in
combination.

They now considered that they had gone far enough to justify
them in building a power-driven 'flier,' as they called their
first aeroplane.  They could find no suitable engine and so
proceeded to build for themselves an internal combustion engine,
which was designed to give 8 horse-power, but when completed
actually developed about 12-15 horse-power and weighed 240 lbs. 
The complete machine weighed about 750 lbs.  Further details of
the first Wright aeroplane are difficult to obtain, and even
those here given should be received with some caution.  The
first flight was made on December 17th 1903, and lasted 12
seconds.  Others followed immediately, and the fourth lasted 59
seconds, a distance of 852 feet being covered against a 20-mile
wind.

The following year they transferred operations to a field
outside Dayton, Ohio (their home), and there they flew a
somewhat larger and heavier machine with which on September 20th
1904, they completed the first circle in the air.  In this
machine for the first time the pilot had a seat; all the
previous experiments having been carried out with the operator
lying prone on the lower wing.  This was followed next year by
another still larger machine, and on it they carried out many
flights.  During the course of these flights they satisfied
themselves as to the cause of a phenomenon which had puzzled
them during the previous year and caused them to fear that they
had not solved the problem of lateral control.  They found that
on occasions--always when on a turn--the machine began to slide
down towards the ground and that no amount of warping could stop
it.  Finally it was found that if the nose of the machine was
tilted down a recovery could be effected; from which they
concluded that what actually happened was that the machine,
'owing to the increased load caused by centrifugal force,' had
insufficient power to maintain itself in the air and therefore
lost speed until a point was reached at which the controls
became inoperative.  In other words, this was the first
experience of 'stalling on a turn,' which is a danger against
which all embryo pilots have to guard in the early stages of
their training.

The 1905 machine was, like its predecessors, a biplane with a
biplane elevator in front and a double vertical rudder in rear. 
The span was 40 feet, the chord of the wings being 6 feet and
the gap between them about the same.  The total area was about
600 square feet which supported a total weight of 925 lbs.;
while the motor was 12 to 15 horse-power driving two propellers
on each side behind the main planes through chains and giving
the machine a speed of about 30 m.p.h. one of these chains was
crossed so that the propellers revolved in opposite directions
to avoid the torque which it was feared would be set up if they
both revolved the same way.  The machine was not fitted with a
wheeled undercarriage but was carried on two skids, which also
acted as outriggers to carry the elevator.  Consequently, a
mechanical method of launching had to be evolved and the machine
received initial velocity from a rail, along which it was drawn
by the impetus provided by the falling of a weight from a wooden
tower or 'pylon.'  As a result of this the Wright aeroplane in
its original form had to be taken back to its starting rail
after each flight, and could not restart from the point of
alighting.  Perhaps, in comparison with French machines of more
or less contemporary date (evolved on independent lines in
ignorance of the Americans' work), the chief feature of the
Wright biplane of 1905 was that it relied entirely upon the
skill of the operator for its stability; whereas in France some
attempt was being made, although perhaps not very successfully,
to make the machine automatically stable laterally.  The
performance of the Wrights in carrying a loading of some 60 lbs. 
per horse-power is one which should not be overlooked.  The wing
loading was about 1 1/2 lbs.  per square foot.

About the same time that the Wrights were carrying out their
power-driven experiments, a band of pioneers was quite
independently beginning to approach success in France.  In
practically every case, however, they started from a somewhat
different standpoint and took as their basic idea the cellular
(or box) kite.  This form of kite, consisting of two superposed
surfaces connected at each end by a vertical panel or curtain of
fabric, had proved extremely successful for man-carrying
purposes, and, therefore, it was little wonder that several minds
conceived the idea of attempting to fly by fitting a series of
box-kites with an engine.  The first to achieve success was M.
Santos-Dumont, the famous Brazilian pioneer-designer of airships,
who, on November 12th, 1906, made several flights, the last of
which covered a little over 700 feet.  Santos-Dumont's machine
consisted essentially of two box-kites, forming the main wings,
one on each side of the body, in which the pilot stood, and at
the front extremity of which was another movable box-kite to act
as elevator and rudder.  The curtains at the ends were intended
to give lateral stability, which was further ensured by setting
the wings slightly inclined upwards from the centre, so that when
seen from the front they formed a wide V.  This feature is still
to be found in many aeroplanes to-day and has come to be known
as the 'dihedral.'  The motor was at first of 24 horse-power, for
which later a 50 horse-power Antoinette engine was substituted;
whilst a three-wheeled undercarriage was provided, so that the
machine could start without external mechanical aid.  The
machine was constructed of bamboo and steel, the weight being as
low as 352 lbs.  The span was 40 feet, the length being 33 feet,
with a total surface of main planes of 860 square feet.  It will
thus be seen--for comparison with the Wright machine--that the
weight per horse-power (with the 50 horse-power engine) was only
7 lbs., while the wing loading was equally low at 1/2 lb. per
square foot.

The main features of the Santos-Dumont machine were the box-kite
form of construction, with a dihedral angle on the main planes,
and the forward elevator which could be moved in any direction
and therefore acted in the same way as the rudder at the rear of
the Wright biplane.  It had a single propeller revolving in the
centre behind the wings and was fitted with an undercarriage
incorporated in the machine.

The other chief French experimenters at this period were the
Voisin Freres, whose first two machines--identical in
form--were sold to Delagrange and H. Farman, which has sometimes
caused confusion, the two purchasers being credited with the
design they bought.  The Voisins, like the Wrights, based their
designs largely on the experimental work of Lilienthal, Langley,
Chanute, and others, though they also carried out tests on the
lifting properties of aerofoils in a wind tunnel of their own.
Their first machines, like those of Santos-Dumont, showed the
effects of experimenting with box-kites, some of which they had
built for M. Ernest Archdeacon in 1904.  In their case the
machine, which was again a biplane, had, like both the others
previously mentioned, an elevator in front--though in this case
of monoplane form--and, as in the Wright, a rudder was fitted in
rear of the main planes. The Voisins, however, fitted a fixed
biplane horizontal 'tail'--in an effort to obtain a measure of
automatic longitudinal stability--between the two surfaces of
which the single rudder worked.  For lateral stability they
depended entirely on end curtains between the upper and lower
surfaces of both the main planes and biplane tail surfaces. 
They, like Santos-Dumont, fitted a wheeled undercarriage, so
that the machine was self-contained. The Voisin machine, then,
was intended to be automatically stable in both senses; whereas
the Wrights deliberately produced a machine which was entirely
dependent upon the pilot's skill for its stability.  The
dimensions of the Voisin may be given for comparative purposes,
and were as follows:  Span 33 feet with a chord (width from back
to front) of main planes of 6 1/2 feet, giving a total area of
430 square feet.  The 50 horse-power Antoinette engine, which was
enclosed in the body (or 'nacelle ') in the front of which the
pilot sat, drove a propeller behind, revolving between the
outriggers carrying the tail.  The total weight, including Farman
as pilot, is given as 1,540 lbs., so that the machine was much
heavier than either of the others; the weight per horse-power
being midway between the Santos-Dumont and the Wright at 31 lbs. 
per square foot, while the wing loading was considerably greater
than either at 3 1/2 lbs. per square foot.  The Voisin machine
was
experimented with by Farman and Delagrange from about June 1907
onwards, and was in the subsequent years developed by Farman; and
right up to the commencement of the War upheld the principles of
the box-kite method of construction for training purposes.  The
chief modification of the original design was the addition of
flaps (or ailerons) at the rear extremities of the main planes to
give lateral control, in a manner analogous to the wing-warping
method invented by the Wrights, as a result of which the end
curtains between the planes were abolished.  An additional
elevator was fitted at the rear of the fixed biplane tail, which
eventually led to the discarding of the front elevator
altogether.  During the same period the Wright machine came into
line with the others by the fitting of a wheeled undercarriage
integral with the machine.  A fixed horizontal tail was also
added to the rear rudder, to which a movable elevator was later
attached; and, finally, the front elevator was done away with. 
It will thus be seen that having started from the very different
standpoints of automatic stability and complete control by the
pilot, the Voisin (as developed in the Farman) and Wright
machines, through gradual evolution finally resulted in
aeroplanes of similar characteristics embodying a modicum of
both features.

Before proceeding to the next stage of progress mention should
be made of the experimental work of Captain Ferber in France. 
This officer carried out a large number of experiments with
gliders contemporarily with the Wrights, adopting--like
them--the Chanute biplane principle.  He adopted the front
elevator from the Wrights, but immediately went a step farther
by also fitting a fixed tail in rear, which did not become a
feature of the Wright machine until some seven or eight years
later.  He built and appeared to have flown a machine fitted
with a motor in 1905, and was commissioned to go to America by
the French War Office on a secret mission to the Wrights.
Unfortunately, no complete account of his experiments appears to
exist, though it can be said that his work was at least as
important as that of any of the other pioneers mentioned.



II. MULTIPLICITY OF IDEAS

In a review of progress such as this, it is obviously
impossible, when a certain stage of development has been
reached, owing to the very multiplicity of experimenters, to
continue dealing in anything approaching detail with all the
different types of machines; and it is proposed, therefore, from
this point to deal only with tendencies, and to mention
individuals merely as examples of a class of thought rather than
as personalities, as it is often difficult fairly to allocate
the responsibility for any particular innovation.

During 1907 and 1908 a new type of machine, in the monoplane,
began to appear from the workshops of Louis Bleriot, Robert
Esnault-Pelterie, and others, which was destined to give rise to
long and bitter controversies on the relative advantages of the
two types, into which it is not proposed to enter here; though
the rumblings of the conflict are still to be heard by
discerning ears.  Bleriot's early monoplanes had certain new
features, such as the location of the pilot, and in some cases
the engine, below the wing; but in general his monoplanes,
particularly the famous No. XI on which the first Channel
crossing was made on July 25th, 1909, embodied the main
principles of the Wright and Voisin types, except that the
propeller was in front of instead of behind the supporting
surfaces, and was, therefore, what is called a 'tractor' in
place of the then more conventional 'pusher.'  Bleriot aimed at
lateral balance by having the tip of each wing pivoted, though he
soon fell into line with the Wrights and adopted the warping
system.  The main features of the design of Esnault-Pelterie's
monoplane was the inverted dihedral (or kathedral as this was
called in Mr S. F. Cody's British Army Biplane of 1907) on the
wings, whereby the tips were considerably lower than the roots at
the body.  This was designed to give automatic lateral stability,
but, here again, conventional practice was soon adopted and the
R.E.P. monoplanes, which became well-known in this country
through their adoption in the early days by Messrs Vickers, were
of the ordinary monoplane design, consisting of a tractor
propeller with wire-stayed wings, the pilot being in an enclosed
fuselage containing the engine in front and carrying at its rear
extremity fixed horizontal and vertical surfaces combined with
movable elevators and rudder.  Constructionally, the R.E.P.
monoplane was of extreme interest as the body was constructed of
steel.  The Antoinette monoplane, so ably flown by Latham, was
another very famous machine of the 1909-1910 period, though its
performance were frequently marred by engine failure; which was
indeed the bugbear of all these early experimenters, and it is
difficult to say, after this lapse of time, how far in many cases
the failures which occurred, both in performances and even in the
actual ability to rise from the ground, were due to defects in
design or merely faults in the primitive engines available.  The
Antoinette aroused admiration chiefly through its graceful,
birdlike lines, which have probably never been equalled; but its
chief interest for our present purpose lies in the novel method
of wing-staying which was employed.  Contemporary monoplanes
practically all had their  wings stayed by wires to a post in the
centre above the fuselage, and, usually, to the undercarriage
below.  In the Antoinette, however, a king post was introduced
half-way along the wing, from which wires were carried to the
ends of the wings and the body.  This was intended to give
increased strength and permitted of a greater wing-spread and
consequently improved aspect ratio.  The same system of
construction was adopted in the British Martinsyde monoplanes of
two or three years later.

This period also saw the production of the first triplane, which
was built by A. V. Roe in England and was fitted with a J.A.P. 
engine of only 9 horse-power--an amazing performance which
remains to this day unequalled.  Mr Roe's triplane was chiefly
interesting otherwise for the method of maintaining longitudinal
control, which was achieved by pivoting the whole of the three
main planes so that their angle of incidence could be altered. 
This was the direct converse of the universal practice of
elevating by means of a subsidiary surface either in front or
rear of the main planes.

Recollection of the various flying meetings and exhibitions
which one attended during the years from 1909 to 1911, or even
1912 are chiefly notable for the fact that the first thought on
seeing any new type of machine was not as to what its
'performance'--in speed, lift, or what not--would be; but
speculation as to whether it would leave the ground at all when
eventually tried.  This is perhaps the best indication of the
outstanding characteristic of that interim period between the
time of the first actual flights and the later period,
commencing about 1912, when ideas had become settled and it
was at last becoming possible to forecast on the drawing-board
the performance of the completed machine in the air.  Without
going into details, for which there is no space here, it is
difficult to convey the correct impression of the chaotic state
which existed as to even the elementary principles of aeroplane
design.  All the exhibitions contained large numbers--one had
almost written a majority--of machines which embodied the most
unusual features and which never could, and in practice never
did, leave the ground.  At the same time, there were few who
were sufficiently hardy to say certainly that this or that
innovation was wrong; and consequently dozens of inventors in
every country were conducting isolated experiments on both good
and bad lines.  All kinds of devices, mechanical and otherwise,
were claimed as the solution of the problem of stability, and
there was even controversy as to whether any measure of
stability was not undesirable; one school maintaining that the
only safety lay in the pilot having the sole say in the attitude
of the machine at any given moment, and fearing danger from the
machine having any mind of its own, so to speak.  There was, as
in most controversies, some right on both sides, and when we
come to consider the more settled period from 1912 to the
outbreak of the War in 1914 we shall find how a compromise was
gradually effected.

At the same time, however, though it was at the time difficult
to pick out, there was very real progress being made, and,
though a number of 'freak' machines fell out by the wayside, the
pioneer designers of those days learnt by a process of trial and
error the right principles to follow and gradually succeeded in
getting their ideas crystallised.

In connection with stability mention must be made of a machine
which was evolved in the utmost secrecy by Mr J. W. Dunne in a
remote part of Scotland under subsidy from the War office.  This
type, which was constructed in both monoplane and biplane form,
showed that it was in fact possible in 1910 and 1911 to design an
aeroplane which could definitely be left to fly itself in the
air.  One of the Dunne machines was, for example flown from
Farnborough to Salisbury Plain without any control other than the
rudder being touched; and on another occasion it flew a complete
circle with all controls locked automatically assuming the
correct bank for the radius of turn.  The peculiar form of wing
used, the camber of which varied from the root to the tip, gave
rise however, to a certain loss in efficiency, and there was also
a difficulty in the pilot assuming adequate control when desired.
Other machines designed to be stable--such as the German Etrich
and the British Weiss gliders and Handley-Page monoplanes--were
based on the analogy of a wing attached to a certain seed found
in Nature (the 'Zanonia' leaf), on the righting effect of
back-sloped wings combined with upturned (or 'negative') tips. 
Generally speaking, however, the machines of the 1909-1912 period
relied for what automatic stability they had on the principle of
the dihedral angle, or flat V, both longitudinally and laterally.
Longitudinally this was obtained by setting the tail at a
slightly smaller angle than the main planes.

The question of reducing the resistance by adopting 'stream-line'
forms, along which the air could flow uninterruptedly without the
formation of eddies, was not at first properly realised, though
credit should be given to Edouard Nieuport, who in 1909 produced
a monoplane with a very large body which almost completely
enclosed the pilot and made the machine very fast, for those
days, with low horse-power.  On one of these machines C. T.
Weyman won the Gordon-Bennett Cup for America in 1911 and
another put up a fine performance in the same race with only a 30
horse-power engine.  The subject, was however, early taken up by
the British Advisory Committee for Aeronautics, which was
established by the Government in 1909, and designers began to
realise the importance of streamline struts and fuselages towards
the end of this transition period.  These efforts were at first
not always successful and showed at times a lack of understanding
of the problems involved, but there was a very marked improvement
during the year 1912.  At the Paris Aero Salon held early in that
year there was a notable variety of ideas on the subject; whereas
by the time of the one held in October designs had considerably
settled down, more than one exhibitor showing what were called
'monocoque' fuselages completely circular in shape and having
very low resistance, while the same show saw the introduction of
rotating cowls over the propeller bosses, or 'spinners,' as they
came to be called during the War.  A particularly fine example of
stream-lining was to be found in the Deperdussin monoplane on
which Vedrines won back the Gordon-Bennett Aviation Cup from
America at a speed of 105.5 m.p.h.--a considerable improvement on
the 78 m.p.h. of the preceding year, which was by no means
accounted for by the mere increase in engine power from 100
horse-power to 140 horse-power.  This machine was the first in
which the refinement of 'stream-lining' the pilot's head, which
became a feature of subsequent racing machines, was introduced. 
This consisted of a circular padded excresence above the cockpit
immediately behind the pilot's head, which gradually tapered off
into the top surface of the fuselage.  The object was to give the
air an uninterrupted flow instead of allowing it to be broken up
into eddies behind the head of the pilot, and it also provided a
support against the enormous wind-pressure encountered.  This
true stream-line form of fuselage owed its introduction to the
Paulhan-Tatin 'Torpille' monoplane of the Paris Salon of early
1917.  Altogether the end of the year 1912 began to see the
disappearance of 'freak' machines with all sorts of original
ideas for the increase of stability and performance.  Designs had
by then gradually become to a considerable extent standardised,
and it had become unusual to find a machine built which would
fail to fly.  The Gnome engine held the field owing to its
advantages, as the first of the rotary type, in lightness and
ease of fitting into the nose of a fuselage.  The majority of
machines were tractors (propeller in front) although a
preference, which died down subsequently, was still shown for the
monoplane over the biplane.  This year also saw a great increase
in the number of seaplanes, although the 'flying boat' type had
only appeared at intervals and the vast majority were of the
ordinary aeroplane type fitted with floats in place of the land
undercarriage; which type was at that time commonly called
'hydro-aeroplane.'  The usual horse power was 50--that of the
smallest Gnome engine--although engines of 100 to 140 horse-power
were also fitted occasionally.  The average weight per
horse-power varied from 18 to 25 lbs., while the wing-loading was
usually in the neighbourhood of 5 to 6 lbs. per square foot.  The
average speed ranged from 65-75 miles per hour.



III. PROGRESS ON STANDARDISED LINES

In the last section an attempt has been made to show how, during
what was from the design standpoint perhaps the most critical
period, order gradually became evident out of chaos,
ill-considered ideas dropped out through failure to make good,
and, though there was still plenty of room for improvement in
details, the bulk of the aeroplanes showed a general similarity
in form and conception.  There was still a great deal to be
learnt in finding the best form of wing section, and performances
were still low; but it had become definitely possible to say that
flying had emerged from the chrysalis stage and had become a
science.  The period which now began was one of scientific
development and improvement--in performance, manoeuvrability,
and general airworthiness and stability.

The British Military Aeroplane Competition held in the summer of
1912 had done much to show the requirements in design by giving
possibly the first opportunity for a definite comparison of the
performance of different machines as measured by impartial
observers on standard lines--albeit the methods of measuring were
crude.  These showed that a high speed--for those days--of 75
miles an hour or so was attended by disadvantages in the form of
an equally fast low speed, of 50 miles per hour or more, and
generally may be said to have given designers an idea what to aim
for and in what direction improvements were required.  In fact,
the most noticeable point perhaps of the machines of this time
was the marked manner in which a machine that was good in one
respect would be found to be wanting in others.  It had not yet
been possible to combine several desirable attributes in one
machine.   The nearest approach to this was perhaps to be found
in the much discussed Government B.E.2 machine, which was
produced from the Royal Aircraft Factory at Farnborough, in the
summer of 1912.  Though considerably criticized from many points
of view it was perhaps the nearest approach to a machine of
all-round efficiency that had up to that date appeared.  The
climbing rate, which subsequently proved so important for
military purposes, was still low, seldom, if ever, exceeding 400
feet per minute; while gliding angles (ratio of descent to
forward travel over the ground with engine stopped) little
exceeded 1 in 8.

The year 1912 and 1913 saw the subsequently all-conquering
tractor biplane begin to come into its own.  This type, which
probably originated in England, and at any rate attained to its
greatest excellence prior to the War from the drawing offices of
the Avro Bristol and Sopwith firms, dealt a blow at the monoplane
from which the latter never recovered. 

The two-seater tractor biplane produced by Sopwith and piloted
by H. G. Hawker, showed that it was possible to produce a
biplane with at least equal speed to the best monoplanes, whilst
having the advantage of greater strength and lower landing
speeds.  The Sopwith machine had a top speed of over 80 miles an
hour while landing as slowly as little more than 30 miles an
hour; and also proved that it was possible to carry 3 passengers
with fuel for 4 hours' flight with a motive power of only 80
horse-power.  This increase in efficiency was due to careful
attention to detail in every part, improved wing sections, clean
fuselage-lines, and simplified undercarriages.  At the same
time, in the early part of 1913 a tendency manifested itself
towards the four-wheeled undercarriage, a pair of smaller wheels
being added in front of the main wheels to prevent overturning
while running on the ground; and several designs of
oleo-pneumatic and steel-spring undercarriages were produced in
place of the rubber shock-absorber type which had up till then
been almost universal.

These two statements as to undercarriage designs may appear to
be contradictory, but in reality they do not conflict as they
both showed a greater attention to the importance of good
springing, combined with a desire to avoid complication and a
mass of struts and wires which increased head resistance.

The Olympia Aero Show of March, 1913, also produced a machine
which, although the type was not destined to prove the best for
the purpose for which it was designed, was of interest as being
the first to be designed specially for war purposes.  This was
the Vickers 'Gun-bus,' a 'pusher' machine, with the propeller
revolving behind the main planes between the outriggers carrying
the tail, with a seat right in front for a gunner who was
provided with a machine gun on a swivelling mount which had a
free field of fire in every direction forward.  The device which
proved the death-blow for this type of aircraft during the war
will be dealt with in the appropriate place later, but the
machine should not go unrecorded.

As a result of a number of accidents to monoplanes the
Government appointed a Committee at the end of 1912 to inquire
into the causes of these.  The report which was presented in
March, 1913, exonerated the monoplane by coming to the
conclusion that the accidents were not caused by conditions
peculiar to monoplanes, but pointed out certain desiderata in
aeroplane design generally which are worth recording.  They
recommended that the wings of aeroplanes should be so internally
braced as to have sufficient strength in themselves not to
collapse if the external bracing wires should give way.  The
practice, more common in monoplanes than biplanes, of carrying
important bracing wires from the wings to the undercarriage was
condemned owing to the liability of damage from frequent
landings.  They also pointed out the desirability of duplicating
all main wires and their attachments, and of using stranded
cable for control wires.  Owing to the suspicion that one
accident at least had been caused through the tearing of the
fabric away from the wing, it was recommended that fabric should
be more securely fastened to the ribs of the wings, and that
devices for preventing the spreading of tears should be
considered.  In the last connection it is interesting to note
that the French Deperdussin firm produced a fabric wing-covering
with extra strong threads run at right-angles through the fabric
at intervals in order to limit the tearing to a defined area.

In spite, however, of the whitewashing of the monoplane by the
Government Committee just mentioned, considerable stir was
occasioned later in the year by the decision of the War office
not to order any more monoplanes; and from this time forward
until the War period the British Army was provided exclusively
with biplanes.  Even prior to this the popularity of the
monoplane had begun to wane.  At the Olympia Aero Show in March,
1913, biplanes for the first time outnumbered the
'single-deckers'(as the Germans call monoplanes); which had the
effect of reducing the wing-loading.  In the case of the
biplanes exhibited this averaged about 4 1/2 lbs. per square
foot, while in the case of the monoplanes in the same exhibition
the lowest was 5 1/2 lbs., and the highest over 8 1/2 lbs. per
square foot of area.  It may here be mentioned that it was not
until the War period that the importance of loading per
horse-power was recognised as the true criterion of aeroplane
efficiency, far greater interest being displayed in the amount
of weight borne per unit area of wing.

An idea of the state of development arrived at about this time
may be gained from the fact that the Commandant of the Military
Wing of the Royal Flying Corps in a lecture before the Royal
Aeronautical Society read in February, 1913, asked for
single-seater scout aeroplanes with a speed of 90 miles an hour
and a landing speed of 45 miles an hour--a performance which
even two years later would have been considered modest in the
extreme.  It serves to show that, although higher performances
were put up by individual machines on occasion, the general
development had not yet reached the stage when such performances
could be obtained in machines suitable for military purposes. 
So far as seaplanes were concerned, up to the beginning of 1913
little attempt had been made to study the novel problems
involved, and the bulk of the machines at the Monaco Meeting in
April, 1913, for instance, consisted of land machines fitted with
floats, in many cases of a most primitive nature, without other
alterations.  Most of those which succeeded in leaving the water
did so through sheer pull of engine power; while practically all
were incapable of getting off except in a fair sea, which enabled
the pilot to jump the machine into the air across the trough
between two waves.  Stability problems had not yet been
considered, and in only one or two cases was fin area added at
the rear high up, to counterbalance the effect of the floats low
down in front.  Both twin and single-float machines were used,
while the flying boat was only just beginning to come into being
from the workshops of Sopwith in Great Britain, Borel-Denhaut in
France, and Curtiss in America.  In view of the approaching
importance of amphibious seaplanes, mention should be made of the
flying boat (or 'bat boat' as it was called, following Rudyard
Kipling) which was built by Sopwith in 1913 with a wheeled
landing-carriage which could be wound up above the bottom surface
of the boat so as to be out of the way when alighting on water.

During 1913 the (at one time almost universal) practice
originated by the Wright Brothers, of warping the wings for
lateral stability, began to die out and the bulk of aeroplanes
began to be fitted with flaps (or 'ailerons') instead.  This
was a distinct change for the better, as continually warping the
wings by bending down the extremities of the rear spars was
bound in time to produce 'fatigue' in that member and lead to
breakage; and the practice became completely obsolete during the
next two or three years.

The Gordon-Bennett race of September, 1913, was again won by
a Deperdussin machine, somewhat similar to that of the previous
year, but with exceedingly small wings, only 107 square feet in
area.  The shape of these wings was instructive as showing how
what, from the general utility point of view, may be
disadvantageous can, for a special purpose, be turned to
account.  With a span of 21 feet, the chord was 5 feet, giving
the inefficient 'aspect ratio' of slightly over 4 to 1 only. 
The object of this was to reduce the lift, and therefore the
resistance, to as low a point as possible.  The total weight was
1,500 lbs., giving a wing-loading of 14 lbs. per square foot--a
hitherto undreamt-of figure.  The result was that the machine
took an enormously long run before starting; and after touching
the ground on landing ran for nearly a mile before stopping; but
she beat all records by attaining a speed of 126 miles per
hour.  Where this performance is mainly interesting is in
contrast to the machines of 1920, which with an even higher
speed capacity would yet be able to land at not more than 40 or
50 miles per hour, and would be thoroughly efficient flying
machines.

The Rheims Aviation Meeting, at which the Gordon-Bennett race
was flown, also saw the first appearance of the Morane 'Parasol'
monoplane.  The Morane monoplane had been for some time an
interesting machine as being the only type which had no fixed
surface in rear to give automatic stability, the movable
elevator being balanced through being hinged about one-third of
the way back from the front edge.  This made the machine
difficult to fly except in the hands of experts, but it was very
quick and handy on the controls and therefore useful for racing
purposes.  In the 'Parasol' the modification was introduced of
raising the wing above the body, the pilot looking out beneath
it, in order to give as good a view as possible.

Before passing to the year 1914 mention should be made of the
feat performed by Nesteroff, a Russian, and Pegoud, a French
pilot, who were the first to demonstrate the possibilities of
flying upside-down and looping the loop.  Though perhaps not
coming strictly within the purview of a chapter on design
(though certain alterations were made to the top wing-bracing of
the machine for this purpose) this performance was of extreme
importance to the development of aviation by showing the
possibility of recovering, given reasonable height, from any
position in the air; which led designers to consider the extra
stresses to which an aeroplane might be subjected and to take
steps to provide for them by increasing strength where
necessary.

When the year 1914 opened a speed of 126 miles per hour had been
attained and a height of 19,600 feet had been reached.  The
Sopwith and Avro (the forerunner of the famous training machine
of the War period) were probably the two leading tractor
biplanes of the world, both two-seaters with a speed variation
from 40 miles per hour up to some 90 miles per hour with 80
horse-power engines.  The French were still pinning their faith
mainly to monoplanes, while the Germans were beginning to come
into prominence with both monoplanes and biplanes of the 'Taube'
type.  These had wings swept backward and also upturned at the
wing-tips which, though it gave a certain measure of automatic
stability, rendered the machine somewhat clumsy in the air, and
their performances were not on the whole as high as those of
either France or Great Britain.

Early in 1914 it became known that the experimental work of
Edward Busk--who was so lamentably killed during an experimental
flight later in the year--following upon the researches of
Bairstow and others had resulted in the production at the Royal
Aircraft Factory at Farnborough of a truly automatically stable
aeroplane. This was the 'R.E.' (Reconnaissance Experimental), a
development of the B.E. which has already been referred to.  The
remarkable feature of this design was that there was no
particular device to which one could point out as the cause of
the stability.  The stable result was attained simply by detailed
design of each part of the aeroplane, with due regard to its
relation to, and effect on, other parts in the air.  Weights and
areas were so nicely arranged that under practically any
conditions the machine tended to right itself.  It did not,
therefore, claim to be a machine which it was impossible to
upset, but one which if left to itself would tend to right itself
from whatever direction a gust might come.  When the principles
were extended to the 'B.E. 2c' type (largely used at the outbreak
of the War) the latter machine, if the engine were switched of f
at a height of not less than 1,000 feet above the ground, would
after a few moments assume its correct gliding angle and glide
down to the ground.

The Paris Aero Salon of December, 1913, had been remarkable
chiefly for the large number of machines of which the chassis and
bodywork had been constructed of steel-tubing; for the excess of
monoplanes over biplanes; and (in the latter) predominance of
'pusher' machines (with propeller in rear of the main planes)
compared with the growing British preference for 'tractors' (with
air screw in front).  Incidentally, the Maurice Farman, the last
relic of the old type box-kite with elevator in front appeared
shorn of this prefix, and became known as the 'short-horn' in
contradistinction to its front-elevatored predecessor which,
owing to its general reliability and easy flying capabilities,
had long been affectionately called the 'mechanical cow.'  The 
1913 Salon also saw some lingering attempts at attaining
automatic stability by pendulum and other freak devices.

Apart from the appearance of 'R.E.1,' perhaps the most notable
development towards the end of 1913 was the appearance of the
Sopwith 'Tabloid 'tractor biplane.  This single-seater machine,
evolved from the two-seater previously referred to, fitted with a
Gnome engine of 80 horse-power, had the, for those days,
remarkable speed of 92 miles an hour; while a still more
notable feature was that it could remain in level flight at not
more than 37 miles per hour.  This machine is of particular
importance because it was the prototype and forerunner of the
successive designs of single-seater scout fighting machines
which were used so extensively from 1914 to 1918.  It was also
probably the first machine to be capable of reaching a height of
1,000 feet within one minute.  It was closely followed by the
'Bristol Bullet,' which was exhibited at the Olympia Aero Show
of March, 1914.  This last pre-war show was mainly remarkable
for the good workmanship displayed--rather than for any distinct
advance in design.  In fact, there was a notable diversity in
the types displayed, but in detailed design considerable
improvements were to be seen, such as the general adoption of
stranded steel cable in place of piano wire for the mail bracing



IV. THE WAR PERIOD

Up to this point an attempt has been made to give some idea of
the progress that was made during the eleven years that had
elapsed since the days of the Wrights' first flights.  Much
advance had been made and aeroplanes had settled down,
superficially at any rate, into more or less standardised forms
in three main types--tractor monoplanes, tractor biplanes, and
pusher biplanes.  Through the application of the results of
experiments with models in wind tunnels to full-scale machines,
considerable improvements had been made in the design of wing
sections, which had greatly increased the efficiency of
aeroplanes by raising the amount of 'lift' obtained from the
wing compared with the 'drag' (or resistance to forward motion)
which the same wing would cause.  In the same way the shape of
bodies, interplane struts, etc., had been improved to be of
better stream-line shape, for the further reduction of
resistance; while the problems of stability were beginning to be
tolerably well understood.  Records (for what they are worth)
stood at 21,000 feet as far as height was concerned, 126 miles
per hour for speed, and 24 hours duration. That there was
considerable room for development is, however, evidenced by a
statement made by the late B. C. Hucks (the famous pilot) in
the course of an address delivered before the Royal Aeronautical
Society in July, 1914.  'I consider,' he said, 'that the present
day standard of flying is due far more to the improvement in
piloting than to the improvement in machines.... I consider
those (early 1914) machines are only slight improvements on the
machines of three years ago, and yet they are put through
evolutions which, at that time, were not even dreamed of.  I can
take a good example of the way improvement in piloting has
outdistanced improvement in machines--in the case of myself, my
'looping' Bleriot.  Most of you know that there is very little
difference between that machine and the 50 horse-power Bleriot
of three years ago.'  This statement was, of course, to some
extent an exaggeration and was by no means agreed with by
designers, but there was at the same time a germ of truth in it. 
There is at any rate little doubt that the theory and practice
of aeroplane design made far greater strides towards becoming an
exact science during the four years of War than it had done
during the six or seven years preceding it.

It is impossible in the space at disposal to treat of this
development even with the meagre amount of detail that has been
possible while covering the 'settling down' period from 1911 to
1914, and it is proposed, therefore, to indicate the improvements
by sketching briefly the more noticeable difference in various
respects between the average machine of 1914 and a similar
machine of 1918.

In the first place, it was soon found that it was possible to
obtain greater efficiency and, in particular, higher speeds,
from tractor machines than from pusher machines with the air
screw behind the main planes.  This was for a variety of reasons
connected with the  efficiency of propellers and the possibility
of reducing resistance to a greater extent in tractor machines
by using a 'stream-line' fuselage (or body) to connect the main
planes with the tail.  Full advantage of this could not be
taken, however, owing to the difficulty of fixing a machine-gun
in a forward direction owing to the presence of the propeller. 
This was finally overcome by an ingenious device (known as an
'Interrupter gear') which allowed the gun to fire only when
none of the propeller blades was passing in front of the muzzle. 
The monoplane gradually fell into desuetude, mainly owing to the
difficulty of making that type adequately strong without it
becoming prohibitively heavy, and also because of its high
landing speed and general lack of manoeuvrability.  The triplane
was also little used except in one or two instances, and,
practically speaking, every machine was of the biplane tractor
type.

A careful consideration of the salient features leading to
maximum efficiency in aeroplanes--particularly in regard to
speed and climb, which were the two most important military
requirements--showed that a vital feature was the reduction in
the amount of weight lifted per horse-power employed; which in
1914 averaged from 20 to 25 lbs.  This was effected both by
gradual increase in the power and size of the engines used and
by great improvement in their detailed design (by increasing
compression ratio and saving weight whenever possible); with the
result that the motive power of single-seater aeroplanes rose
from 80 and 100 horse-power in 1914 to an average of 200 to 300
horse-power, while the actual weight of the engine fell from 3
1/2-4 lbs. per horse-power to an average of 2 1/2 lbs. per
horse-power.  This meant that while a pre-war engine of 100
horse-power would weigh some 400 lbs., the 1918 engine developing
three times the power would have less than double the weight. 
The result of this improvement was that a scout aeroplane at the
time of the Armistice would have 1 horse-power for every 8 lbs.
of weight lifted, compared with the 20 or 25 lbs. of its 1914
predecessors.  This produced a considerable increase in the rate
of climb, a good postwar machine being able to reach 10,000 feet
in about 5 minutes and 20,000 feet in under half an hour.  The
loading per square foot was also considerably increased; this
being rendered possible both by improvement in the design of wing
sections and by more scientific construction giving increased
strength.  It will be remembered that in the machine of the very
early period each square foot of surface had only to lift a
weight of some 1 1/2 to 2 lbs., which by 1914 had been increased
to about 4 lbs.  By 1918 aeroplanes habitually had a loading of 8
lbs. or more per square foot of area; which resulted in great
increase in speed.  Although a speed of 126 miles per hour had
been attained by a specially designed racing machine over a short
distance in 1914, the average at that period little exceeded, if
at all, 100 miles per hour; whereas in 1918 speeds of 130 miles
per hour had become a commonplace, and shortly afterwards a speed
of over 166 miles an hour was achieved.

In another direction, also, that of size, great developments
were made.  Before the War a few machines fitted with more than
one engine had been built (the first being a triple
Gnome-engined biplane built by Messrs Short Bros. at Eastchurch
in 1913), but none of large size had been successfully produced,
the total weight probably in no case exceeding about 2 tons.  In
1916, however, the twin engine Handley-Page biplane was
produced, to be followed by others both in this country and
abroad, which represented a very great increase in size and,
consequently, load-carrying capacity.  By the end of the War
period several types were in existence weighing a total of 10
tons when fully loaded, of which some 4 tons or more represented
'useful load' available for crew, fuel, and bombs or passengers. 
This was attained through very careful attention to detailed
design, which showed that the material could be employed more
efficiently as size increased, and was also due to the fact that
a large machine was not liable to be put through the same
evolutions as a small machine, and therefore could safely be
built with a lower factor of safety.  Owing to the fact that a
wing section which is adopted for carrying heavy loads usually
has also a somewhat low lift to drag ratio, and is not therefore
productive of high speed, these machines are not as fast as
light scouts; but, nevertheless, they proved themselves capable
of achieving speeds of 100 miles an hour or more in some cases;
which was faster than the average small machine of 1914.

In one respect the development during the War may perhaps have
proved to be somewhat disappointing, as it might have been
expected that great improvements would be effected in metal
construction, leading almost to the abolition of wooden
structures.  Although, however, a good deal of experimental work
was done which resulted in overcoming at any rate the worst of
the difficulties, metal-built machines were little used (except
to a certain extent in Germany) chiefly on account of the need
for rapid production and the danger of delay resulting from
switching over from known and tried methods to experimental
types of construction.  The Germans constructed some large
machines, such as the giant Siemens-Schukhert machine, entirely
of metal except for the wing covering, while the Fokker and
Junker firms about the time of the Armistice in 1918 both
produced monoplanes with very deep all-metal wings (including
the covering) which were entirely unstayed externally, depending
for their strength on internal bracing.  In Great Britain cable
bracing gave place to a great extent to 'stream-line wires,'
which are steel rods rolled to a more or less oval section,
while tie-rods were also extensively used for the internal
bracing of the wings.  Great developments in the economical use
of material were also made in the direction of using built-up
main spars for the wings and interplane struts; spars composed
of a series of layers (or 'laminations') of different pieces of
wood also being used.

Apart from the metallic construction of aeroplanes an enormous
amount of work was done in the testing of different steels and
light alloys for use in engines, and by the end of the War
period a number of aircraft engines were in use of which the
pistons and other parts were of such alloys; the chief
difficulty having been not so much in the design as in the
successful heat-treatment and casting of the metal.

An important development in connection with the inspection and
testing of aircraft parts, particularly in the case of metal,
was the experimental application of X-ray photography, which
showed up latent defects, both in the material and in
manufacture, which would otherwise have passed unnoticed.  This
method was also used to test the penetration of glue into the
wood on each side of joints, so giving a measure of the
strength;  and for the effect of 'doping' the wings, dope being a
film (of cellulose acetate dissolved in acetone with other
chemicals) applied to the covering of wings and bodies to render
the linen taut and weatherproof, besides giving it a smooth
surface for the lessening of 'skin friction' when passing rapidly
through the air.

An important result of this experimental work was that it in
many cases enabled designers to produce aeroplane parts from
less costly material than had previously been considered
necessary, without impairing the strength.  It may be mentioned
that it was found undesirable to use welded joints on aircraft
in any part where the material is subjectto a tensile or bending
load, owing to the danger resulting from bad workmanship causing
the material to become brittle--an effect which cannot be
discovered except by cutting through the weld, which, of course,
involves a test to destruction.  Written, as it has been, in
August, 1920, it is impossible in this chapter to give any
conception of how the developments of War will be applied to
commercial aeroplanes, as few truly commercial machines have yet
been designed, and even those still show distinct traces of the
survival of war mentality.  When, however, the inevitable
recasting of ideas arrives, it will become evident, whatever the
apparent modification in the relative importance of different
aspects of design, that enormous advances were made under the
impetus of War which have left an indelible mark on progress.

We have, during the seventeen years since aeroplanes first took
the air, seen them grow from tentative experimental structures
of unknown and unknowable performance to highly scientific
products, of which not only the performances (in speed,
load-carrying capacity, and climb) are known, but of which the
precise strength and degree of stability can be forecast with
some accuracy on the drawing board.  For the rest, with the
future lies--apart from some revolutionary change in fundamental
design--the steady development of a now well-tried and well-found
engineering structure.



PART III

AEROSTATICS

I. BEGINNINGS

Francesco Lana, with his 'aerial ship,' stands as one of the
first great exponents of aerostatics; up to the time of the
Montgolfier and Charles balloon experiments, aerostatic and
aerodynamic research are so inextricably intermingled that it
has been thought well to treat of them as one, and thus the work
of Lana, Veranzio and his parachute, Guzman's frauds, and the
like, have already been sketched.  In connection with Guzman,
Hildebrandt states in his Airships Past and Present, a fairly
exhaustive treatise on the subject up to 1906, the year of its
publication, that there were two inventors--or
charlatans--Lorenzo de Guzman and a monk Bartolemeo Laurenzo,
the former of whom constructed an unsuccessful airship out of a
wooden basket covered with paper, while the latter made certain
experiments with a machine of which no description remains.  A
third de Guzman, some twenty-five years later, announced that he
had constructed a flying machine, with which he proposed to fly
from a tower to prove his success to the public.  The lack of
record of any fatal accident overtaking him about that time
seems to show that the experiment was not carried out.

Galien, a French monk, published a book L'art de naviguer dans
l'air in 1757, in which it was conjectured that the air at high
levels was lighter than that immediately over the surface of
the earth.  Galien proposed to bring down the upper layers of
air and with them fill a vessel, which by Archimidean principle
would rise through the heavier atmosphere.  If one went high
enough, said Galien, the air would be two thousand times as
light as water, and it would be possible to construct an
airship, with this light air as lifting factor, which should be
as large as the town of Avignon, and carry four million
passengers with their baggage.  How this high air was to be
obtained is matter for conjecture--Galien seems to have thought
in a vicious circle, in which the vessel that must rise to
obtain the light air must first be filled with it in order to
rise.

Cavendish's discovery of hydrogen in 1776 set men thinking, and
soon a certain Doctor Black was suggesting that vessels might be
filled with hydrogen, in order that they might rise in the air. 
Black, however, did not get beyond suggestion; it was Leo
Cavallo who first made experiments with hydrogen, beginning with
filling soap bubbles, and passing on to bladders and special
paper bags.  In these latter the gas escaped, and Cavallo was
about to try goldbeaters' skin at the time that the Montgolfiers
came into the field with their hot air balloon.

Joseph and Stephen Montgolfier, sons of a wealthy French paper
manufacturer, carried out many experiments in physics, and
Joseph interested himself in the study of aeronautics some time
before the first balloon was constructed by the brothers--he is
said to have made a parachute descent from the roof of his house
as early as 1771, but of this there is no proof.  Galien's idea,
together with study of the movement of clouds, gave Joseph some
hope of achieving aerostation through Galien's schemes, and the
first experiments were made by passing steam into a receiver,
which, of course, tended to rise--but the rapid condensation of
the steam prevented the receiver from more than threatening
ascent.  The experiments were continued with smoke, which
produced only a slightly better effect, and, moreover, the paper
bag into which the smoke was induced permitted of escape through
its pores; finding this method a failure the brothers desisted
until Priestley's work became known to them, and they conceived
the use of hydrogen as a lifting factor.  Trying this with paper
bags, they found that the hydrogen escaped through the pores of
the paper.

Their first balloon, made of paper, reverted to the hot-air
principle; they lighted a fire of wool and wet straw under the
balloon--and as a matter of course the balloon took fire after
very little experiment; thereupon they constructed a second,
having a capacity of 700 cubic feet, and this rose to a height
of over 1,000 feet.  Such a success gave them confidence, and
they gave their first public exhibition on June 5th, 1783, with
a balloon constructed of paper and of a circumference of 112
feet.  A fire was lighted under this balloon, which, after
rising to a height of 1,000 feet, descended through the cooling
of the air inside a matter of ten minutes.  At this the Academie
des Sciences invited the brothers to conduct experiments in
Paris.

The Montgolfiers were undoubtedly first to send up balloons, but
other experimenters were not far behind them, and before they
could get to Paris in response to their invitation, Charles, a
prominent physicist of those days, had constructed a balloon of
silk, which he proofed against escape of gas with rubber--the
Roberts had just succeeded in dissolving this substance to
permit of making a suitable coating for the silk.  With a
quarter of a ton of sulphuric acid, and half a ton of iron
filings and turnings, sufficient hydrogen was generated in four
days to fill Charles's balloon, which went up on August 28th,
1783.  Although the day was wet, Paris turned out to the number
of over 300,000 in the Champs de Mars, and cannon were fired to
announce the ascent of the balloon.  This, rising very rapidly,
disappeared amid the rain clouds, but, probably bursting through
no outlet being provided to compensate for the escape of gas,
fell soon in the neighbourhood of Paris.  Here peasants,
ascribing evil supernatural influence to the fall of such a
thing from nowhere, went at it with the implements of their
craft--forks, hoes, and the like--and maltreated it severely,
finally attaching it to a horse's tail and dragging it about
until it was mere rag and scrap.

Meanwhile, Joseph Montgolfier, having come to Paris, set about
the construction of a balloon out of linen; this was in three
diverse sections, the top being a cone 30 feet in depth, the
middle a cylinder 42 feet in diameter by 26 feet in depth, and
the bottom another cone 20 feet in depth from junction with the
cylindrical portion to its point.  The balloon was both lined
and covered with paper, decorated in blue and gold.  Before ever
an ascent could be attempted this ambitious balloon was caught
in a heavy rainstorm which reduced its paper covering to pulp
and tore the linen at its seams, so that a supervening strong
wind tore the whole thing to shreds.

Montgolfier's next balloon was spherical, having a capacity of
52,000 cubic feet.  It was made from waterproofed linen, and on
September 19th, 1783, it made an ascent for the palace courtyard
at Versailles, taking up as passengers a cock, a sheep, and a
duck.  A rent at the top of the balloon caused it to descend
within eight minutes, and the duck and sheep were found none the
worse for being the first living things to leave the earth in a
balloon, but the cock, evidently suffering, was thought to have
been affected by the rarefaction of the atmosphere at the
tremendous height reached--for at that time the general opinion
was that the atmosphere did not extend more than four or five
miles above the earth's surface.  It transpired later that the
sheep had trampled on the cock, causing more solid injury than
any that might be inflicted by rarefied air in an eight-minute
ascent and descent of a balloon.

For achieving this flight Joseph Montgolfier received from the
King of France a pension of  of L40, while Stephen was given
the order of St Michael, and a patent of nobility was granted to
their father.  They were made members of the Legion d'Honneur,
and a scientific deputation, of which Faujas de Saint-Fond, who
had raised the funds with which Charles's hydrogen balloon was
constructed, presented to Stephen Montgolfier a gold medal
struck in honour of his aerial conquest.  Since Joseph appears
to have had quite as much share in the success as Stephen, the
presentation of the medal to one brother only was in
questionable taste, unless it was intended to balance Joseph's
pension.

Once aerostation had been proved possible, many people began the
construction of small balloons--the wholehole thing was regarded
as a matter of spectacles and a form of amusement by the great
majority.  A certain Baron de Beaumanoir made the first balloon
of goldbeaters' skin, this being eighteen inches in diameter, and
using hydrogen as a lifting factor.  Few people saw any
possibilities in aerostation, in spite of the adventures of the
duck and sheep and cock; voyages to the moon were talked and
written, and there was more of levity than seriousness over
ballooning as a rule.  The classic retort of Benjamin Franklin
stands as an exception to the general rule:  asked what was the
use of ballooning--'What's the use of a baby?' he countered, and
the spirit of that reply brought both the dirigible and the
aeroplane to being, later.

The next noteworthy balloon was one by Stephen Montgolfier,
designed to take up passengers, and therefore of rather large
dimensions, as these things went then.  The capacity was 100,000
cubic feet, the depth being 85 feet, and the exterior was very
gaily decorated.  A short, cylindrical opening was made at the
lower extremity, and under this a fire-pan was suspended, above
the passenger car of the balloon.  On October 15th, 1783,
Pilatre de Rozier made the first balloon ascent--but the balloon
was held captive, and only allowed to rise to a height of 80
feet.  But, a little later in 1783, Rozier secured the honour
of making the first ascent in a free balloon, taking up with him
the Marquis d'Arlandes.  It had been originally intended that
two criminals, condemned to death, should risk their lives in
the perilous venture, with the prospect of a free pardon if they
made a safe descent, but d'Arlandes got the royal consent to
accompany Rozier, and the criminals lost their chance.  Rozier
and d'Arlandes made a voyage lasting for twenty-five minutes,
and, on landing, the balloon collapsed with such rapidity as
almost to suffocate Rozier, who, however, was dragged out to
safety by d'Arlandes.  This first aerostatic journey took place
on November 21st, 1783.

Some seven months later, on June 4th, 1784, a Madame Thible
ascended in a free balloon, reaching a height of 9,000 feet, and
making a journey which lasted for forty-five minutes--the great
King Gustavus of Sweden witnessed this ascent.  France grew used
to balloon ascents in the course of a few months, in spite of
the brewing of such a storm as might have been calculated to
wipe out all but purely political interests.  Meanwhile,
interest in the new discovery spread across the Channel, and on
September 15th, 1784, one Vincent Lunardi made the first balloon
voyage in England, starting from the Artillery Ground at
Chelsea, with a cat and dog as passengers, and landing in a
field in the parish of Standon, near Ware.  There is a rather
rare book which gives a very detailed account of this first
ascent in England, one copy of which is in the library of the
Royal Aeronautical Society; the venturesome Lunardi won a
greater measure of fame through his exploit than did Cody for
his infinitely more courageous and--from a scientific point of
view--valuable first aeroplane ascent in this country.

The Montgolfier type of balloon, depending on hot air for its
lifting power, was soon realised as having dangerous
limitations.  There was always a possibility of the balloon
catching fire while it was being filled, and on landing there
was further danger from the hot pan which kept up the supply of
hot air on the voyage --the collapsing balloon fell on the pan,
inevitably.  The scientist Saussure, observing the filling of
the balloons very carefully, ascertained that it was rarefaction
of the air which was responsible for the lifting power, and not
the heat in itself, and, owing to the rarefaction of the air at
normal temperature at great heights above the earth, the limit
of ascent for a balloon of the Montgolfier type was estimated by
him at under 9,000 feet.  Moreover, since the amount of fuel
that could be carried for maintaining the heat of the balloon
after inflation was subject to definite limits, prescribed by
the carrying capacity of the balloon, the duration of the
journey was necessarily limited just as strictly.

These considerations tended to turn the minds of those
interested in aerostation to consideration of the hydrogen
balloon evolved by Professor Charles.  Certain improvements had
been made by Charles since his first construction; he employed
rubber-coated silk in the construction of a balloon of 30 feet
diameter, and provided a net for distributing the pressure
uniformly over the surface of the envelope; this net covered the
top half of the balloon, and from its lower edge dependent ropes
hung to join on a wooden ring, from which the car of the balloon
was suspended--apart from the extension of the net so as to
cover in the whole of the envelope, the spherical balloon of
to-day is virtually identical with that of Charles in its method
of construction.  He introduced the valve at the top of the
balloon, by which escape of gas could be controlled, operating
his valve by means of ropes which depended to the car of the
balloon, and he also inserted a tube, of about 7 inches
diameter, at the bottom of the balloon, not only for purposes of
inflation, but also to provide a means of escape for gas in case
of expansion due to atmospheric conditions.

Sulphuric acid and iron filings were used by Charles for filling
his balloon, which required three days and three nights for the
generation of its 14,000 cubic feet of hydrogen gas.  The
inflation was completed on December 1st, 1783, and the fittings
carried included a barometer and a grapnel form of anchor.  In
addition to this, Charles provided the first 'ballon sonde' in
the form of a small pilot balloon which he handed to Montgolfier
to launch before his own ascent, in order to determine the
direction and velocity of the wind.  It was a graceful compliment
to his rival, and indicated that, although they were both working
to the one end, their rivalry was not a matter of bitterness.

Ascending on December 1st, 1783, Charles took with him one of
the brothers Robert, and with him made the record journey up to
that date, covering a period of three and three-quarter hours,
in which time they journeyed some forty miles.  Robert then
landed, and Charles ascended again alone, reaching such a height
as to feel the effects of the rarefaction of the air, this very
largely due to the rapidity of his ascent.  Opening the valve at
the top of the balloon, he descended thirty-five minutes after
leaving Robert behind, and came to earth a few miles from the
point of the first descent.  His discomfort over the rapid
ascent was mainly due to the fact that, when Robert landed, he
forgot to compensate for the reduction of weight by taking in
further ballast, but the ascent proved the value of the tube at
the bottom of the balloon envelope, for the gas escaped very
rapidly in that second ascent, and, but for the tube, the
balloon must inevitably have burst in the air, with fatal
results for Charles.

As in the case of aeroplane flight, as soon as the balloon was
proved practicable the flight across the English Channel was
talked of, and Rozier, who had the honour of the first flight,
announced his intention of being first to cross.  But Blanchard,
who had an idea for a 'flying car,' anticipated him, and made a
start from Dover on January 7th, 1785, taking with him an
American doctor named Jeffries.  Blanchard fitted out his craft
for the journey very thoroughly, taking provisions, oars, and
even wings, for propulsion in case of need.  He took so much, in
fact, that as soon as the balloon lifted clear of the ground the
whole of the ballast had to be jettisoned, lest the balloon
should drop into the sea.  Half-way across the Channel the
sinking of the balloon warned Blanchard that he had to part with
more than ballast to accomplish the journey, and all the
equipment went, together with certain books and papers that were
on board the car.  The balloon looked perilously like
collapsing, and both Blanchard and Jeffries began to undress in
order further to lighten their craft--Jeffries even proposed a
heroic dive to save the situation, but suddenly the balloon rose
sufficiently to clear the French coast, and the two voyagers
landed at a point near Calais in the Forest of Gaines, where a
marble column was subsequently erected to commemorate the great
feat.

Rozier, although not first across, determined to be second, and
for that purpose he constructed a balloon which was to owe its
buoyancy to a combination of the hydrogen and hot air
principles.  There was a spherical hydrogen balloon above, and
beneath it a cylindrical container which could be filled with
hot air, thus compensating for the leakage of gas from the
hydrogen portion of the balloon--regulating the heat of his
fire, he thought, would give him perfect control in the matter of
ascending and descending.

On July 6th, 1785, a favourable breeze gave Rozier his
opportunity of starting from the French coast, and with a
passenger aboard he cast off in his balloon, which he had named
the 'Aero-Montgolfiere.'  There was a rapid rise at first, and
then for a time the balloon remained stationary over the land,
after which a cloud suddenly appeared round the balloon,
denoting that an explosion had taken place.  Both Rozier and his
companion were killed in the fall, so that he, first to leave
the earth by balloon, was also first victim to the art of
aerostation.

There followed, naturally, a lull in the enthusiasm with which
ballooning had been taken up, so far as France was concerned. 
In Italy, however, Count Zambeccari took up hot-air ballooning,
using a spirit lamp to give him buoyancy, and on the first
occasion when the balloon car was set on fire Zambeccari let
down his passenger by means of the anchor rope, and managed to
extinguish the fire while in the air.  This reduced the buoyancy
of the balloon to such an extent that it fell into the Adriatic
and was totally wrecked, Zambeccari being rescued by fishermen. 
He continued to experiment up to 1812, when he attempted to
ascend at Bologna; the spirit in his lamp was upset by the
collision of the car with a tree, and the car was again set on
fire.  Zambeccari jumped from the car when it was over fifty feet
above level ground, and was killed.  With him the Rozier type of
balloon, combining the hydrogen and hot air principles,
disappeared; the combination was obviously too dangerous to be
practical.

The brothers Robert were first to note how the heat of the sun
acted on the gases within a balloon envelope, and it has since
been ascertained that sun rays will heat the gas in a balloon to
as much as 80 degrees Fahrenheit greater temperature than the
surrounding atmosphere; hydrogen, being less affected by change
of temperature than coal gas, is the most suitable filling
element, and coal gas comes next as the medium of buoyancy.  This
for the free and non-navigable balloon, though for the airship,
carrying means of combustion, and in military work liable to
ignition by explosives, the gas helium seems likely to replace
hydrogen, being non-combustible.

In spite of the development of the dirigible airship, there
remains work for the free, spherical type of balloon in the
scientific field.  Blanchard's companion on the first Channel
crossing by balloon, Dr Jeffries, was the first balloonist to
ascend for purely scientific purposes; as early as 1784 he made
an ascent to a height of 9,000 feet, and observed a fall in
temperature of from degrees--at the level of London, where he
began his ascent--to 29 degrees at the maximum height reached. 
He took up an electrometer, a hydrometer, a compass, a
thermometer, and a Toricelli barometer, together with bottles of
water, in order to collect samples of the air at different
heights.  In 1785 he made a second ascent, when trigonometrical
observations of the height of the balloon were made from the
French coast, giving an altitude of 4,800 feet.

The matter was taken up on its scientific side very early in
America, experiments in Philadelphia being almost simultaneous
with those of the Montgolfiers in France.  The flight of Rozier
and d'Arlandes inspired two members of the Philadelphia
Philosophical Academy to construct a balloon or series of
balloons of their own design; they made a machine which consisted
of no less than 47 small hydrogen balloons attached to a wicker
car, and made certain preliminary trials, using animals as
passengers.  This was followed by a captive ascent with a man as
passenger, and eventually by the first free ascent in America,
which was undertaken by one James Wilcox, a carpenter, on
December 28th, 1783.  Wilcox, fearful of falling into a river,
attempted to regulate his landing by cutting slits in some of the
supporting balloons, which was the method adopted for regulating
ascent or descent in this machine.  He first cut three, and then,
finding that the effect produced was not sufficient, cut three
more, and then another five--eleven out of the forty-seven.  The
result was so swift a descent that he dislocated his wrist on
landing.

            A NOTE ON BALLONETS OR AIR BAGS.

Meusnier, toward the end of the eighteenth century, was first to
conceive the idea of compensating for the loss of gas due to
expansion by fitting to the interior of a free balloon a
ballonet, or air bag, which could be pumped full of air so as to
retain the shape and rigidity of the envelope.

The ballonet became particularly valuable as soon as airship
construction became general, and it was in the course of advance
in Astra Torres design that the project was introduced of using
the ballonets in order to give inclination from the horizontal. 
In the earlier Astra Torres, trimming was accomplished by moving
the car fore and aft--this in itself was an advance on the
separate 'sliding weigh' principle--and this was the method
followed in the Astra Torres bought by the British Government
from France in 1912 for training airship pilots.  Subsequently,
the two ballonets fitted inside the envelope were made to serve
for trimming by the extent of their inflation, and this method of
securing inclination proved the best until exterior rudders, and
greater engine power, supplanted it, as in the Zeppelin and, in
fact, all rigid types.

In the kite balloon, the ballonet serves the purpose of a
rudder, filling itself through the opening being kept pointed
toward the wind--there is an ingenious type of air scoop with
non-return valve which assures perfect inflation.  In the S.S.
type of airship, two ballonets are provided, the supply of air
being taken from the propeller draught by a slanting aluminium
tube to the underside of the envelope, where it meets a
longitudinal fabric hose which connects the two ballonet air
inlets.  In this hose the non-return air valves, known as
'crab-pots,' are fitted, on either side of the junction with the
air-scoop.  Two automatic air valves, one for each ballonet, are
fitted in the underside of the envelope, and, as the air
pressure tends to open these instead of keeping them shut, the
spring of the valve is set inside the envelope.  Each spring is
set to open at a pressure of 25 to 28 mm.



II. THE FIRST DIRIGIBLES

Having got off the earth, the very early balloonists set about
the task of finding a means of navigating the air but, lacking
steam or other accessory power to human muscle, they failed to
solve the problem.  Joseph Montgolfier speedily exploded the
idea of propelling a balloon either by means of oars or sails,
pointing out that even in a dead calm a speed of five miles an
hour would be the limit achieved.  Still, sailing balloons were
constructed, even up to the time of Andree, the explorer, who
proposed to retard the speed of the balloon by ropes dragging on
the ground, and then to spread a sail which should catch the
wind and permit of deviation of the course.  It has been proved
that slight divergences from the course of the wind can be
obtained by this means, but no real navigation of the air could
be thus accomplished.

Professor Wellner, of Brunn, brought up the idea of a sailing
balloon in more practical fashion in 1883.  He observed that
surfaces inclined to the horizontal have a slight lateral motion
in rising and falling, and deduced that by alternate lowering
and raising of such surfaces he would be able to navigate the
air, regulating ascent and descent by increasing or decreasing
the temperature of his buoyant medium in the balloon.  He
calculated that a balloon, 50 feet in diameter and 150 feet in
length, with a vertical surface in front and a horizontal
surface behind, might be navigated at a speed of ten miles per
hour, and in actual tests at Brunn he proved that a single rise
and fall moved the balloon three miles against the wind.  His
ideas were further developed by Lebaudy in the construction of
the early French dirigibles.

According to Hildebrandt,[*] the first sailing balloon was built
in 1784 by Guyot, who made his balloon egg-shaped, with the
smaller end at the back and the longer axis horizontal; oars
were intended to propel the craft, and naturally it was a
failure.  Carra proposed the use of paddle wheels, a step in the
right direction, by mounting them on the sides of the car, but
the improvement was only slight.  Guyton de Morveau, entrusted
by the Academy of Dijon with the building of a sailing balloon,
first used a vertical rudder at the rear end of his
construction--it survives in the modern dirigible.  His
construction included sails and oars, but, lacking steam or
other than human propulsive power, the airship was a failure
equally with Guyot's.

[*] Airships Past and Present.

Two priests, Miollan and Janinet, proposed to drive balloons
through the air by the forcible expulsion of the hot air in the
envelope from the rear of the balloon.  An opening was made
about half-way up the envelope, through which the hot air was to
escape, buoyancy being maintained by a pan of combustibles in
the car.  Unfortunately, this development of the Montgolfier type
never got a trial, for those who were to be spectators of the
first flight grew exasperated at successive delays, and in the
end, thinking that the balloon would never rise, they destroyed
it.

Meusnier, a French general, first conceived the idea of
compensating for loss of gas by carrying an air bag inside the
balloon, in order to maintain the full expansion of the
envelope.  The brothers Robert constructed the first balloon in
which this was tried and placed the air bag near the neck of the
balloon which was intended to be driven by oars, and steered by
a rudder.  A violent swirl of wind which was encountered on the
first ascent tore away the oars and rudder and broke the ropes
which held the air bag in position; the bag fell into the
opening of the neck and stopped it up, preventing the escape of
gas under expansion.  The Duc de Chartres, who was aboard,
realised the extreme danger of the envelope bursting as the
balloon ascended, and at 16,000 feet he thrust a staff through
the envelope--another account says that he slit it with his
sword--and thus prevented disaster.  The descent after this rip
in the fabric was swift, but the passengers got off without
injury in the landing.

Meusnier, experimenting in various ways, experimented with
regard to the resistance offered by various shapes to the air,
and found that an elliptical shape was best; he proposed to make
the car boat--shaped, in order further to decrease the
resistance, and he advocated an entirely rigid connection
between the car and the body of the balloon, as indispensable to
a dirigible.[*]  He suggested using three propellers, which were
to be driven by hand by means of pulleys, and calculated that a
crew of eighty would be required to furnish sufficient motive
power.  Horizontal fins were to be used to assure stability, and
Meusnier thoroughly investigated the pressures exerted by gases,
in order to ascertain the stresses to which the envelope would be
subjected.  More important still, he went into detail with
regard to the use of air bags, in order to retain the shape of
the balloon under varying pressures of gas due to expansion and
consequent losses; he proposed two separate envelopes, the inner
one containing gas, and the space between it and the outer one
being filled with air.  Further, by compressing the air inside
the air bag, the rate of ascent or descent could be regulated. 
Lebaudy, acting on this principle, found it possible to pump air
at the rate of 35 cubic feet per second, thus making good loss
of ballast which had to be thrown overboard.

[*] Hildebrandt.

Meusnier's balloon, of course, was never constructed, but his
ideas have been of value to aerostation up to the present time. 
His career ended in the revolutionary army in 1793, when he was
killed in the fighting before Mayence, and the King of Prussia
ordered all firing to cease until Meusnier had been buried.  No
other genius came forward to carry on his work, and it was
realised that human muscle could not drive a balloon with
certainty through the air; experiment in this direction was
abandoned for nearly sixty years, until in 1852 Giffard
brought the first practicable power-driven dirigible to being.

Giffard, inventor of the steam injector, had already made
balloon ascents when he turned to aeronautical propulsion, and
constructed a steam engine of 5 horsepower with a weight of only
100 lbs.--a great achievement for his day.  Having got his
engine, he set about making the balloon which it was to drive;
this he built with the aid of two other enthusiasts, diverging
from Meusnier's ideas by making the ends pointed, and keeping the
body narrowed from Meusnier's ellipse to a shape more resembling
a rather fat cigar.  The length was 144 feet, and the greatest
diameter only 40 feet, while the capacity was 88,000 cubic feet. 
A net which covered the envelope of the balloon supported a
spar, 66 feet in length, at the end of which a triangular sail
was placed vertically to act as rudder.  The car, slung 20 feet
below the spar, carried the engine and propeller.  Engine and
boiler together weighed 350 lbs., and drove the 11 foot
propeller at 110 revolutions per minute.

As precaution against explosion, Giffard arranged wire gauze in
front of the stoke-hole of his boiler, and provided an exhaust
pipe which discharged the waste gases from the engine in a
downward direction.  With this first dirigible he attained to a
speed of between 6 and 8 feet per second, thus proving that the
propulsion of a balloon was a possibility, now that steam had
come to supplement human effort.

Three years later he built a second dirigible, reducing the
diameter and increasing the length of the gas envelope, with a
view to reducing air resistance.  The length of this was 230
feet, the diameter only 33 feet, and the capacity was 113,000
cubic feet, while the upper part of the envelope, to which the
covering net was attached, was specially covered to ensure a
stiffening effect.  The car of this dirigible was dropped rather
lower than that of the first machine, in order to provide more
thoroughly against the danger of explosions.  Giffard, with a
companion named Yon as passenger, took a trial trip on this
vessel, and made a journey against the wind, though slowly.  In
commencing to descend, the nose of the envelope tilted upwards,
and the weight of the car and its contents caused the net to
slip, so that just before the dirigible reached the ground, the
envelope burst.  Both Giffard and his companion escaped with very
slight injuries.

Plans were immediately made for the construction of a third
dirigible, which was to be 1,970 feet in length, 98 feet in
extreme diameter, and to have a capacity of 7,800,000 cubic feet
of gas.  The engine of this giant was to have weighed 30 tons,
and with it Giffard expected to attain a speed of 40 miles per
hour.  Cost prevented the scheme being carried out, and Giffard
went on designing small steam engines until his invention of the
steam injector gave him the funds to turn to dirigibles again. 
He built a captive balloon for the great exhibition in London in
1868, at a cost of nearly L30,000, and designed a dirigible
balloon which was to have held a million and three quarters
cubic feet of gas, carry two boilers, and cost about L40,000. 
The plans were thoroughly worked out, down to the last detail,
but the dirigible was never constructed.  Giffard went blind, and
died in 1882--he stands as the great pioneer of dirigible
construction, more on the strength of the two vessels which he
actually built than on that of the ambitious later conceptions
of his brain.

In 1872 Dupuy de Lome, commissioned by the French government,
built a dirigible which he proposed to drive by man-power--it
was anticipated that the vessel would be of use in the siege of
Paris, but it was not actually tested till after the conclusion
of the war.  The length of this vessel was 118 feet, its
greatest diameter 49 feet, the ends being pointed, and the
motive power was by a propeller which was revolved by the
efforts of eight men.  The vessel attained to about the same
speed as Giffard's steam-driven airship; it was capable of
carrying fourteen men, who, apart from these engaged in driving
the propeller, had to manipulate the pumps which controlled the
air bags inside the gas envelope.

In the same year Paul Haenlein, working in Vienna, produced an
airship which was a direct forerunner of the Lebaudy type, 164
feet in length, 30 feet greatest diameter, and with a cubic
capacity of 85,000 feet.  Semi-rigidity was attained by placing
the car as close to the envelope as possible, suspending it by
crossed ropes, and the motive power was a gas engine of the
Lenoir type, having four horizontal cylinders, and giving about
5 horse-power with a consumption of about 250 cubic feet of gas
per hour.  This gas was sucked from the envelope of the balloon,
which was kept fully inflated by pumping in compensating air to
the air bags inside the main envelope.  A propeller, 15 feet in
diameter, was driven by the Lenoir engine at 40 revolutions per
minute.  This was the first instance of the use of an internal
combustion engine in connection with aeronautical experiments.

The envelope of this dirigible was rendered airtight by means of
internal rubber coating, with a thinner film on the outside. 
Coal gas, used for inflation, formed a suitable fuel for the
engine, but limited the height to which the dirigible could
ascend.  Such trials as were made were carried out with the
dirigible held captive, and a speed of I 5 feet per second was
attained.  Full experiment was prevented through funds running
low, but Haenlein's work constituted a distinct advance on all
that had been done previously.

Two brothers, Albert and Gaston Tissandier, were next to enter
the field of dirigible construction; they had experimented with
balloons during the Franc-Prussian War, and had attempted to get
into Paris by balloon during the siege, but it was not until
1882 that they produced their dirigible.

This was 92 feet in length and 32 feet in greatest diameter,
with a cubic capacity of 37,500 feet, and the fabric used was
varnished cambric.  The car was made of bamboo rods, and in
addition to its crew of three, it carried a Siemens dynamo, with
24 bichromate cells, each of which weighed 17 lbs.  The motor
gave out 1 1/2 horse-power, which was sufficient to drive the
vessel at a speed of up to 10 feet per second.  This was not so
good as Haenlein's previous attempt and, after L2,000 had been
spent, the Tissandier abandoned their experiments, since a 5-mile
breeze was sufficient to nullify the power of the motor.

Renard, a French officer who had studied the problem of
dirigible construction since 1878, associated himself first with
a brother officer named La Haye, and subsequently with another
officer, Krebs, in the construction of the second dirigible to
be electrically-propelled.  La Haye first approached Colonel
Laussedat, in charge of the Engineers of the French Army, with a
view to obtaining funds, but was refused, in consequence of the
practical failure of all experiments since 1870.  Renard, with
whom Krebs had now associated himself, thereupon went to
Gambetta, and succeeded in getting a promise of a grant of
L8,000 for the work; with this promise Renard and Krebs set to
work.

They built their airship in torpedo shape, 165 feet in length,
and of just over 27 feet greatest diameter--the greatest diameter
was at the front, and the cubic capacity was 66,000 feet.  The
car itself was 108 feet in length, and 4 1/2 feet broad, covered
with silk over the bamboo framework.  The 23 foot diameter
propeller was of wood, and was driven by an electric motor
connected to an accumulator, and yielding 8.5 horsepower.  The
sweep of the propeller, which might have brought it in contact
with the ground in landing, was counteracted by rendering it
possible to raise the axis on which the blades were mounted, and
a guide rope was used to obviate damage altogether, in case of
rapid descent.  There was also a 'sliding weight' which was
movable to any required position to shift the centre of gravity
as desired.  Altogether, with passengers and ballast aboard, the
craft weighed two tons.

In the afternoon of August 8th, 1884, Renard and Krebs ascended
in the dirigible--which they had named 'La France,' from the
military ballooning ground at Chalais-Meudon, making a circular
flight of about five miles, the latter part of which was in the
face of a slight wind.  They found that the vessel answered well
to her rudder, and the five-mile flight was made successfully in
a period of 23 minutes.  Subsequent experimental flights
determined that the air speed of the dirigible was no less than
14 1/2 miles per hour, by far the best that had so far been
accomplished in dirigible flight.  Seven flights in all were
made, and of these five were completely successful, the
dirigible returning to its starting point with no difficulty. On
the other two flights it had to be towed back.

Renard attempted to repeat his construction on a larger scale,
but funds would not permit, and the type was abandoned; the
motive power was not sufficient to permit of more than short
flights, and even to the present time electric motors, with
their necessary accumulators, are far too cumbrous to compete
with the self-contained internal combustion engine.  France had
to wait for the Lebaudy brothers, just as Germany had to wait
for Zeppelin and Parseval.

Two German experimenters, Baumgarten and Wolfert, fitted a
Daimler motor to a dirigible balloon which made its first ascent
at Leipzig in 1880.  This vessel had three cars, and placing a
passenger in one of the outer cars[*] distributed the load
unevenly, so that the whole vessel tilted over and crashed to
the earth, the occupants luckily escaping without injury.  After
Baumgarten's death, Wolfert determined to carry on with his
experiments, and, having achieved a certain measure of success,
he announced an ascent to take place on the Tempelhofer Field,
near Berlin, on June 12th, 1897.  The vessel, travelling with
the wind, reached a height of 600 feet, when the exhaust of the
motor communicated flame to the envelope of the balloon, and
Wolfert, together with a passenger he carried, was either killed
by the fall or burnt to death on the ground.  Giffard had taken
special precautions to avoid an accident of this nature, and
Wolfert, failing to observe equal care, paid the full penalty.

[*] Hildebrandt.

Platz, a German soldier, attempting an ascent on the Tempelhofer
Field in the Schwartz airship in 1897, merely proved the
dirigible a failure.  The vessel was of aluminium, 0.008  inch
in thickness, strengthened by an aluminium lattice work; the
motor was two-cylindered petrol-driven; at the first trial the
metal developed such leaks that the vessel came to the ground
within four miles of its starting point.  Platz, who was aboard 
alone as crew, succeeded in escaping by jumping clear before the
car touched earth, but the shock of alighting broke up the
balloon, and a following high wind completed the work of full
destruction.  A second account says that Platz, finding the
propellers insufficient to drive the vessel against the wind,
opened the valve and descended too rapidly.

The envelope of this dirigible was 156 feet in length, and the
method of filling was that of pushing in bags, fill them with
gas, and then pulling them to pieces and tearing them out of the
body of the balloon.  A second contemplated method of filling
was by placing a linen envelope inside the aluminium casing,
blowing it out with air, and then admitting the gas between the
linen and the aluminium outer casing.  This would compress the
air out of the linen envelope, which was to be withdrawn when
the aluminium casing had been completely filled with gas.

All this, however, assumes that the Schwartz type--the first
rigid dirigible, by the way--would prove successful.  As it
proved a failure on the first trial, the problem of filling it
did not arise again.

By this time Zeppelin, retired from the German army, had begun
to devote himself to the study of dirigible construction, and, a
year after Schwartz had made his experiment and had failed, he
got together sufficient funds for the formation of a
limitedliability company, and started on the construction of the
first of his series of airships.  The age of tentative
experiment was over, and, forerunner of the success of the
heavier-than-air type of flying machine, successful dirigible
flight was accomplished by Zeppelin in Germany, and by
Santos-Dumont in France.



III. SANTOS-DUMONT

A Brazilian by birth, Santos-Dumont began in Paris in the year
1898 to make history, which he subsequently wrote.  His book, My
Airships, is a record of his eight years of work on
lighter-than-air machines, a period in which he constructed no
less than fourteen dirigible balloons, beginning with a cubic
capacity of 6,350 feet, and an engine of 3 horse-power, and
rising to a cubic capacity of 71,000 feet on the tenth dirigible
he constructed, and an engine of 60 horse-power, which was
fitted to the seventh machine in order of construction, the one
which he built after winning the Deutsch Prize.

The student of dirigible construction is recommended to
Santos-Dumont's own book not only as a full record of his work,
but also as one of the best stories of aerial navigation that
has ever been written.  Throughout all his experiments, he
adhered to the non-rigid type; his first dirigible made its
first flight on September 18th, 1898, starting from the Jardin
d'Acclimatation to the west of Paris; he calculated that his 3
horse-power engine would yield sufficient power to enable him to
steer clear of the trees with which the starting-point was
surrounded, but, yielding to the advice of professional
aeronauts who were present, with regard to the placing of the
dirigible for his start, he tore the envelope against the trees. 
Two days later, having repaired the balloon, he made an ascent of
1,300 feet.  In descending, the hydrogen left in the balloon
contracted, and Santos-Dumont narrowly escaped a serious accident
in coming to the ground.

His second machine, built in the early spring of 1899, held over
7,000 cubic feet of gas and gave a further 44 lbs. of ascensional
force.  The balloon envelope was very long and very narrow; the
first attempt at flight was made in wind and rain, and the
weather caused sufficient contraction of the hydrogen for a wind
gust to double the machine up and toss it into the trees near its
starting-point. The inventor immediately set about the
construction of 'Santos-Dumont No. 3,' on which he made a number
of successful flights, beginning on November 13th, 1899.  On the
last of his flights, he lost the rudder of the machine and made a
fortunate landing at Ivry.  He did not repair the balloon,
considering it too clumsy in form and its motor too small. 
Consequently No. 4 was constructed, being finished on the 1st,
August, 1900.  It had a cubic capacity of 14,800 feet, a length
of 129 feet and greatest diameter of 16.7 feet, the power
plant being a 7 horse-power Buchet motor.  Santos-Dumont sat on
a bicycle saddle fixed to the long bar suspended under the
machine, which also supported motor propeller, ballast; and
fuel.  The experiment of placing the propeller at the stem
instead of at the stern was tried, and the motor gave it a speed
of 100 revolutions per minute.  Professor Langley witnessed the
trials of the machine, which proved before the members of the
International Congress of Aeronautics, on September 19th, that
it was capable of holding its own against a strong wind.

Finding that the cords with which his dirigible balloon cars were
suspended offered almost as much resistance to the air as did
the balloon itself, Santos-Dumont substituted piano wire and
found that the alteration constituted greater progress than many
a more showy device.  He altered the shape and size of his No. 4
to a certain extent and fitted a motor of 12 horse-power. 
Gravity was controlled by shifting weights worked by a cord;
rudder and propeller were both placed at the stern.  In
Santos-Dumont's book there is a certain amount of confusion
between the No. 4 and No. 5 airships, until he explains that
'No. 5' is the reconstructed 'No. 4.'  It was with No. 5 that
he won the Encouragement Prize presented by the Scientific
Commission of the Paris Aero Club.  This he devoted to the first
aeronaut who between May and October of 1900 should start from
St Cloud, round the Eiffel Tower, and return.  If not won in
that year, the prize was to remain open the following year from
May 1st to October 1st, and so on annually until won.  This was a
simplification of the conditions of the Deutsch Prize itself, the
winning of which involved a journey of 11 kilometres in 30
minutes.

The Santos-Dumont No. 5, which was in reality the modified No. 4
with new keel, motor, and propeller, did the course of the
Deutsch Prize, but with it Santos-Dumont made no attempt to win
the prize until July of 1901, when he completed the course in 40
minutes, but tore his balloon in landing.  On the 8th August,
with his balloon leaking, he made a second attempt, and narrowly
escaped disaster, the airship being entirely wrecked. Thereupon
he built No. 6 with a cubic capacity of 22,239 feet and a lifting
power of 1,518 lbs.

With this machine he won the Deutsch Prize on October 19th,
1901, starting with the disadvantage of a side wind of 20 feet
per second.  He reached the Eiffel Tower in 9 minutes and,
through miscalculating his turn, only just missed colliding
with it.  He got No. 6 under control again and succeeded in
getting back to his starting-point in 29 1/2 minutes, thus
winning the 125,000 francs which constituted the Deutsch Prize,
together with a similar sum granted to him by the Brazilian
Government for the exploit.  The greater part of this money was
given by Santos-Dumont to charities.

He went on building after this until he had made fourteen
non-rigid dirigibles; of these No. 12 was placed at the disposal
of the military authorities, while the rest, except for one that
was sold to an American and made only one trip, were matters of
experiment for their maker. His conclusions from his experiments
may be gathered from his own work:--

'On Friday, 31st July, 1903, Commandant Hirschauer and
Lieutenant-Colonel Bourdeaux spent the afternoon with me at my
airship station at Neuilly St James, where I had my three newest
airships--the racing 'No. 7,' the omnibus 'No. 10,' and the
runabout 'No. 9'--ready for their study.  Briefly, I may say
that the opinions expressed by the representatives of the
Minister of War were so unreservedly favourable that a practical
test of a novel character was decided to be made.  Should the
airship chosen pass successfully through it the result will be
conclusive of its military value.

'Now that these particular experiments are leaving my exclusively
private control I will say no more of them than what has been
already published in the French press.  The test will probably
consist of an attempt to enter one of the French frontier towns,
such as Belfort or Nancy, on the same day that the airship
leaves Paris.  It will not, of course, be necessary to make the
whole journey in the airship.  A military railway wagon may be
assigned to carry it, with its balloon uninflated, with tubes of
hydrogen to fill it, and with all the necessary machinery and
instruments arranged beside it.  At some station a short
distance from the town to be entered the wagon may be uncoupled
from the train, and a sufficient number of soldiers accompanying
the officers will unload the airship and its appliances,
transport the whole to the nearest open space, and at once begin
inflating the balloon.  Within two hours from quitting the train
the airship may be ready for its flight to the interior of the
technically-besieged town.

'Such may be the outline of the task--a task presented
imperiously to French balloonists by the events of 1870-1, and
which all the devotion and science of the Tissandier brothers
failed to accomplish.  To-day the problem may be set with better
hope of success.  All the essential difficulties may be revived
by the marking out of a hostile zone around the town that must
be entered; from beyond the outer edge of this zone, then, the
airship will rise and take its flight--across it.

'Will the airship be able to rise out of rifle range?  I have
always been the first to insist that the normal place of the
airship is in low altitudes, and I shall have written this book
to little purpose if I have not shown the reader the real
dangers attending any brusque vertical mounting to considerable
heights.  For this we have the terrible Severo accident before
our eyes.  In particular, I have expressed astonishment at
hearing of experimenters rising to these altitudes without
adequate purpose in their early stages of experience with
dirigible balloons.  All this is very different, however, from a
reasoned, cautious mounting, whose necessity has been foreseen
and prepared for.'

Probably owing to the fact that his engines were not of
sufficient power, Santos-Dumont cannot be said to have solved
the problem of the military airship, although the French
Government bought one of his vessels.  At the same time, he
accomplished much in furthering and inciting experiment with
dirigible airships, and he will always rank high among the
pioneers of aerostation.  His experiments might have gone
further had not the Wright brothers' success in America and
French interest in the problem of the heavier-than-air machine
turned him from the study of dirigibles to that of the
aeroplane, in which also he takes high rank among the pioneers,
leaving the construction of a successful military dirigible to
such men as the Lebaudy brothers, Major Parseval, and Zeppelin.



IV. THE MILITARY  DIRIGIBLE

Although French and German experiment in connection with the
production of an airship which should be suitable for military
purposes proceeded side by side, it is necessary to outline the
development in the two countries separately, owing to the
differing character of the work carried out.  So far as France
is concerned, experiment began with the Lebaudy brothers,
originally sugar refiners, who turned their energies to airship
construction in 1899.  Three years of work went to the production
of their first vessel, which was launched in 1902, having been
constructed by them together with a balloon manufacturer named
Surcouf and an engineer, Julliot.  The Lebaudy airships were
what is known as semi-rigids, having a spar which ran
practically the full length of the gas bag to which it was
attached in such a way as to distribute the load evenly.  The
car was suspended from the spar, at the rear end of which both
horizontal and vertical rudders were fixed, whilst stabilising
fins were provided at the stern of the gas envelope itself.  The
first of the Lebaudy vessels was named the 'Jaune'; its length
was 183 feet and its maximum diameter 30 feet, while the cubic
capacity was 80,000 feet.  The power unit was a 40 horse-power
Daimler motor, driving two propellers and giving a maximum speed
of 26 miles per hour.  This vessel made 29 trips, the last of
which took place in November, 1902, when the airship was wrecked
through collision with a tree.

The second airship of Lebaudy construction was 7 feet longer
than the first, and had a capacity of 94,000 cubic feet of gas
with a triple air bag of 17,500 cubic feet to compensate for
loss of gas; this latter was kept inflated by a rotary fan.  The
vessel was eventually taken over by the French Government and
may be counted the first dirigible airship considered fit on its
tests for military service.

Later vessels of the Lebaudy type were the 'Patrie' and
'Republique,' in which both size and method of construction
surpassed those of the two first attempts.  The 'Patrie' was
fitted with a 60 horse-power engine which gave a speed of 28
miles an hour, while the vessel had a radius of 280 miles,
carrying a crew of nine.  In the winter of 1907 the 'Patrie' was
anchored at Verdun, and encountered a gale which broke her hold
on her mooring-ropes.  She drifted derelict westward across
France, the Channel, and the British Isles, and was lost in the
Atlantic.

The 'Republique' had an 80 horse-power motor, which, however,
only gave her the same speed as the 'Patrie.'  She was launched
in July, 1908, and within three months came to an end which
constituted a tragedy for France.  A propeller burst while the
vessel was in the air, and one blade, flying toward the
envelope, tore in it a great gash; the airship crashed to earth,
and the two officers and two non-commissioned officers who were
in the car were instantaneously killed.

The Clement Bayard, and subsequently the Astra-Torres,
non-rigids, followed on the early Lebaudys and carried French
dirigible construction up to 1912.  The Clement Bayard was a
simple non-rigid having four lobes at the stern end to assist
stability.  These were found to retard the speed of the airship,
which in the second and more successful construction was driven
by a Clement Bayard motor of l00 horse-power at a speed of 30
miles an hour.  On August 23rd, 1909, while being tried for
acceptance by the military authorities, this vessel achieved a
record by flying at a height of 5,000 feet for two hours.  The
Astra-Torres non-rigids were designed by a Spaniard, Senor
Torres, and built by the Astra Company.  The envelope was of
trefoil shape, this being due to the interior rigging from the
suspension band; the exterior appearance is that of two lobes
side by side, overlaid by a third.  The interior rigging, which
was adopted with a view to decreasing air resistance, supports a
low-hung car from the centre of the envelope; steering is
accomplished by means of horizontal planes fixed on the envelope
at the stern, and vertical planes depending beneath the envelope,
also at the stern end.

One of the most successful of French pre-war dirigibles was a
Clement Bayard built in 1912.  In this twin propellers were
placed at the front and horizontal and vertical rudders in a
sort of box formation under the envelope at the stern.  The
envelope was stream-lined, while the car of the machine was
placed well forward with horizontal controlling planes above it
and immediately behind the propellers.  This airship, which was
named 'Dupuy de Lome,' may be ranked as about the most
successful non-rigid dirigible constructed prior to the War.

Experiments with non-rigids in Germany was mainly carried on by
Major Parseval, who produced his first vessel in 1906.  The main
feature of this airship consisted in variation in length of the
suspension cables at the will of the operator, so that the
envelope could be given an upward tilt while the car remained
horizontal in order to give the vessel greater efficiency in
climbing.  In this machine, the propeller was placed above and
forward of the car, and the controlling planes were fixed
directly to the envelope near the forward end.  A second vessel
differed from the first mainly in the matter of its larger size,
variable suspension being again employed, together with a similar
method of control.  The vessel was moderately successful, and
under Major Parseval's direction a third was constructed for
passenger carrying, with two engines of 120 horsepower, each
driving propellers of 13 feet diameter.  This was the most
successful of the early German dirigibles; it made a number of
voyages with a dozen passengers in addition to its crew, as well
as proving its value for military purposes by use as a scout
machine in manoeuvres.  Later Parsevals were constructed of
stream-line form, about 300 feet in length, and with engines
sufficiently powerful to give them speeds up to 50 miles an hour.

Major Von Gross, commander of a Balloon Battalion, produced
semi-rigid dirigibles from 1907 onward.  The second of these,
driven by two 75 horse-power Daimler motors, was capable of a
speed of 27 miles an hour; in September of 1908 she made a trip
from and back to Berlin which lasted 13 hours, in which period
she covered 176 miles with four passengers and reached a height
of 4,000 feet.  Her successor, launched in April of 1909,
carried a wireless installation, and the next to this, driven by
four motors of 75 horse-power each, reached a speed of 45 miles
an hour.  As this vessel was constructed for military purposes,
very few details either of its speed or method of construction
were made public.

Practically all these vessels were discounted by the work of
Ferdinand von Zeppelin, who set out from the first with the idea
of constructing a rigid dirigible. Beginning in 1898, he built a
balloon on an aluminium framework covered with linen and silk,
and divided into interior compartments holding linen bags which
were capable of containing nearly 400,000 cubic feet of
hydrogen.  The total length of this first Zeppelin airship was
420 feet and the diameter 38 feet.  Two cars were rigidly
attached to the envelope, each carrying a 16 horse-power motor,
driving propellers which were rigidly connected to the aluminium
framework of the balloon.  Vertical and horizontal screws were
used for lifting and forward driving and a sliding weight was
used to raise or lower the stem of the vessel out of the
horizontal in order to rise or descend without altering the load
by loss of ballast or the lift by loss of gas.

The first trial of this vessel was made in July of 1900, and was
singularly unfortunate.  The winch by which the sliding weight
was operated broke, and the balloon was so bent that the working
of the propellers was interfered with, as was the steering.  A
speed of 13 feet per second was attained, but on descending, the
airship ran against some piles and was further damaged.  Repairs
were completed by the end of September, 1900, and on a second
trial flight made on October 21st a speed of 30 feet per second
was reached.

Zeppelin was far from satisfied with the performance of this
vessel, and he therefore set about collecting funds for the
construction of a second, which was completed in 1905.  By this
time the internal combustion engine had been greatly improved,
and without any increase of weight, Zeppelin was able to instal
two motors of 85 horse-power each.  The total capacity was
367,000 cubic feet of hydrogen, carried in 16 gas bags inside
the framework, and the weight of the whole construction was 9
tons--a ton less than that of the first Zeppelin airship.  Three
vertical planes at front and rear controlled horizontal
steering, while rise and fall was controlled by horizontal
planes arranged in box form.  Accident attended the first trial
of this second airship, which took place over the Bodensee on
November 30th, 1905, 'It had been intended to tow the raft, to
which it was anchored, further from the shore against the wind. 
But the water was too low to allow the use of the raft.  The
balloon was therefore mounted on pontoons, pulled out into the
lake, and taken in tow by a motor-boat.  It was caught by a
strong wind which was blowing from the shore, and driven ahead
at such a rate that it overtook the motor-boat.  The tow rope
was therefore at once cut, but it unexpectedly formed into knots
and became entangled with the airship, pulling the front end
down into the water.  The balloon was then caught by the wind
and lifted into the air, when the propellers were set in motion. 
The front end was at this instant pointing in a downward
direction, and consequently it shot into the water, where it was
found necessary to open the valves.'[*]

[*] Hildebrandt, Airships Past and Present.

The damage done was repaired within six weeks, and the second
trial was made on January 17th, 1906.  The lifting force was too
great for the weight, and the dirigible jumped immediately to
1,500 feet.  The propellers were started, and the dirigible
brought to a lower level, when it was found possible to drive
against the wind.  The steering arrangements were found too
sensitive, and the motors were stopped, when the vessel was
carried by the wind until it was over land--it had been intended
that the trial should be completed over water.  A descent was
successfully accomplished and the dirigible was anchored for the
night, but a gale caused it so much damage that it had to be
broken up.  It had achieved a speed of 30 feet per second with
the motors developing only 36 horse-power and, gathering from
this what speed might have been accomplished with the full 170
horse-power, Zeppelin set about the construction of No. 3, with
which a number of successful voyages were made, proving the value
of the type for military purposes.

No. 4 was the most notable of the early Zeppelins, as much on
account of its disastrous end as by reason of any superior merit
in comparison with No. 3.  The main innovation consisted in
attaching a triangular keel to the under side of the envelope,
with two gaps beneath which the cars were suspended.  Two Daimler
Mercedes motors of 110 horse-power each were placed one in each
car, and the vessel carried sufficient fuel for a 60-hour cruise
with the motors running at full speed.  Each motor drove a pair
of three-bladed metal propellers rigidly attached to the
framework of the envelope and about 15 feet in diameter.  There
was a vertical rudder at the stern of the envelope and horizontal
controlling planes were fixed on the sides of the envelope.  The
best performances and the end of this dirigible were summarised
as follows by Major Squier:--

'Its best performances were two long trips performed during the
summer of 1908.  The first, on July 4th, lasted exactly 12
hours, during which time it covered a distance of 235 miles,
crossing the mountains to Lucerne and Zurich, and returning to
the balloon-house near Friedrichshafen, on Lake Constance.  The
average speed on this trip was 32 miles per hour.  On August
4th, this airship attempted a 24-hour flight, which was one of
the requirements made for its acceptance by the Government.  It
left Friedrichshafen in the morning with the intention of
following the Rhine as far as Mainz, and then returning to its
starting-point, straight across the country.  A stop of 3 hours
30 minutes was made in the afternoon of the first day on the
Rhine, to repair the engine.  On the return, a second stop was
found necessary near Stuttgart, due to difficulties with the
motors, and some loss of gas.  While anchored to the ground, a
storm arose which broke loose the anchorage, and, as the balloon
rose in the air, it exploded and took fire (due to causes which
have never been actually determined and published) and fell to
the ground, where it was completely destroyed.  On this journey,
which lasted in all 31 hours 15 minutes, the airship was in the
air 20 hours 45 minutes, and covered a total distance of 378
miles.

'The patriotism of the German nation was aroused.  Subscriptions
were immediately started, and in a short space of time a quarter
of a million pounds had been raised.  A Zeppelin Society was
formed to direct the expenditure of this fund.  Seventeen
thousand pounds has been expended in purchasing land near
Friedrichshafen; workshops were erected, and it was announced
that within one year the construction of eight airships of the
Zeppelin type would be completed.  Since the disaster to
'Zeppelin IV.' the Crown Prince of Germany made a trip in
'Zeppelin No. 3,' which had been called back into service, and
within a very few days the German Emperor visited Friedrichshafen
for the purpose of seeing the airship in flight.  He decorated
Count Zeppelin with the order of the Black Eagle.  German
patriotism and enthusiasm has gone further, and the "German
Association for an Aerial Fleet" has been organised in
sections throughout the country.  It announces its intention of
building 50 garages (hangars) for housing airships.'

By January of 1909, with well over a quarter of a million in
hand for the construction of Zeppelin airships, No. 3 was again
brought out, probably in order to maintain public enthusiasm in
respect of the possible new engine of war.  In March of that
year No. 3 made a voyage which lasted for 4 hours over and in
the vicinity of Lake Constance; it carried 26 passengers for a
distance of nearly 150 miles.

Before the end of March, Count Zeppelin determined to voyage
from Friedrichshafen to Munich, together with the crew of the
airship and four military officers.  Starting at four in the
morning and ascertaining their route from the lights of railway
stations and the ringing of bells in the towns passed over, the
journey was completed by nine o'clock, but a strong south-west
gale prevented the intended landing.  The airship was driven
before the wind until three o'clock in the afternoon, when it
landed safely near Dingolfing; by the next morning the wind had
fallen considerably and the airship returned to Munich and
landed on the parade ground as originally intended.  At about
3.30 in the afternoon, the homeward journey was begun,
Friedrichshafen being reached at about 7.30.

These trials demonstrated that sufficient progress had been made
to justify the construction of Zeppelin airships for use with
the German army.  No. 3 had been manoeuvred safely if not
successfully in half a gale of wind, and henceforth it was known
as 'SMS. Zeppelin I.,' at the bidding of the German Emperor,
while the construction of 'SMS. Zeppelin II.' was rapidly
proceeded with.  The fifth construction of Count Zeppelin's was
446 feet in length, 42 1/2 feet in diameter, and contained
530,000 cubic feet of hydrogen gas in 17 separate compartments. 
Trial flights were made on the 26th May, 1909, and a week later
she made a record voyage of 940 miles, the route being from Lake
Constance over Ulm, Nuremberg, Leipzig, Bitterfeld, Weimar,
Heilbronn, and Stuttgart, descending near Goppingen; the time
occupied in the flight was upwards of 38 hours.

In landing, the airship collided with a pear-tree, which damaged
the bows and tore open two sections of the envelope, but repairs
on the spot enabled the return journey to Friedrichshafen to be
begun 24 hours later.  In spite of the mishap the Zeppelin had
once more proved itself as a possible engine of war, and
thenceforth Germany pinned its faith to the dirigible, only
developing the aeroplane to such an extent as to keep abreast of
other nations.  By the outbreak of war, nearly 30 Zeppelins had
been constructed; considerably more than half of these were
destroyed in various ways, but the experiments carried on with
each example of the type permitted of improvements being made. 
The first fatality occurred in September, 1913, when the
fourteenth Zeppelin to be constructed, known as Naval Zeppelin
L.1, was wrecked in the North Sea by a sudden storm and her
crew of thirteen were drowned.  About three weeks after this,
Naval Zeppelin L.2, the eighteenth in order of building,
exploded in mid-air while manoeuvring over Johannisthal.  She
was carrying a crew of 25, who were all killed.

By 1912 the success of the Zeppelin type brought imitators. 
Chief among them was the Schutte-Lanz, a Mannheim firm, which
produced a rigid dirigible with a wooden framework, wire braced. 
This was not a cylinder like the Zeppelin, but reverted to the
cigar shape and contained about the same amount of gas as the
Zeppelin type.  The Schutte-Lanz was made with two gondolas
rigidly attached to the envelope in which the gas bags were
placed.  The method of construction involved greater weight than
was the case with the Zeppelin, but the second of these vessels,
built with three gondolas containing engines, and a navigating
cabin built into the hull of the airship itself, proved quite
successful as a naval scout until wrecked on the islands off the
coast of Denmark late in 1914.  The last Schutte-Lanz to be
constructed was used by the Germans for raiding England, and was
eventually brought down in flames at Cowley.



V. BRITISH AIRSHIP DESIGN

As was the case with the aeroplane, Great Britain left France
and Germany to make the running in the early days of airship
construction; the balloon section of the Royal Engineers was
compelled to confine its energies to work with balloons pure and
simple until well after the twentieth century had dawned, and
such experiments as were made in England were done by private
initiative.  As far back as 1900 Doctor Barton built an airship
at the Alexandra Palace and voyaged across London in it.  Four
years later Mr E. T. Willows of Cardiff produced the first
successful British dirigible, a semi-rigid 74 feet in length and
18 feet in diameter, engined with a 7 horse-power Peugot
twin-cylindered motor.  This drove a two-bladed propeller at the
stern for propulsion, and also actuated a pair of auxiliary
propellers at the front which could be varied in their direction
so as to control the right and left movements of the airship. 
This device was patented and the patent was taken over by the
British Government, which by 1908 found Mr Willow's work of
sufficient interest to regard it as furnishing data for
experiment at the balloon factory at Farnborough.  In 1909,
Willows steered one of his dirigibles to London from Cardiff in
a little less than ten hours, making an average speed of over 14
miles an hour.  The best speed accomplished was probably
considerably greater than this, for at intervals of a few miles,
Willows descended near the earth to ascertain his whereabouts
with the help of a megaphone.  It must be added that he carried
a compass in addition to his megaphone.  He set out for Paris in
November of 1910, reached the French coast, and landed near
Douai.  Some damage was sustained in this landing, but, after
repair, the trip to Paris was completed.

Meanwhile the Government balloon factory at Farnborough began
airship construction in 1907; Colonel Capper, R.E., and S. F.
Cody were jointly concerned in the production of a semi-rigid. 
Fifteen thicknesses of goldbeaters' skin--about the most
expensive covering obtainable--were used for the envelope, which
was 25 feet in diameter.  A slight shower of rain in which the
airship was caught led to its wreckage, owing to the absorbent
quality of the goldbeaters' skin, whereupon Capper and Cody set
to work to reproduce the airship and its defects on a larger
scale.  The first had been named 'Nulli Secundus' and the second
was named 'Nulli Secundus II.'  Punch very appropriately
suggested that the first vessel ought to have been named 'Nulli
Primus,' while a possible third should be christened 'Nulli
Tertius.'  'Nulli Secundus II.' was fitted with a 100 horse-power
engine and had an envelope of 42 feet in diameter, the
goldbeaters' skin being covered in fabric and the car being
suspended by four bands which encircled the balloon envelope. 
In October of 1907, 'Nulli Secundus II.' made a trial flight
from Farnborough to London and was anchored at the Crystal
Palace.  The wind sprung up and took the vessel away from its
mooring ropes, wrecking it after the one flight.

Stagnation followed until early in 1909, when a small airship
fitted with two 12 horse-power motors and named the 'Baby' was
turned out from the balloon factory.  This was almost
egg-shaped, the blunt end being forward, and three inflated fins
being placed at the tail as control members.  A long car with
rudder and elevator at its rear-end carried the engines and
crew; the 'Baby' made some fairly successful flights and gave a
good deal of useful data for the construction of later vessels.

Next to this was 'Army Airship 2A 'launched early in 1910 and
larger, longer, and narrower in design than the Baby.  The
engine was an 80 horse-power Green motor which drove two pairs
of propellers; small inflated control members were fitted at the
stern end of the envelope, which was 154 feet in length.  The
suspended car was 84 feet long, carrying both engines and crew,
and the Willows idea of swivelling propellers for governing the
direction was used in this vessel.  In June of that year a new,
small-type dirigible, the 'Beta,' was produced, driven by a 30
horse-power Green engine with which she flew over 3,000 miles. 
She was the most successful British dirigible constructed up to
that time, and her successor, the 'Gamma,' was built on similar
lines.  The 'Gamma' was a larger vessel, however, produced in
1912, with flat, controlling fins and rudder at the rear end of
the envelope, and with the conventional long car suspended at
some distance beneath the gas bag.  By this time, the mooring
mast, carrying a cap of which the concave side fitted over the
convex nose of the airship, had been originated.  The cap was
swivelled, and, when attached to it, an airship was held nose on
to the wind, thus reducing by more than half the dangers
attendant on mooring dirigibles in the open.

Private subscription under the auspices of the Morning Post got
together sufficient funds in 1910 for the purchase of a Lebaudy
airship, which was built in France, flown across the Channel, and
presented to the Army Airship Fleet.  This dirigible was 337 feet
long, and was driven by two 135 horse-power Panhard motors, each
of which actuated two propellers.  The journey from Moisson to
Aldershot was completed at a speed of 36 miles an hour, but the
airship was damaged while being towed into its shed.  On May of
the following year, the Lebaudy was brought out for a flight,
but, in landing, the guide rope fouled in trees and sheds and
brought the airship broadside on to the wind; she was driven into
some trees and wrecked to such an exteent that rebuilding was
considered an impossibility.  A Clement Bayard, bought by the
army airship section, became scrap after even less flying than
had been accomplished by the Lebaudy.

In April of 1910,, the Admiralty determined on a naval air
service, and set about the production of rigid airships which
should be able to compete with Zeppelins as naval scouts. The
construction was entrusted to Vickers, Ltd.,  who set about the
task at their Barrow works and built something which, when tested
after a year's work, was found incapable of lifting its own
weight.  This defect was remedied by a series of alterations, and
meanwhile the unofficial title of 'Mayfly' was given to the
vessel.

Taken over by the Admiralty before she had passed any flying
tests, the 'Mayfly' was brought out on September 24th, 1911, for
a trial trip, being towed out from her shed by a tug.  When ha]f
out from the shed, the envelope was caught by a light
cross-wind, and, in spite of the pull from the tug, the great
fabric broke in half, nearly drowning the crew, who had to dive
in order to get clear of the wreckage.

There was considerable similarity in form, though not in
performance, between the Mayfly and the prewar Zeppelin.  The
former was 510 feet in length, cylindrical in form, with a
diameter of 48 feet, and divided into 19 gas-bag compartments. 
The motive power consisted of two 200 horse-power Wolseley
engines.  After its failure, the Naval Air Service bought an
Astra-Torres airship from France and a Parseval from Germany,
both of which proved very useful in the early days of the War,
doing patrol work over the Channel before the Blimps came into
being.

Early in 1915 the 'Blimp' or 'S.S.' type of coastal airship
was evolved in response to the demand for a vessel which could
be turned out quickly and in quantities.  There was urgent
demand, voiced by Lord Fisher, for a type of vessel capable of
maintaining anti-submarine patrol off the British coasts, and
the first S.S. airships were made by combining a gasbag with
the most available type of aeroplane fuselage and engine, and
fitting steering gear.  The 'Blimp' consisted of a B.E. fuselage
with engine and geared-down propeller, and seating for pilot and
observer, attached to an envelope about 150 feet in length. 
With a speed of between 35 and 40 miles an hour, the 'Blimp' had
a cruising capacity of about ten hours; it was fitted with
wireless set, camera, machine-gun, and bombs, and for submarine
spotting and patrol work generally it proved invaluable, though
owing to low engine power and comparatively small size, its uses
were restricted to reasonably fair weather.  For work farther out
at sea and in all weathers, airships known as the coast patrol
type, and more commonly as 'coastals,' were built, and later the
'N.S.' or North Sea type, still larger and more weather-worthy,
followed.  By the time the last year of the War came, Britain
led the world in the design of non-rigid and semi-rigid
dirigibles.  The 'S.S.' or 'Blimp' had been improved to a speed
of 50 miles an hour, carrying a crew of three, and the endurance
record for the type was 18 1/2 hours, while one of them had
reached a height of 10,000 feet.  The North Sea type of
non-rigid was capable of travelling over 20 hours at full speed,
or forty hours at cruising speed, and the number of non-rigids
belonging to the British Navy exceeded that of any other
country.

It was owing to the incapacity--apparent or real-- of the
British military or naval designers to produce a satisfactory
rigid airship that the 'N.S.' airship was evolved.  The first of
this type was produced in 1916, and on her trials she was voted
an unqualified success, in consequence of which the building of
several more was pushed on.  The envelope, of 360,000 cubic feet
capacity, was made on the Astra-Torres principle of three lobes,
giving a trefoil section.  The ship carried four fins, to three
of which the elevator and rudder flaps were attached; petrol
tanks were placed inside the envelope, under which was rigged a
long covered-in car, built up of a light steel tubular framework
35 feet in length.  The forward portion was covered with
duralumin sheeting, an aluminium alloy which, unlike aluminium
itself, is not affected by the action of sea air and water, and
the remainder with fabric laced to the framework.  Windows and
port-holes were provided to give light to the crew, and the
controls and navigating instruments were placed forward, with the
sleeping accommodation aft.  The engines were mounted in a power
unit structure, separate from the car and connected by wooden
gang ways supported by wire cables.  A complete electrical
installation of two dynamos and batteries for lights, signalling
lamps, wireless, telephones, etc., was carried, and the motive
power consisted of either two 250 horse-power Rolls-Royce engines
or two 240 horse-power Fiat engines.  The principal dimensions of
this type are length 262 feet, horizontal diameter 56 feet 9
inches, vertical diameter 69 feet 3 inches.  The gross lift is
24,300 lbs. and the disposable lift without crew, petrol, oil,
and ballast 8,500 lbs.  The normal crew carried for patrol work
was ten officers and men.  This type holds the record of 101
hours continuous flight on patrol duty.

In the matter of rigid design it was not until 1913 that the
British Admiralty got over the fact that the 'Mayfly' would not,
and decided on a further attempt at the construction of a rigid
dirigible.  The contract for this was signed in March of 1914;
work was suspended in the following February and begun again in
July, 1915, but it was not until January of 1917 that the
ship was finished, while her trials were not completed until
March of 1917, when she was taken over by the Admiralty.  The
details of the construction and trial of this vessel, known as
'No. 9,' go to show that she did not quite fill the contract
requirements in respect of disposable lift until a number of
alterations had been made.  The contract specified that a speed
of at least 45 miles per hour was to be attained at full engine
power, while a minimum disposable lift of 5 tons was to be
available for movable weights, and the airship was to be capable
of rising to a height of 2,000 feet.  Driven by four Wolseley
Maybach engines of 180 horse-power each, the lift of the vessel
was not sufficient, so it was decided to remove the two engines
in the after car and replace them by a single engine of 250
horsepower.  With this the vessel reached the contract speed of
45 miles per hour with a cruising radius of 18 hours, equivalent
to 800 miles when the engines were running at full speed.  The
vessel served admirably as a training airship, for, by the time
she was completed, the No. 23 class of rigid airship had come to
being, and thus No. 9 was already out of date.

Three of the 23 class were completed by the end of 1917; it was
stipulated that they should be built with a speed of at least 55
miles per hour, a minimum disposable lift of 8 tons, and a
capability of rising at an average rate of not less than 1,000
feet per minute to a height of 3,000 feet. The motive power
consisted of four 250 horse-power Rolls-Royce engines, one in
each of the forward and after cars and two in a centre car. 
Four-bladed propellers were used throughout the ship.

A 23X type followed on the 23 class, but by the time two ships
had been completed, this was practically obsolete.  The No. 31
class followed the 23X; it was built on Schutte-Lanz lines, 615
feet in length, 66 feet diameter, and a million and a half cubic
feet capacity.  The hull was similar to the later types of
Zeppelin in shape, with a tapering stern and a bluff, rounded
bow.  Five cars each carrying a 250 horse-power Rolls-Royce
engine, driving a single fixed propeller, were fitted, and on
her trials R.31 performed well, especially in the matter of
speed.  But the experiment of constructing in wood in the
Schutte-Lanz way adopted with this vessel resulted in failure
eventually, and the type was abandoned.

Meanwhile, Germany had been pushing forward Zeppelin design and
straining every nerve in the improvement of rigid dirigible
construction, until L.33 was evolved; she was generally known as
a super-Zeppelin, and on September 24th, 1916, six weeks
after her launching, she was damaged by gun-fire in a raid over
London, being eventually compelled to come to earth at Little
Wigborough in Essex.  The crew gave themselves up after having
set fire to the ship, and though the fabric was totally
destroyed, the structure of the hull remained intact, so that
just as Germany was able to evolve the Gotha bomber from the
HandleyPage delivered at Lille, British naval constructors were
able to evolve the R.33 type of airship from the Zeppelin
framework delivered at Little Wigborough.  Two vessels, R.33 and
R.34, were laid down for completion; three others were also put
down for construction, but, while R.33 and R.34 were built
almost entirely from the data gathered from the wrecked L.33,
the three later vessels embody more modern design, including a
number of improvements, and more especially greater disposable
lift.  It has been commented that while the British authorities
were building R.33 and R.34, Germany constructed 30 Zeppelins on
4 slips, for which reason it may be reckoned a matter for
congratulation that the rigid airship did not decide the fate of
the War.  The following particulars of construction  of the R.33
and R.34 types are as given by Major Whale in his survey of
British Airships:--

'In all its main features the hull structure of R.33 and R.34
follows the design of the wrecked German Zeppelin airship L.33. 
'The hull follows more nearly a true stream-line shape than in
the previous ships constructed of duralumin, in which a greater
proportion of the greater length was parallel-sided.  The
Germans adopted this new shape from the Schutte-Lanz design and
have not departed from this practice.  This consists of a short,
parallel body with a long, rounded bow and a long tapering stem
culminating in a point.  The overall length of the ship is 643
feet with a diameter of 79 feet and an extreme height of 92
feet.

'The type of girders in this class has been much altered from
those in previous ships.  The hull is fitted with an internal
triangular keel throughout practically the entire length.  This
forms the main corridor of the ship, and is fitted with a
footway down the centre for its entire length. It contains water
ballast and petrol tanks, bomb storage and crew accommodation,
and the various control wires, petrol pipes, and electric leads
are carried along the lower part.

'Throughout this internal corridor runs a bridge girder, from
which the petrol and water ballast tanks are supported.  These
tanks are so arranged that they can be dropped clear of the
ship.  Amidships is the cabin space with sufficient room for a
crew of twenty-five.  Hammocks can be swung from the bridge
girder before mentioned.

'In accordance with the latest Zeppelin practice, monoplane
rudders and elevators are fitted to the horizontal and vertical
fins.

'The ship is supported in the air by nineteen gas bags, which
give a total capacity of approximately two million cubic feet of
gas.  The gross lift works out at approximately 59 1/2 tons, of
which the total fixed weight is 33 tons, giving a disposable
lift of 26 1/2 tons.

'The arrangement of cars is as follows:  At the forward end the
control car is slung, which contains all navigating instruments
and the various controls.  Adjoining this is the wireless cabin,
which is also fitted for wireless telephony.  Immediately aft of
this is the forward power car containing one engine, which gives
the appearance that the whole is one large car.

'Amidships are two wing cars, each containing a single engine. 
These are small and just accommodate the engines with sufficient
room for mechanics to attend to them.  Further aft is another
larger car which contains an auxiliary control position and two
engines.

'It will thus be seen that five engines are installed in the
ship; these are all of the same type and horsepower, namely, 250
horse-power Sunbeam.  R.33 was constructed by Messrs Armstrong,
Whitworth, Ltd.; while her sister ship R.34 was built by Messrs
Beardmore on the Clyde.'

Of the two vessels, R.34 appeared rather more airworthy than her
sister ship; the lift of the ship justified the carrying of a
greater quantity of fuel than had been provided for, and, as she
was considered suitable for making a Transatlantic crossing,
extra petrol tanks were fitted in the hull and a new type of
outer cover was fitted with a view to her making the Atlantic
crossing.  She made a 21-hour cruise over the North of England
and the South of Scotland at the  end of May, 1919, and
subsequently went for a longer cruise over Denmark, the Baltic,
and the north coast of Germany, remaining in the air for 56 hours
in spite of very bad weather conditions.  Finally, July 2nd was
selected as the starting date for the cross Atlantic flight; the
vessel was commanded by Major G. H. Scott, A.F.C., with Captain
G. S. Greenland as first officer, Second-Lieut. H. F. Luck as
second officer, and Lieut. J. D. Shotter as engineer officer. 
There were also on board Brig.-Gen. E. P. Maitland, representing
the Air Ministry, Major J. E. M. Pritchard, representing the
Admiralty, and Lieut.-Col. W. H. Hemsley of the Army Aviation
Department.  In addition to eight tons of petrol, R.34 carried a
total number of 30 persons from East Fortune to Long Island, N.Y.

There being no shed in America capable of accommodating the
airship, she had to be moored in the open for refilling with fuel
and gas, and to make the return journey almost immediately.

Brig.-Gen. Maitland's account of the flight, in itself a record
as interesting as valuable, divides the outward journey into two
main stages, the first from East Fortune to Trinity Bay,
Newfoundland, a distance of 2,050 sea miles, and the second and
more difficult stage to Mineola Field, Long Island, 1,080 sea
miles.  An easy journey was experienced until Newfoundland was
reached, but then storms and electrical disturbances rendered it
necessary to alter the course, in consequence of which petrol
began to run short.  Head winds rendered the shortage still more
acute, and on Saturday, July 5th, a wireless signal was sent out
asking for destroyers to stand by to tow.  However, after an
anxious night, R.33 landed safely at Mineola Field at 9.55 a.m.
on July 6th, having accomplished the journey in 108 hours 12
minutes.

She remained at Mineola until midnight of July 9th, when,
although it had been intended that a start should be made by
daylight for the benefit of New York spectators, an approaching
storm caused preparations to be advanced for immediate
departure.  She set out at 5.57 a.m. by British summer time,
and flew over New York in the full glare of hundreds of
searchlights before heading out over the Atlantic.  A following
wind assisted the return voyage, and on July 13th, at 7.57 a.m.,
R.34 anchored at Pulham, Norfolk, having made the return journey
in 75 hours 3 minutes, and proved the suitability of the
dirigible for Transatlantic commercial work.  R.80, launched on
July 19th, 1920, afforded further proof, if this were needed.

It is to be noted that nearly all the disasters to airships have
been caused by launching and landing-- the type is safe enough
in the air, under its own power, but its bulk renders it
unwieldy for ground handling.  The German system of handling
Zeppelins in and out of their sheds is, so far, the best
devised:  this consists of heavy trucks running on rails through
the sheds and out at either end; on descending, the trucks are
run out, and the airship is securely attached to them outside
the shed; the trucks are then run back into the shed, taking the
airship with them, and preventing any possibility of the wind
driving the envelope against the side of the shed before it is
safely housed; the reverse process is adopted in launching,
which is thus rendered as simple as it is safe.



VI. THE AIRSHIP COMMERCIALLY

Prior to the war period, between the years 1910 and 1914, a
German undertaking called the Deutsche Luftfahrt Actien
Gesellschaft conducted a commercial Zeppelin service in which
four airships known as the Sachsan, Hansa, Victoria Louise, and
Schwaben were used.  During the four years of its work, the
company carried over 17,000 passengers, and over 100,000 miles
were flown without incurring one fatality and with only minor
and unavoidable accidents to the vessels composing the service. 
Although a number of English notabilities made voyages in these
airships, the success of this only experiment in commercial
aerostation seems to have been forgotten since the war.  There
was beyond doubt a military aim in this apparently peaceful use
of Zeppelin airships; it is past question now that all Germany's
mechanical development in respect of land sea, and air transport
in the years immediately preceding the war, was accomplished
with the ulterior aim of military conquest, but, at the same
time, the running of this service afforded proof of the
possibility of establishing a dirigible service for peaceful
ends, and afforded proof too, of the value of the dirigible as a
vessel of purely commercial utility.

In considering the possibility of a commercial dirigible
service, it is necessary always to bear in mind the
disadvantages of first cost and upkeep as compared with the
aeroplane.  The building of a modern rigid is an exceedingly
costly undertaking, and the provision of an efficient supply of
hydrogen gas to keep its compartments filled is a very large
item in upkeep of which the heavier-than-air machine goes free. 
Yet the future of commercial aeronautics so far would seem to
lie with the dirigible where very long voyages are in question. 
No matter how the aeroplane may be improved, the possibility of
engine failure always remains as a danger for work over water.
In seaplane or flying boat form, the danger is still present in
a rough sea, though in the American Transatlantic flight, N.C.3,
taxi-ing 300 miles to the Azores after having fallen to the
water, proved that this danger is not so acute as is generally
assumed.  Yet the multiple-engined rigid, as R.34 showed on her
return voyage, may have part of her power plant put out of
action altogether and still complete her voyage very
successfully, which, in the case of mail carrying and services
run strictly to time, gives her an enormous advantage over the
heavier-than-air machine.

'For commercial purposes,' General Sykes has remarked, 'the
airship is eminently adapted for long distance journeys
involving non-stop flights.  It has this inherent advantage over
the aeroplane, that while there appears to be a limit to the
range of the aeroplane as at present constructed, there is
practically no limit whatever to that of the airship, as this
can be overcome by merely increasing the size.  It thus appears
that for such journeys as crossing the Atlantic, or crossing the
Pacific from the west coast of America to Australia or Japan,
the airship will be peculiarly suitable.  It having been
conceded that the scope of the airship is long distance travel,
the only type which need be considered for this purpose is the
rigid.  The rigid airship is still in an embryonic state, but
sufficient has already been accomplished in this country, and
more particularly in Germany, to show that with increased
capacity there is no reason why, within a few years' time,
airships should not be built capable of completing the circuit
of the globe and of conveying sufficient passengers and
merchandise to render such an undertaking a paying proposition.'

The British R.38 class, embodying the latest improvements in
airship design outside Germany, gives a gross lift per airship
of 85 tons and a net lift of about 45 tons.  The capacity of
the gas bags is about two and three-quarter million cubic feet,
and, travelling at the rate of 45 miles per hour, the cruising
range of the vessel is estimated at 8.8 days.  Six engines, each
of 350 horse-power, admit of an extreme speed of 70 miles per
hour if necessary.

The last word in German design is exemplified in the rigids L.70
and L.71, together with the commercial airship 'Bodensee.'
Previous to the construction of these, the L.65 type is
noteworthy as being the first Zeppelin in which direct drive of
the propeller was introduced, together with an improved and
lighter type of car.  L.70 built in 1918 and destroyed by the
British naval forces, had a speed of about 75 miles per hour;
L.71 had a maximum speed of 72 miles per hour, a gas bag
capacity of 2,420,000 cubic feet, and a length of 743 feet,
while the total lift was 73 tons.  Progress in design is best
shown by the progress in useful load; in the L.70 and L.71
class, this has been increased to 58.3 per cent, while in the
Bodensee it was ever higher.

As was shown in R.34's American flight, the main problem in
connection with the commercial use of dirigibles is that of
mooring in the open.  The nearest to a solution of this problem,
so far, consists in the mast carrying a swivelling cap; this has
been tried in the British service with a non-rigid airship,
which was attached to a mast in open country in a gale of 52
miles an hour without the slightest damage to the airship.  In
its commercial form, the mast would probably take the form of a
tower, at the top of which the cap would revolve so that the
airship should always face the wind, the tower being used for
embarkation and disembarkation of passengers and the provision
of fuel and gas.  Such a system would render sheds unnecessary
except in case of repairs, and would enormously decrease the
establishment charges of any commercial airship.

All this, however, is hypothetical.  Remains the airship of
to-day, developed far beyond the promise of five years ago,
capable, as has been proved by its achievements both in Britain
and in Germany, of undertaking practically any given voyage with
success.



VII. KITE BALLOONS

As far back as the period of the Napoleonic wars, the balloon
was given a place in warfare, but up to the Franco-Prussian
Prussian War of 1870-71 its use was intermittent.  The Federal
forces made use of balloons to a small extent in the American
Civil War; they came to great prominence in the siege of Paris,
carrying out upwards of three million letters and sundry carrier
pigeons which took back messages into the besieged city.
Meanwhile, as captive balloons, the German and other armies used
them for observation and the direction of artillery fire.  In
this work the ordinary spherical balloon was at a grave
disadvantage; if a gust of wind struck it, the balloon was blown
downward and down wind, generally twirling in the air and
upsetting any calculations and estimates that might be made by
the observers, while in a wind of 25 miles an hour it could not
rise at all.  The rotatory movement caused by wind was stopped
by an experimenter in the Russo-Japanese war, who fixed to the
captive observation balloons a fin which acted as a rudder.  This
did not stop the balloon from being blown downward and away from
its mooring station, but this tendency was overcome by a
modification designed in Germany by the Parseval-Siegsfield
Company, which originated what has since become familiar as the
'Sausage' or kite balloon.  This is so arranged that the forward
end is tilted up into the wind, and the underside of the gas
bag, acting as a plane, gives the balloon a lifting tendency in
a wind, thus counteracting the tendency of the wind to blow it
downward and away from its mooring station.  Smaller bags are
fitted at the lower and rear end of the balloon with openings
that face into the wind; these are thus kept inflated, and they
serve the purpose of a rudder, keeping the kite balloon steady
in the air.

Various types of kite balloon have been introduced; the original
German Parseval-Siegsfield had a single air bag at the stern
end, which was modified to two, three, or more lobes in later
varieties, while an American experimental design attempted to do
away with the attached lobes altogether by stringing out a
series of small air bags, kite fashion, in rear of the main
envelope.  At the beginning of the War, Germany alone had kite
balloons, for the authorities of the Allied armies con-sidered
that the bulk of such a vessel rendered it too conspicuous a
mark to permit of its being serviceable.  The Belgian arm alone
possessed two which, on being put into service, were found
extremely useful.  The French followed by constructing kite
balloons at Chalais Meudon, and then, after some months of
hostilities and with the example of the Royal Naval Air Service
to encourage them, the British military authorities finally took
up the construction and use of kite balloons for
artillery-spotting and general observation purposes.  Although
many were brought down by gun-fire, their uses far outweighed
their disadvantages, and toward the end of the War, hardly a
mile of front was without its 'Sausage.'

For naval work, kite balloons were carried in a specially
constructed hold in the forepart of certain vessels; when
required for use, the covering of the hold was removed, the
kite balloon inflated and released to the required height by
means of winches as in the case of the land work.  The
perfecting of the 'Coastal' and N.S. types of airship, together
with the extension of wireless telephony between airship and
cruiser or other warship, in all probability will render the use
of the kite balloon unnecessary in connection with naval
scouting.  But, during the War, neither wireless telephony nor
naval airships had developed sufficiently to render the Navy
independent of any means that might come to hand, and the
fitting of kite balloons in this fashion filled a need of the
times.

A necessary accessory of the kite balloon is the parachute,
which has a long history.  Da Vinci and Veranzio appear to have
been the first exponents, the first in the theory and the latter
in the practice of parachuting.  Montgolfier experimented at
Annonay before he constructed his first hot air-balloon, and in
1783 a certain Lenormand dropped from a tree in a parachute. 
Blanchard the balloonist made a spectacle of parachuting, and
made it a financial success; Cocking, in 1836, attempted to use
an inverted form of parachute; taken up to a height of 3,000
feet, he was cut adrift, when the framework of the parachute
collapsed and Cocking was killed.

The rate of fall is slow in parachuting to the ground.  Frau
Poitevin, making a descent from a height of 6,000 feet, took 45
minutes to reach the ground, and, when she alighted, her
husband, who had taken her up, had nearly got his balloon packed
up.  Robertson, another parachutist is said to have descended
from a height of 10,000 feet in 35 minutes, or at a rate of
nearly 5 feet per second.  During the War Brigadier-General
Maitland made a parachute descent from a height of 10,000 feet,
the time taken being about 20 minutes.

The parachute was developed considerably during the War period,
the main requirement, that of certainty in opening, being
considerably developed.  Considered a necessary accessory for
kite balloons, the parachute was also partially adopted for use
with aeroplanes in the later War period, when it was contended
that if a machine were shot down in flames, its occupants would
be given a far better chance of escape if they had parachutes. 
Various trials were made to demonstrate the extreme efficiency
of the parachute in modern form, one of them being a descent
from the upper ways of the Tower Bridge to the waters of the
Thames, in which short distance the 'Guardian Angel' type of
parachute opened and cushioned the descent for its user.

For dirigibles, balloons, and kite balloons the parachute is
an essential.  It would seem to be equally essential in the case
of heavier-than-air machines, but this point is still debated. 
Certainly it affords the occupant of a falling aeroplane a
chance, no matter how slender, of reaching the ground in safety,
and, for that reason, it would seem to have a place in aviation
as well as in aerostation.



PART IV. ENGINE DEVELOPMENT

I. THE VERTICAL TYPE

The balloon was but a year old when the brothers Robert, in 1784
attempted propulsion of an aerial vehicle by hand-power,
and succeeded, to a certain extent, since they were able to make
progress when there was only a slight wind to counteract their
work.  But, as may be easily understood, the manual power
provided gave but a very slow speed, and in any wind it all the
would-be airship became an uncontrolled balloon.

Henson and Stringfellow, with their light steam engines, were
first to attempt conquest of the problem of mechanical
propulsion in the air; their work in this direction is so fully
linked up with their constructed models that it has been
outlined in the section dealing with the development of the
aeroplane.  But, very shortly after these two began, there came
into the field a Monsieur Henri Giffard, who first achieved
success in the propulsion by mechanical means of dirigible
balloons, for his was the first airship to fly against the wind. 
He employed a small steam-engine developing about 3 horse-power
and weighing 350 lbs. with boiler, fitting the whole in a car
suspended from the gas-bag of his dirigible.  The propeller which
this engine worked was 11 feet in diameter, and the inventor, who
made several flights, obtained a speed of 6 miles an hour against
a slight wind.  The power was not sufficient to render the
invention practicable, as the dirigible could only be used in
calm weather, but Giffard was sufficiently encouraged by his
results to get out plans for immense dirigibles, which through
lack of funds he was unable to construct.  When, later, his
invention of the steam-injector gave him the means he desired, he
became blind, and in 1882 died, having built but the one famous
dirigible.

This appears to have been the only instance of a steam engine
being fitted to a dirigible; the inherent disadvantage of this
form of motive power is that a boiler to generate the steam must
be carried, and this, together with the weight of water and
fuel, renders the steam engine uneconomical in relation to the
lift either of plane or gas-bag.  Again, even if the weight
could be brought down to a reasonable amount, the attention
required by steam plant renders it undesirable as a motive power
for aircraft when compared with the internal combustion engine.

Maxim, in Artificial and Natural Flight, details the engine
which he constructed for use with his giant experimental flying
machine, and his description is worthy of reproduction since it
is that of the only steam engine besides Giffard's, and apart
from those used for the propulsion of models, designed for
driving an aeroplane.  'In 1889,' Maxim says, 'I had my
attention drawn to some very thin, strong, and comparatively
cheap tubes which were being made in France, and it was only
after I had seen these tubes that I seriously considered the
question of making a flying machine.  I obtained a large
quantity of them and found that they were very light, that they
would stand enormously high pressures, and generate a very large
quantity of steam.  Upon going into a mathematical calculation of
the whole subject, I found that it would be possible to make a
machine on the aeroplane system, driven by a steam engine, which
would be sufficiently strong to lift itself into the air.  I
first made drawings of a steam engine, and a pair of these
engines was afterwards made.  These engines are constructed, for
the most part, of a very high grade of cast steel, the cylinders
being only 3/32 of an inch thick, the crank shafts hollow, and
every part as strong and light as possible.  They are compound,
each having a high-pressure piston with an area of 20 square
inches, a low-pressure piston of 50.26 square inches, and a
common stroke of 1 foot.  When first finished they were found to
weigh 300 lbs.  each; but after putting on the oil cups, felting,
painting, and making some slight alterations, the weight was
brought up to 320 lbs. each, or a total of 640 lbs. for the
two engines, which have since developed 362 horsepower with a
steam pressure of 320 lbs. per square inch.'

The result is remarkable, being less than 2 lbs. weight per
horse-power, especially when one considers the state of
development to which the steam engine had attained at the time
these experiments were made.  The fining down of the internal
combustion engine, which has done so much to solve the problems
of power in relation to weight for use with aircraft, had not
then been begun, and Maxim had nothing to guide him, so far as
work on the part of his predecessors was concerned, save the
experimental engines of Stringfellow, which, being constructed
on so small a scale in comparison with his own, afforded little
guidance.  Concerning the factor of power, he says:  'When first
designing this engine, I did not know how much power I might
require from it.  I thought that in some cases it might be
necessary to allow the high-pressure steam to enter the
low-pressure cylinder direct, but as this would involve a
considerable loss, I constructed a species of injector.  This
injector may be so adjusted (hat when the steam in the boiler
rises above a certain predetermined point, say 300 lbs., to the
square inch, it opens a valve and escapes past the high-pressure
cylinder instead of blowing off at the safety valve.  In
escaping through this valve, a fall of about 200 lbs. pressure
per square inch is made to do work on the surrounding steam and
drive it forward in the pipe, producing a pressure on the
low-pressure piston considerably higher than the back-pressure
on the high-pressure piston.  In this way a portion of the work
which would otherwise be lost is utilised, and it is possible,
with an unlimited supply of steam, to cause the engines to
develop an enormous amount of power.'

With regard to boilers, Maxim writes,

'The first boiler which I made was constructed something on the
Herreshof principle, but instead of having one simple pipe in
one very long coil, I used a series of very small and light
pipes, connected in such a manner that there was a rapid
circulation through the whole--the tubes increasing in size and
number as the steam was generated.  I intended that there should
be a pressure of about 100 lbs. more on the feed water end of
the series than on the steam end, and I believed that this
difference in pressure would be sufficient to ensure direct and
positive circulation through every tube in the series.  The first
boiler was exceedingly light, but the workmanship, as far as
putting the tubes together was concerned, was very bad, and it
was found impossible to so adjust the supply of water as to make
dry steam without overheating and destroying the tubes.

'Before making another boiler I obtained a quantity of copper
tubes, about 8 feet long, 3/8 inch external diameter, and 1/50 of
an inch thick.  I subjected about 100 of these tubes to an
internal pressure of 1 ton per square inch of cold kerosene oil,
and as none of them leaked I did not test any more, but
commenced my experiments by placing some of them in a white-hot
petroleum fire.  I found that I could evaporate as much as 26
1/2 lbs. of water per square foot of heating surface per hour,
and that with a forced circulation, although the quantity of
water passing was very small but positive, there was no danger
of overheating.  I conducted many experiments with a pressure of
over 400 lbs. per square inch, but none of the tubes failed. 
I then mounted a single tube in a white-hot furnace, also with a
water circulation, and found that it only burst under steam at a
pressure of 1,650 lbs. per square inch.  A large boiler,
having about 800 square feet of heating surface, including the
feed-water heater, was then constructed.  This boiler is about 4
1/2 feet wide at the bottom, 8 feet long and 6 feet high.  It
weighs, with the casing, the dome, and the smoke stack and
connections, a little less than 1,000 lbs.  The water first
passes through a system of small tubes--1/4 inch in diameter and
1/60 inch thick--which were placed at the top of the boiler and
immediately over the large tubes.... This feed-water heater is
found to be very effective.  It utilises the heat of the
products of combustion after they have passed through the boiler
proper and greatly reduces their temperature, while the
feed-water enters the boiler at a temperature of about 250 F.  A
forced circulation is maintained in the boiler, the feed-water
entering through a spring valve, the spring valve being adjusted
in such a manner that the pressure on the water is always 30
lbs. per square inch in excess of the boiler pressure.  This
fall of 30 lbs. in pressure acts upon the surrounding hot water
which has already passed through the tubes, and drives it down
through a vertical outside tube, thus ensuring a positive and
rapid circulation through all the tubes.  This apparatus is
found to act extremely well.'

Thus Maxim, who with this engine as power for his large
aeroplane achieved free flight once, as a matter of experiment,
though for what distance or time the machine was actually off
the ground is matter for debate, since it only got free by
tearing up the rails which were to have held it down in the
experiment.  Here, however, was a steam engine which was
practicable for use in the air, obviously, and only the rapid
success of the internal combustion engine prevented the
steam-producing type from being developed toward perfection.

The first designers of internal combustion engines, knowing
nothing of the petrol of these days, constructed their examples
with a view to using gas as fuel.  As far back as 1872 Herr Paul
Haenlein obtained a speed of about 10 miles an hour with a
balloon propelled by an internal combustion engine, of which the
fuel was gas obtained from the balloon itself.  The engine in
this case was of the Lenoir type, developing some 6 horse-power,
and, obviously, Haenlein's flights were purely experimental and
of short duration, since he used the gas that sustained him and
decreased the lifting power of his balloon with every stroke of
the piston of his engine.  No further progress appears to have
been made with the gas-consuming type of internal combustion
engine for work with aircraft; this type has the disadvantage of
requiring either a gas-producer or a large storage capacity for
the gas, either of which makes the total weight of the power
plant much greater than that of a petrol engine.  The latter type
also requires less attention when working, and the fuel is more
convenient both for carrying and in the matter of carburation.

The first airship propelled by the present-day type of internal
combustion engine was constructed by Baumgarten and Wolfert in
1879 at Leipzig, the engine being made by Daimler with a view to
working on benzine--petrol as a fuel had not then come to its
own.  The construction of this engine is interesting since it was
one of the first of Daimler's make, and it was the development
brought about by the experimental series of which this engine
was one that led to the success of the motor-car in very few
years, incidentally leading to that fining down of the internal
combustion engine which has facilitated the development of the
aeroplane with such remarkable rapidity.  Owing to the faulty
construction of the airship no useful information was obtained
from Daimler's pioneer installation, as the vessel got out of
control immediately after it was first launched for flight, and
was wrecked.  Subsequent attempts at mechanically-propelled
flight by Wolfert ended, in 1897, in the balloon being set on
fire by an explosion of benzine vapour, resulting in the death
of both the aeronauts.

Daimler, from 1882 onward, devoted his attention to the
perfecting of the small, high-speed petrol engine for motor-car
work, and owing to his efforts, together with those of other
pioneer engine-builders, the motorcar was made a success.  In a
few years the weight of this type of engine was reduced from near
on a hundred pounds per horse-power to less than a tenth of that
weight, but considerable further improvement had to be made
before an engine suitable for use with aircraft was evolved.

The increase in power of the engines fitted to airships has made
steady progress from the outset; Haenlein's engine developed
about 6 horse-power; the Santos-Dumont airship of 1898 was
propelled by a motor of 4 horse-power; in 1902 the Lebaudy
airship was fitted with an engine of 40 horse-power, while, in
1910, the Lebaudy brothers fitted an engine of nearly 300
horsepower to the airship they were then constructing--1,400
horse-power was common in the airships of the War period, and
the later British rigids developed yet more.

Before passing on to consideration of the petrol-driven type of
engine, it is necessary to accord brief mention to the dirigible
constructed in 1884 by Gaston and Albert Tissandier, who at
Grenelle, France, achieved a directed flight in a wind of 8
miles an hour, obtaining their power for the propeller from 1 1/3
horse-power Siemens electric motor, which weighed 121 lbs. and
took its current from a bichromate battery weighing 496 lbs.  A
two-bladed propeller, 9 feet in diameter, was used, and the
horse-power output was estimated to have run up to 1 1/2 as the
dirigible successfully described a semicircle in a wind of 8
miles an hour, subsequently making headway transversely to a wind
of 7 miles an hour.  The dirigible with which this motor was used
was of the conventional pointed-end type, with a length of 92
feet, diameter of 30 feet, and capacity of 37,440 cubic feet of
gas.  Commandant Renard, of the French army balloon corps,
followed up Tissandier's attempt in the next year--1885--making a
trip from Chalais-Meudon to Paris and returning to the point of
departure quite successfully.  In this case the motive power was
derived from an electric plant of the type used by the
Tissandiers, weighing altogether 1,174 lbs., and developing 9
horsepower.  A speed of 14 miles an hour was attained with this
dirigible, which had a length of 165 feet, diameter of 27 feet,
and capacity of 65,836 cubic feet of gas.

Reverting to the petrol-fed type again, it is to be noted that
Santos-Dumont was practically the first to develop the use of
the ordinary automobile engine for air work--his work is of such
importance that it has been considered best to treat of it as
one whole, and details of the power plants are included in the
account of his experiments.  Coming to the Lebaudy brothers and
their work, their engine of 1902 was a 40 horse-power Daimler,
four-cylindered; it was virtually a large edition of the Daimler
car engine, the arrangement of the various details being on the
lines usually adopted for the standard Daimler type of that
period.  The cylinders were fully water-jacketed, and no special
attempt toward securing lightness for air work appears to have
been made.

The fining down of detail that brought weight to such limits as
would fit the engine for work with heavier-than-air craft
appears to have waited for the brothers Wright.  Toward the end
of 1903 they fitted to their first practicable flying machine the
engine which made the historic first aeroplane flight; this
engine developed 30 horse-power, and weighed only about 7 lbs.
per horse-power developed, its design and workmanship being far
ahead of any previous design in this respect, with the exception
of the remarkable engine, designed by Manly, installed in
Langley's ill-fated aeroplane--or 'aerodrome,' as he preferred to
call it--tried in 1903.

The light weight of the Wright brothers' engine did not
necessitate a high number of revolutions per minute to get the
requisite power; the speed was only 1,300 revolutions per
minute, which, with a piston stroke of 3.94 inches, was quite
moderate.  Four cylinders were used, the cylinder diameter being
4.42 inches; the engine was of the vertical type, arranged to
drive two propellers at a rate of about 350 revolutions per
minute, gearing being accomplished by means of chain drive from
crank-shaft end to propeller spindle.

The methods adopted by the Wrights for obtaining a light-weight
engine were of considerable interest, in view of the fact that
the honour of first achieving flight by means of the driven plane
belongs to them--unless Ader actually flew as he claimed.  The
cylinders of this first Wright engine were separate castings of
steel, and only the barrels were jacketed, this being done by
fixing loose, thin aluminium covers round the outside of each
cylinder.  The combustion head and valve pockets were cast
together with the cylinder barrel, and were not water cooled. 
The inlet valves were of the automatic type, arranged on the tops
of the cylinders, while the exhaust valves were also overhead,
operated by rockers and push-rods.  The pistons and piston rings
were of the ordinary type, made of cast-iron, and the connecting
rods were circular in form, with a hole drilled down the middle
of each to reduce the weight.

Necessity for increasing power and ever lighter weight in
relation to the power produced has led to the evolution of a
number of different designs of internal combustion engines.  It
was quickly realised that increasing the number of cylinders on
an engine was a better way of getting more power than that of
increasing the cylinder diameter, as the greater number of
cylinders gives better torque-even turning effect--as well as
keeping down the weight--this latter because the bigger
cylinders must be more stoutly constructed than the small sizes;
this fact has led to the construction of engines having as many
as eighteen cylinders, arranged in three parallel rows in order
to keep the length of crankshaft within reasonable limits.  The
aero engine of to-day may, roughly, be divided into four
classes:  these are the V type, in which two rows of cylinders
are set parallel at a certain angle to each other; the radial
type, which consists of cylinders arranged radially and
remaining stationary while the crankshaft revolves; the rotary,
where the cylinders are disposed round a common centre and
revolve round a stationary shaft, and the vertical type, of four
or six cylinders--seldom more than this--arranged in one row.  A
modification of the V type is the eighteen-cylindered engine--
the Sunbeam is one of the best examples--in which three rows of
cylinders are set parallel to each other, working on a common
crankshaft.  The development these four types started with that
of the vertical--the simplest of all; the V, radial, and rotary
types came after the vertical, in the order given.

The evolution of the motor-car led to the adoption of the
vertical type of internal combustion engine in preference to any
other, and it followed naturally that vertical engines should be
first used for aeroplane propulsion, as by taking an engine that
had been developed to some extent, and adapting it to its new
work, the problem of mechanical flight was rendered easier than
if a totally new type had had to be evolved.  It was quickly
realised--by the Wrights, in fact-that the minimum of weight per
horse-power was the prime requirement for the successful
development of heavier-than-air machines, and at the same time
it was equally apparent that the utmost reliability had to be
obtained from the engine, while a third requisite was economy,
in order to reduce the weight of petrol necessary for flight.

Daimler, working steadily toward the improvement of the internal
combustion engine, had made considerable progress by the end of
last century.  His two-cylinder engine of 1897 was approaching
to the present-day type, except as regards the method of
ignition; the cylinders had 3.55 inch diameter, with a 4.75 inch
piston stroke, and the engine was rated at 4.5 brake horse-power,
though it probably developed more than this in actual running at
its rated speed of 800 revolutions per minute.  Power was limited
by the inlet and exhaust passages, which, compared with
present-day practice, were very small.  The heavy castings of
which the engine was made up are accounted for by the necessity
for considering foundry practice of the time, for in 1897
castings were far below the present-day standard.  The crank-case
of this two-cylinder vertical Daimler engine was the only part
made of aluminium, and even with this no attempt was made to
attain lightness, for a circular flange was cast at the bottom to
form a stand for the engine during machining and erection.  The
general design can be followed from the sectional views, and
these will show, too, that ignition was by means of a hot tube on
the cylinder head, which had to be heated with a blow-lamp before
starting the engine.  With all its well known and hated troubles,
at that time tube ignition had an advantage over the magneto, and
the coil and accumulator system, in reliability; sparking plugs,
too, were not so reliable then as they are now.  Daimler fitted a
very simple type of carburettor to this engine, consisting only
of a float with a single jet placed in the air passage.  It may
be said that this twin-cylindered vertical was the first of the 
series from which has been evolved the Mercedes-Daimler car and
airship engines, built in sizes up to and even beyond 240
horse-power.

In 1901 the development of the petrol engine was still so slight
that it did not admit of the construction, by any European
maker, of an engine weighing less than 12 lbs. per horse-power. 
Manly, working at the instance of Professor Langley, produced a
five-cylindered radial type engine, in which both the design and
workmanship showed a remarkable advance in construction.  At 950
revolutions per minute it developed 52.4 horse-power, weighing
only 2.4 pounds per horse-power; it was a very remarkable
achievement in engine design, considering the power developed in
relation to the total weight, and it was, too, an interruption
in the development of the vertical type which showed that there
were other equally great possibilities in design.

In England, the first vertical aero-engine of note was that
designed by Green, the cylinder dimensions being 4.15 inch
diameter by 4.75 stroke--a fairly complete idea of this engine
can be obtained from the accompanying diagrams. At a speed of
1,160 revolutions per minute it developed 35 brake horse-power,
and by accelerating up to 1,220 revolutions per minute a maximum
of 40 brake horse-power could be obtained--the first-mentioned
was the rated working speed of the engine for continuous runs. 
A flywheel, weighing 23.5 lbs., was fitted to the engine, and
this, together with the ignition system, brought the weight up
to 188 lbs., giving 5.4 lbs. per horse-power.  In comparison with
the engine fitted to the Wrights' aeroplane a greater power was
obtained from approximately the same cylinder volume, and an
appreciable saving in weight had also been effected.  The
illustration shows the arrangement of the vertical valves at the
top of the cylinder and the overhead cam shaft, while the
position of the carburettor and inlet pipes can be also seen. 
The water jackets were formed by thin copper casings, each
cylinder being separate and having its independent jacket rigidly
fastened to the cylinder at the top only, thus allowing for free
expansion of the casing; the joint at the bottom end was formed
by sliding the jacket over a rubber ring.  Each cylinder was
bolted to the crank-case and set out of line with the crankshaft,
so that the crank has passed over the upper dead centre by the
time that the piston is at the top of its stroke when receiving
the full force of fuel explosion.  The advantage of this
desaxe setting is that the pressure in the cylinder acts on the
crank-pin with a more effective leverage during that part of the
stroke when that pressure is highest, and in addition the side
pressure of the piston on the cylinder wall, due to the thrust of
the connecting rod, is reduced.  Possibly the charging of the
cylinder is also more complete by this arrangement, owing to the
slower movement of the piston at the bottom of its stroke
allowing time for an increased charge of mixture to enter the
cylinder.

A 60 horse-power engine was also made, having four vertical
cylinders, each with a diameter of 5.5 inches and stroke of 5.75
inches, developing its rated power at 1,100 revolutions per
minute.  By accelerating up to 1,200 revolutions per minute 70
brake horsepower could be obtained, and a maximum of 80 brake
horse-power was actually attained with the type.  The flywheel,
fitted as with the original 35 horse-power engine, weighed 37
lbs.; with this and with the ignition system the total weight of
the engine was only 250 lbs., or 4.2 lbs. per horse-power at
the normal rating.  In this design, however, low weight in
relation to power was not the ruling factor, for Green gave more
attention to reliability and economy of fuel consumption, which
latter was approximately 0.6 pint of petrol per brake
horse-power per hour.  Both the oil for lubricating the bearings
and the water for cooling the cylinders were circulated by
pumps, and all parts of the valve gear, etc., were completely
enclosed for protection from dust.

A later development of the Green engine was a six-cylindered
vertical, cylinder dimensions being 5.5 inch diameter by 6 inch
stroke, developing 120 brake horsepower when running at 1,250
revolutions per minute. The total weight of the engine with
ignition system 398 was 440 lbs., or 3.66 lbs. per horse-power. 
One of these engines was used on the machine which, in 1909, won
the prize of L1,000 for the first circular mile flight, and it
may be noted, too, that S. F. Cody, making the circuit of England
in 1911, used a four-cylinder Green engine.  Again, it was a
Green engine that in 1914 won the L5,000 prize offered for the
best aero engine in the Naval and Military aeroplane engine
competition.

Manufacture of the Green engines, in the period of the War, had
standardised to the production of three types. Two of these were
six-cylinder models, giving respectively 100 and 150 brake
horse-power, and the third was a twelve-cylindered model rated
at 275 brake horse-power.

In 1910 J. S. Critchley compiled a list showing the types of
engine then being manufactured; twenty-two out of a total of
seventy-six were of the four-cylindered vertical type, and in
addition to these there were two six-cylindered verticals. 
The sizes of the four-cylinder types ranged from 26 up to 118
brake horse-power; fourteen of them developed less than 50
horse-power, and only two developed over 100 horse-power.

It became apparent, even in the early stages of heavier-than-air
flying, that four-cylinder engines did not produce the even
torque that was required for the rotation of the power shaft,
even though a flywheel was fitted to the engine.  With this type
of engine the breakage of air-screws was of frequent occurrence,
and an engine having a more regular rotation was sought, both
for this and to avoid the excessive vibration often experienced
with the four-cylinder type.  Another, point that forced itself
on engine builders was that the increased power which was
becoming necessary for the propulsion of aircraft made an
increase in the number of cylinders essential, in order to obtain
a light engine.  An instance of the weight reduction obtainable
in using six cylinders instead of four is shown in Critchley's
list, for one of the four-cylinder engines developed 118.5 brake
horse-power and weighed 1,100 lbs., whereas a six-cylinder engine
by the same manufacturer developed 117.5 brake horse-power with a
weight of 880 lbs., the respective cylinder dimensions being
7.48 diameter by 9.06 stroke for the four-cylinder engine, and
6.1 diameter by 7.28 stroke for the six-cylinder type.

A list of aeroplane engines, prepared in 1912 by Graham Clark,
showed that, out of the total number of 112 engines then
being manufactured, forty-two were of the vertical type, and of
this number twenty-four had four-cylinders while sixteen were
six-cylindered.  The German aeroplane engine trials were held a
year later, and sixty-six engines entered the competition,
fourteen of these being made with air-cooled cylinders.  All of
the ten engines that were chosen for the final trials were of
the water-cooled type, and the first place was won by a Benz
four-cylinder vertical engine which developed 102 brake
horse-power at 1,288 revolutions per minute.  The cylinder
dimensions of this engine were 5.1 inch diameter by 7.1 inch
stroke, and the weight of the engine worked out at 3.4 lbs. per
brake horse-power.  During the trials the full-load petrol
consumption was 0.53 pint per horse-power per hour, and the
amount of lubricating oil used was 0.0385 pint per brake
horse-power per hour.  In general construction this Benz engine
was somewhat similar to the Green engine already described; the
overhead valves, fitted in the tops of the cylinders, were
similarly arranged, as was the cam-shaft; two springs were
fitted to each of the valves to guard against the possibility of
the engine being put out of action by breakage of one of the
springs, and ignition was obtained by two high-tension magnetos
giving simultaneous sparks in each cylinder by means of two
sparking plugs--this dual ignition reduced the possibility of
ignition troubles.  The cylinder jackets were made of welded
sheet steel so fitted around the cylinder that the head was also
water-cooled, and the jackets were corrugated in the middle to
admit of independent expansion.  Even the lubrication system was
duplicated, two sets of pumps being used, one to circulate the
main supply of lubricating oil, and the other to give a
continuous supply of fresh oil to the bearings, so that if the
supply from one pump failed the other could still maintain
effective lubrication.

Development of the early Daimler type brought about the
four-cylinder vertical Mercedes-Daimler engine of 85 horse-power,
with cylinders of 5.5 diameter with 5.9 inch stroke, the
cylinders being cast in two pairs.  The overhead arrangement of
valves was adopted, and in later designs push-rods were
eliminated, the overhead cam-shaft being adopted in their place. 
By 1914 the four-cylinder Mercedes-Daimler had been partially
displaced from favour by a six-cylindered model, made in two
sizes; the first of these gave a nominal brake horse-power of 80,
having cylinders of 4.1 inches diameter by 5.5 inches stroke; the
second type developed 100 horse-power with cylinders 4.7 inches
in diameter and 5.5 inches stroke, both types being run at 1,200
revolutions per minute.  The cylinders of both these types were
cast in pairs, and, instead of the water jackets forming part of
the casting, as in the design of the original four-cylinder
Mercedes-Daimler engine, they were made of steel welded to
flanges on the cylinders.  Steel pistons, fitted with cast-iron
rings, were used, and the overhead arrangement of valves and
cam-shaft was adopted.  About 0.55 pint per brake horse-power per
hour was the usual fuel consumption necessary to full load
running, and the engine was also economical as regards the
consumption of lubricating oil, the lubricating system being
'forced' for all parts, including the cam-shaft.  The shape of
these engines was very well suited for work with aircraft, being
narrow enough to admit of a streamline form being obtained, while
all the accessories could be so mounted as to produce little or
no wind resistance, and very little obstruction to the pilot's
view.

The eight-cylinder Mercedes-Daimler engine, used for airship
propulsion during the War, developed 240 brake horse-power at
1,100 revolutions per minute; the cylinder dimensions were 6.88
diameter by 6.5 stroke--one of the instances in which the short
stroke in relation to bore was very noticeable.

Other instances of successful vertical design-the types already
detailed are fully sufficient to give particulars of the type
generally--are the Panhard, Chenu, Maybach, N.A.G., Argus,
Mulag, and the well-known Austro-Daimler, which by 1917 was
being copied in every combatant country.  There are also the
later Wright engines, and in America the Wisconsin six-cylinder
vertical, weighing well under 4 lbs. per horse-power, is
evidence of the progress made with this first type of aero
engine to develop.



II. THE VEE TYPE

An offshoot from the vertical type, doubling the power of this
with only a very slight--if any--increase in the length of
crankshaft, the Vee or diagonal type of aero engine leaped to
success through the insistent demand for greater power. 
Although the design came after that of the vertical engine, by
1910, according to Critchley's list of aero engines, there
were more Vee type engines being made than any other type,
twenty-five sizes being given in the list, with an average
rating of 57.4 brake horse-power.

The arrangement of the cylinders in Vee form over the
crankshaft, enabling the pistons of each pair of opposite
cylinders to act upon the same crank pin, permits of a very
short, compact engine being built, and also permits of reduction
of the weight per horsepower, comparing this with that of the
vertical type of engine, with one row of cylinders.  Further, at
the introduction of this type of engine it was seen that
crankshaft vibration, an evil of the early vertical engines, was
practically eliminated, as was the want of longitudinal
stiffness that characterised the higher-powered vertical
engines.

Of the Vee type engines shown in Critchley's list in 1910
nineteen different sizes were constructed with eight cylinders,
and with horse-powers ranging from thirty to just over the
hundred; the lightest of these weighed 2.9 lbs. per
horse-power--a considerable advance in design on the average
vertical engine, in this respect of weight per horse-power. 
There were also two sixteen-cylinder engines of Vee design, the
larger of which developed 134 horse-power with a weight of only 2
lbs. per brake horse-power.  Subsequent developments have
indicated that this type, with the further development from it of
the double-Vee, or engine with three rows of cylinders, is likely
to become the standard design of aero engine where high powers
are required.  The construction permits of placing every part so
that it is easy of access, and the form of the engine implies
very little head resistance, while it can be placed on the
machine--supposing that machine to be of the single-engine
type--in such a way that the view of the pilot is very little
obstructed while in flight.

An even torque, or great uniformity of rotation, is transmitted
to the air-screw by these engines, while the design also permits
of such good balance of the engine itself that vibration is
practically eliminated.  The angle between the two rows of
cylinders is varied according to the number of cylinders, in
order to give working impulses at equal angles of rotation and
thus provide even torque; this angle is determined by dividing
the number of degrees in a circle by the number of cylinders in
either row of the engine.  In an eight-cylindered Vee type
engine, the angle between the cylinders is 90 degrees; if it is
a twelve-cylindered engine, the angle drops to 60 degrees.

One of the earliest of the British-built Vee type engines was an
eight-cylinder 50 horse-power by the Wolseley Company,
constructed in 1908 with a cylinder bore of 3.75 inches and
stroke of 5 inches, running at a normal speed of 1,350
revolutions per minute.  With this engine, a gearing was
introduced to enable the propeller to run at a lower speed than
that of the engine, the slight loss of efficiency caused by the
friction of the gearing being compensated by the slower speed of
the air-screw, which had higher efficiency than would have been
the case if it had been run at the engine speed.  The ratio of
the gearing--that is, the speed of the air-screw relatively to
that of the engine, could be chosen so as to suit exactly the
requirements of the air-screw, and the gearing itself, on this
engine, was accomplished on the half-speed shaft actuating the
valves.

Very soon after this first design had been tried out, a second
Vee type engine was produced which, at 1,200 revolutions per
minute, developed 60 horse-power; the size of this engine was
practically identical with that of its forerunner, the only
exception being an increase of half an inch in the cylinder
stroke--a very long stroke of piston in relation to the bore of
the cylinder.  In the first of these two engines, which was
designed for airship propulsion, the weight had been about 8
lbs. per brake horse-power, no special attempt appearing to
have been made to fine down for extreme lightness; in this 60
horse-power design, the weight was reduced to 6.1 lbs. per
horse-power, counting the latter as normally rated; the
engine actually gave a maximum of 75 brake horse-power, reducing
the ratio of weight to power very considerably below the figure
given.

The accompanying diagram illustrates a later Wolseley model, end
elevation, the eight-cylindered 120 horse-power Vee type aero
engine of the early war period.  With this engine, each crank
pin has two connecting rods bearing on it, these being placed
side by side and connected to the pistons of opposite cylinders
and the two cylinders of the pair are staggered by an amount
equal to the width of the connecting rod bearing, to afford 
accommodation for the rods.  The crankshaft was a nickel chrome
steel forging, machined hollow, with four crank pins set at 180
degrees to each other, and carried in three bearings lined with
anti-friction metal.  The connecting rods were made of tubular
nickel chrome steel, and the pistons of drawn steel, each being
fitted with four piston rings.  Of these the two rings nearest to
the piston head were of the ordinary cast-iron type, while the
others were of phosphor bronze, so arranged as to take the side
thrust of the piston.  The cylinders were of steel, arranged in
two groups or rows of four, the angular distance between them
being 90 degrees.  In the space above the crankshaft, between the
cylinder rows, was placed the valve-operating mechanism, together
with the carburettor and ignition system, thus rendering this a
very compact and accessible engine.  The combustion heads of the
cylinders were made of cast-iron, screwed into the steel cylinder
barrels; the water-jacket was of spun aluminium, with one end
fitting over the combustion head and the other free to slide on
the cylinder; the water-joint at the lower end was made tight by
a Dermatine ring carried between small flanges formed on the
cylinder barrel.  Overhead valves were adopted, and in order to
make these as large as possible the combustion chamber was made
slightly larger in diameter than the cylinder, and the valves set
at an angle.  Dual ignition was fitted in each cylinder, coil and
accumulator being used for starting and as a reserve in case of
failure of the high-tension magneto system fitted for normal
running.  There was a double set of lubricating pumps, ensuring
continuity of the oil supply to all the bearings of the engine.

The feature most noteworthy in connection with the running of
this type of engine was its flexibility; the normal output of
power was obtained with 1,150 revolutions per minute of the
crankshaft, but, by accelerating up to 1,400 revolutions, a
maximum of 147 brake horse-power could be obtained.  The weight
was about 5 lbs. per horse-power, the cylinder dimensions being
5 inches bore by 7 inches stroke.  Economy in running was
obtained, the fuel consumption being 0.58 pint per brake
horse-power per hour at full load, with an expenditure of about
0.075 pint of lubricating oil per brake horse-power per hour.

Another Wolseley Vee type that was standardised was a 90
horse-power eight-cylinder engine running at 1,800 revolutions
per minute, with a reducing gear introduced by fitting the air
screw on the half-speed shaft.  First made semi-cooled--the
exhaust valve was left air-cooled, and then entirely
water-jacketed--this engine demonstrated the advantage of full
water cooling, for under the latter condition the same power was
developed with cylinders a quarter of an inch less in diameter
than in the semi-cooled pattern; at the same time the weight was
brought down to 4 1/2 lbs. per horsepower.

A different but equally efficient type of Vee design was the
Dorman engine, of which an end elevation is shown; this
developed 80 brake horse-power at a speed of 1,300 revolutions
per minute, with a cylinder bore of 5 inches; each cylinder was
made in cast-iron in one piece with the combustion chamber, the
barrel only being water-jacketed.  Auxiliary exhaust ports were
adopted, the holes through the cylinder wall being uncovered by
the piston at the bottom of its stroke--the piston, 4.75 inches
in length, was longer than its stroke, so that these ports were
covered when it was at the top of the cylinder.  The exhaust
discharged through the ports into a belt surrounding the
cylinder, the belts on the cylinders being connected so that the
exhaust gases were taken through a single pipe.  The air was
drawn through the crank case, before reaching the carburettor,
this having the effect of cooling the oil in the crank case as
well as warming the air and thus assisting in vaporising the
petrol for each charge of the cylinders.  The inlet and exhaust
valves were of the overhead type, as may be gathered from the
diagram, and in spite of cast-iron cylinders being employed a
light design was obtained, the total weight with radiator,
piping, and water being only 5.5 lbs. per horse-power.

Here was the antithesis of the Wolseley type in the matter of
bore in relation to stroke; from about 1907 up to the beginning
of the war, and even later, there was controversy as to which
type--that in which the bore exceeded the stroke, or vice
versa--gave greater efficiency.  The short-stroke enthusiasts
pointed to the high piston speed of the long-stroke type, while
those who favoured the latter design contended that full power
could not be obtained from each explosion in the short-stroke
type of cylinder.  It is now generally conceded that the
long-stroke engine yields higher efficiency, and in addition to
this, so far as car engines are concerned, the method of rating
horse-power in relation to bore without taking stroke into
account has given the long-stroke engine an advantage, actual
horse-power with a long stroke engine being in excess of the
nominal rating.  This may have had some influence on aero engine
design, but, however this may have been, the long-stroke engine
has gradually come to favour, and its rival has taken second
place.

For some time pride of place among British Vee type engines was
held by the Sunbeam Company, which, owing to the genius of Louis
Coatalen, together with the very high standard of construction
maintained by the firm, achieved records and fame in the middle
and later periods of the war.  Their 225 horse-power
twelve-cylinder engine ran at a normal speed of 2,000 revolutions
per minute; the air screw was driven through gearing at half this
speed, its shaft being separate from the timing gear and carried
in ball-bearings on the nose-piece of the engine.  The cylinders
were of cast-iron, entirely water-cooled; a thin casing formed
the water-jacket, and a very light design was obtained, the
weight being only 3.2 lbs. per horse-power.  The first engine of
Sunbeam design had eight cylinders and developed 150 horse-power
at 2,000 revolutions per minute; the final type of Vee design
produced during the war was twelve-cylindered, and yielded 310
horse-power with cylinders 4.3 inches bore by 6.4 inches stroke. 
Evidence in favour of the long-stroke engine is afforded in this
type as regards economy of working; under full load, working at
2,000 revolutions per minute, the consumption was 0.55 pints of
fuel per brake horse-power per hour, which seems to indicate that
the long stroke permitted of full use being made of the power
resulting from each explosion, in spite of the high rate of speed
of the piston.

Developing from the Vee type, the eighteen-cylinder 475 brake
horse-power engine, designed during the war, represented
for a time the limit of power obtainable from a single plant. 
It was water-cooled throughout, and the ignition to each
cylinder was duplicated; this engine proved fully efficient, and
economical in fuel consumption.  It was largely used for
seaplane work, where reliability was fully as necessary as high
power.

The abnormal needs of the war period brought many British firms
into the ranks of Vee-type engine-builders, and, apart from
those mentioned, the most notable types produced are the
Rolls-Royce and the Napier.  The first mentioned of these firms,
previous to 1914 had concentrated entirely on car engines, and
their very high standard of production in this department of
internal combustion engine work led, once they took up the
making of aero engines, to extreme efficiency both of design and
workmanship.  The first experimental aero engine, of what became
known as the 'Eagle' type, was of Vee design--it was completed
in March of 1915--and was so successful that it was standardised
for quantity production.  How far the original was from the
perfection subsequently ascertained is shown by the steady
increase in developed horse-power of the type; originally
designed to develop 200 horse-power, it was developed and
improved before its first practical trial in October of 1915,
when it developed 255 horsepower on a brake test.  Research and
experiment produced still further improvements, for, without any
enlargement of the dimensions, or radical alteration in design,
the power of the engine was brought up to 266 horse-power by
March of 1916, the rate of revolutions of 1,800 per minute being
maintained throughout.  July, 1916 gave 284 horse-power; by the
cud of the year this had been increased to 322 horse-power; by
September of 1917 the increase was to 350 horse-power, and by
February of 1918 then 'Eagle' type of engine was rated at 360
horse-power, at which standard it stayed.  But there is no more
remarkable development in engine design than this, a 75 per cent
increase of power in the same engine in a period of less than
three years.

To meet the demand for a smaller type of engine for use on
training machines, the Rolls-Royce firm produced the 'Hawk'
Vee-type engine of 100 horsepower, and, intermediately between
this and the 'Eagle,' the 'Falcon' engine came to being with an
original rated horse-power of 205 at 1,800 revolutions per
minute, in April of 1916.  Here was another case of growth of
power in the same engine through research, almost similar to
that of the 'Eagle' type, for by July of 1918 the 'Falcon' was
developing 285 horse-power with no radical alteration of
design.  Finally, in response to the constant demand for
increase of power in a single plant, the Rolls-Royce company
designed and produced the 'Condor' type of engine, which yielded
600 horse-power on its first test in August of 1918.  The
cessation of hostilities and consequent falling off in the
demand for extremely high-powered plants prevented the 'Condor'
being developed to its limit, as had been the 'Falcon' and
'Eagle' types.

The 'Eagle 'engine was fitted to the two Handley-Page
aeroplanes--which made  flights from England to India--it was
virtually standard on the  Handley-Page bombers of the later War
period, though  to a certain extent the American 'Liberty' engine
was  also used.  Its chief record, however, is that of being the
type fitted to the Vickers-Vimy aeroplane which made the first
Atlantic flight, covering the distance of 1,880 miles at a speed
averaging 117 miles an hour.

The Napier Company specialised on one type of engine from the
outset, a power plant which became known as the 'Lion' engine,
giving 450 horse-power with twelve cylinders arranged in three
rows of four each.  Considering the engine as 'dry,' or without
fuel and accessories, an abnormally light weight per
horse-power--only 1.89 lbs.--was attained when running at the
normal rate of revolution.  The cylinders and water-jackets are
of steel, and there is fitted a detachable aluminium cylinder
head containing inlet and exhaust valves and valve actuating
mechanism; pistons are of aluminium alloy, and there are two
inlet and two exhaust valves to each cylinder, the whole of the
valve mechanism being enclosed in an oil-tight aluminium case.
Connecting rods and crankshaft are of steel, the latter being
machined from a solid steel forging and carried in five roller
bearings and one plain bearing at the forward end.  The front end
of the crank-case encloses reduction gear for the propeller
shaft, together with the shaft and bearings.  There are two
suction and one pressure type oil pumps driven through gears at
half-engine speed, and two 12 spark magnetos, giving 2 sparks in
each cylinder.

The cylinders are set with the central row vertical, and the two
side rows at angles of 60 degrees each; cylinder bore is 5 1/2
inches, and stroke 5 1/8 inches; the normal rate of revolution
is 1,350 per minute, and the reducing gear gives one revolution
of the propeller shaft to 1.52 revolutions of crankshaft.  Fuel
consumption is 0.48lbs. of fuel per brake horse-power hour at
full load, and oil consumption is 0.020 lbs. per brake horsepower
hour.  The dry weight of the engine, complete with propeller
boss, carburettors, and induction pipes, is 850 lbs., and the
gross weight in running order, with fuel and oil for six hours
working, is 2,671 lbs., exclusive of cooling water.

To this engine belongs an altitude record of 30,500 feet, made at
Martlesham, near Ipswich, on January 2nd, 1919, by Captain Lang,
R.A.F., the climb being accomplished in 66 minutes 15 seconds. 
Previous to this, the altitude record was held by an Italian
pilot, who made 25,800 feet in an hour and 57 minutes in 1916. 
Lang's climb was stopped through the pressure of air, at the
altitude he reached, being insufficient for driving the small
propellers on the machine which worked the petrol and oil pumps,
or he might have made the height said to have been attained by
Major Schroeder on February 27th, 1920, at Dayton, Ohio. 
Schroeder is said to have reached an altitude of 36,020 feet on a
Napier biplane, and, owing to failure of the oxygen supply, to
have lost consciousness, fallen five miles, righted his machine
when 2,000 feet in the air, and alighted successfully.  Major
Schroeder is an American.

Turning back a little, and considering other than British design
of Vee and double-Vee or 'Broad arrow' type of engine, the
Renault firm from the earliest days devoted considerable
attention to the development of this type, their air-cooled
engines having been notable examples from the earliest days of
heavier-than-air machines.  In 1910 they were making three sizes
of eight-cylindered Vee-type engines, and by 1915 they had
increased to the manufacture of five sizes, ranging from 25 to
100 brake horse-power, the largest of the five sizes having
twelve cylinders but still retaining the air-cooled principle. 
The De Dion firm, also, made Vee-type engines in 1914, being
represented by an 80 horse-power eight-cylindered engine,
air-cooled, and a 150 horse-power, also of eight cylinders,
water-cooled, running at a normal rate of 1,600 revolutions per
minute.  Another notable example of French construction was the
Panhard and Levassor 100 horse-power eight-cylinder Vee engine,
developing its rated power at 1,500 revolutions per minute, and
having the--for that time--low weight of 4.4 lbs. per
horse-power.

American Vee design has followed the British fairly cclosely;
the Curtiss Company produced originally a 75 horse-power
eight-cylinder Vee type running at 1,200 revolutions per minute,
supplementing this with a 170 horse-power engine running at
1,600 revolutions per minute, and later with a twelve-cylinder
model Vee type, developing 300 horse-power at 1,500 revolutions
per minute, with cylinder bore of 5 inches and stroke of 7
inches.  An exceptional type of American design was the Kemp Vee
engine of 80 horse-power in which the cylinders were cooled by a
current of air obtained from a fan at the forward end of the
engine.  With cylinders of 4.25 inches bore and 4.75 inches
stroke, the rater power was developed at 1,150 revolutions per
minute, and with the engine complete the weight was only 4.75
lbs. per horse-power.



III. THE RADIAL  TYPE

The very first successful design of internal combustion aero
engine made was that of Charles Manly, who built a five-cylinder
radial engine in 1901 for use with Langley's 'aerodrome,' as the
latter inventor decided to call what has since become known as
the aeroplane.  Manly made a number of experiments, and finally
decided on radial design, in which the cylinders are so rayed
round a central crank-pin that the pistons act successively upon
it; by this arrangement a very short and compact engine is
obtained, with a minimum of weight, and a regular crankshaft
rotation and perfect balance of inertia forces.

When Manly designed his radial engine, high speed internal
combustion engines were in their infancy, and the difficulties in
construction can be partly realised when the lack of
manufacturing methods for this high-class engine work, and the
lack of experimental data on the various materials, are taken
into account.  During its tests, Manly's engine developed 52.4
brake horsepower at a speed of 950 revolutions per minute, with
the remarkably low weight of only 2.4 lbs. per horsepower; this
latter was increased to 3.6 lbs. when the engine was completed by
the addition of ignition system, radiator, petrol tank, and all
accessories, together with the cooling water for the cylinders.

In Manly's engine, the cylinders were of steel, machined  outside
and inside to 1/16 of an inch thickness; on the side of cylinder,
at the top end, the valve chamber was brazed, being machined
from a solid forging,  The casing which formed the water-jacket
was of sheet steel, 1/50 of an inch in thickness, and this also
was brazed on the cylinder and to the valve chamber.  Automatic
inlet valves were fitted, and  the exhaust valves were operated
by a cam which had two points, 180 degrees apart; the cam was
rotated in the opposite direction to the engine at one-quarter
engine speed.  Ignition was obtained by using a one-spark coil
and vibrator for all cylinders, with a distributor to select the
right cylinder for each spark--this was before the days of the
high-tension magneto and the almost perfect ignition systems that
makers now employ.  The scheme of ignition for this engine was
originated by Manly himself, and he also designed the sparking
plugs fitted in the tops of the cylinders.  Through fear of
trouble resulting if the steel pistons worked on the steel
cylinders, cast iron liners were introduced in the latter,  1/16
of an inch thick.

The connecting rods of this engine were of virtually the same
type as is employed on nearly all modern radial engines.  The
rod for one cylinder had a bearing along the whole of the crank
pin, and its end enclosed the pin; the other four rods had
bearings upon the end of the first rod, and did not touch the
crank pin.  The accompanying diagram shows this construction,
together with the means employed for securing the ends of the
four rods--the collars were placed in position after the rods
had been put on.  The bearings of these rods did not receive any
of the rubbing effect due to the rotation of the crank pin, the
rubbing on them being only that of the small angular displacement
of the rods during each revolution; thus there was no difficulty
experienced with the lubrication.

Another early example of the radial type of engine was the
French Anzani, of which type one was fitted to the machine with
which Bleriot first crossed the English  Channel--this was of 25
horse-power.  The earliest  Anzani engines were of the
three-cylinder fan type, one cylinder being vertical, and the
other two placed at an angle of 72 degrees on each side, as the
possibility of over-lubrication of the bottom cylinders was
feared if a regular radial construction were adopted.  In order
to overcome the unequal balance of this type, balance weights
were fitted inside the crank case.

The final development of this three-cylinder radial was the 'Y'
type of engine, in which the cylinders were regularly disposed
at 120 degrees apart, the bore was 4.1, stroke 4.7 inches, and
the power developed was 30 brake horse-power at 1,300
revolutions per minute.

Critchley's list of aero engines being constructed in 1910 shows
twelve of the radial type, with powers of between 14 and 100 
horse-power, and with from three to ten cylinder--this last is
probably the greatest number of cylinders that can be
successfully arranged in circular form.  Of the twelve types of
1910, only two were water-cooled, and it is to be noted that
these two ran at the slowest speeds and had the lowest weight per
horse-power of any.

The Anzani radial was considerably developed special attention
being paid to this type by its makers and by 1914 the Anzani
list comprised seven different sizes of air-cooled radials.  Of
these the largest had twenty cylinders, developing 200 brake
horse-power--it was virtually a double radial--and the smallest
was the original 30 horse-power three-cylinder design.  A
six-cylinder model was formed by a combination of two groups of
three cylinders each, acting upon a double-throw crankshaft; the
two crank pins were set at 180 degrees to each other, and the
cylinder groups were staggered by an amount equal to the
distance between the centres of the crank pins.  Ten-cylinder
radial engines are made with two groups of five cylinders acting
upon two crank pins set at 180 degrees to each other, the largest
Anzani 'ten' developed 125 horsepower at 1,200 revolutions per
minute, the ten cylinders being each 4.5 inches in bore with
stroke of 5.9 inches, and the weight of the engine being 3.7 lbs.
per horse-power.  In the 200 horse-power Anzani radial the
cylinders are arranged in four groups of five each, acting on two
crank pins.  The bore of the cylinders in this engine is the same
as in the three-cylinder, but the stroke is increased to 5.5
inches.  The rated power is developed at 1,300 revolutions per
minute, and the engine complete weighs 3.4 lbs. per horse-power.

With this 200 horse-power Anzani, a petrol consumption of as low
as 0.49 lbs. of fuel per brake horse-power per hour has been
obtained, but the consumption of lubricating oil is
compensatingly high, being up to one-fifth of the fuel used.  The
cylinders are set desaxe with the crank shaft, and are of
cast-iron, provided with radiating ribs for air-cooling; they are
attached to the crank case by long bolts passing through bosses
at the top of the cylinders, and connected to other bolts at
right angles through the crank case.  The tops of the cylinders
are formed flat, and seats for the inlet and exhaust valves are
formed on them.  The pistons are cast-iron, fitted with ordinary
cast-iron spring rings.  An aluminium crank case is used, being
made in two halves connected together by bolts, which latter also
attach the engine to the frame of the machine.  The crankshaft
is of nickel steel, made hollow, and mounted on ball-bearings in
such a manner that practically a combination of ball and plain
bearings is obtained; the central web of the shaft is bent to
bring the centres of the crank pins as close together as
possible, leaving only room for the connecting rods, and the pins
are 180 degrees apart.  Nickel steel valves of the cone-seated,
poppet type are fitted, the inlet valves being automatic, and
those for the exhaust cam-operated by means of push-rods.  With
an engine having such a number of cylinders a very uniform
rotation of the crankshaft is obtained, and in actual running
there are always five of the cylinders giving impulses to the
crankshaft at the same time.

An interesting type of pioneer radial engine was the Farcot, in
which the cylinders were arranged in a horizontal plane, with a
vertical crankshaft which operated the air-screw through bevel
gearing.  This was an eight-cylinder engine, developing 64
horse-power at 1,200 revolutions per minute.  The R.E.P. type,in
the early days, was a 'fan' engine, but the designer, M. Robert
Pelterie, turned from this design to a seven-cylinder radial,
which at 1,100 revolutions per minute gave 95 horse-power.
Several makers entered into radial engine development in the
years immediately preceding the War, and in 1914 there were some
twenty-two different sizes and types, ranging from 30 to 600
horse-power, being made, according to report; the actual
construction of the latter size at this time, however, is
doubtful.

Probably the best example of radial construction up to the
outbreak of War was the Salmson (Canton-Unne) water-cooled, of
which in 1914 six sizes were listed as available.  Of these
the smallest was a seven-cylinder 90 horse-power engine, and the
largest, rated at 600 horse-power, had eighteen cylinders. 
These engines, during the War, were made under license by the
Dudbridge Ironworks in Great Britain.

The accompanying diagram shows the construction of the cylinders
in the 200 horse-power size, showing the method of cooling, and
the arrangement of the connecting rods.  A patent planetary gear,
also shown in the diagram, gives exactly the same stroke to all
the pistons.  The complete engine has fourteen cylinders, of
forged steel machined all over, and so secured to the crank
case that any one can be removed without parting the crank case. 
The water-jackets are of spun copper, brazed on to the cylinder,
and corrugated so as to admit of free expansion; the water is
circulated by means of a centrifugal pump.  The pistons are of
cast-iron, each fitted with three rings, and the connecting rods
are of high grade steel, machined all over and fitted with
bushes of phosphor bronze; these rods are connected to a central
collar, carried on the crank pin by two ball-bearings.  The
crankshaft has a single throw, and is made in two parts to allow
the cage for carrying the big end-pins of the connecting rods to
be placed in position.

The casing is in two parts, on one of which the brackets for
fixing the engine are carried, while the other part carries the
valve-gear.  Bolts secure the two parts together.  The
mechanically-operated steel valves on the cylinders are each
fitted with double springs and the valves are operated by rods
and levers.  Two Zenith carburettors are fitted on the rear half
of the crank case, and short induction pipes are led to each
cylinder; each of the carburettors is heated by the exhaust
gases.  Ignition is by two high-tension magnetos, and a
compressed air self-starting arrangement is provided.  Two oil
pumps are fitted for lubricating purposes, one of which forces
oil to the crankshaft and connecting-rod bearings, while the
second forces oil to the valve gear, the cylinders being so
arranged that the oil which flows along the walls cannot flood
the lower cylinders.  This engine operates upon a six-stroke
cycle, a rather rare arrangement for internal combustion engines
of the electrical ignition type; this is done in order to obtain
equal angular intervals for the working impulses imparted to the
rotating crankshaft, as the cylinders are arranged in groups of
seven, and all act upon the one crankshaft.  The angle,
therefore, between the impulses is 77 1/7 degrees.  A diagram is
inset giving a side view of the engine, in order to show the
grouping of the cylinders.

The 600 horse-power Salmson engine was designed with a view to
fitting to airships, and was in reality two nine-cylindered
engines, with a gear-box connecting them; double air-screws were
fitted, and these were so arranged that either or both of them
might be driven by either or both engines; in addition to this,
the two engines were complete and separate engines as regards
carburation and ignition, etc., so that they could be run
independently of each other.  The cylinders were exceptionally
'long stroke,' being 5.9 inches bore to 8.27 inches stroke, and
the rated power was developed at 1,200 revolutions per minute,
the weight of the complete engine being only 4.1 lbs. per
horse-power at the normal rating.

A type of engine specially devised for airship propulsion is
that in which the cylinders are arranged horizontally instead of
vertically, the main advantages of this form being the reduction
of head resistance and less obstruction to the view of the
pilot.  A casing, mounted on the top of the engine, supports the
air-screw, which is driven through bevel gearing from the upper
end of the crankshaft.  With this type of engine a better rate
of air-screw efficiency is obtained by gearing the screw down to
half the rate of revolution of the engine, this giving a more
even torque.  The petrol consumption of the type is very low,
being only 0.48 lbs. per horse-power per hour, and equal
economy is claimed as regards lubricating oil, a consumption of
as little as 0.04 lbs. per horse-power per hour being claimed.

Certain American radial engines were made previous to 1914, the
principal being the Albatross six-cylinder engines of 50 and 100
horse-powers.  Of these the smaller size was air-cooled, with
cylinders of 4.5 inches bore and 5 inches stroke, developing the
rated power at 1,230 revolutions per minute, with a weight of
about 5 lbs. per horse-power.  The 100 horse-power size had
cylinders of 5.5 inches bore, developing its rated power at 1,230
revolutions per minute, and weighing only 2.75 lbs. per
horse-power.  This engine was markedly similar to the
six-cylindered Anzani, having all the valves mechanically
operated, and with auxiliary exhaust ports at the bottoms of the
cylinders, overrun by long pistons.  These Albatross engines had
their cylinders arranged in two groups of three, with each group
of three pistons operating on one of two crank pins, each
180 degrees apart.

The radial type of engine, thanks to Charles Manly, had the
honour of being first in the field as regards aero work.  Its
many advantages, among which may be specially noted the very
short crankshaft as compared with vertical, Vee, or 'broad arrow'
type of engine, and consequent greater rigidity, ensure it
consideration by designers of to-day, and render it certain that
the type will endure.  Enthusiasts claim that the 'broad arrow'
type, or Vee with a third row of cylinders inset between the
original two, is just as much a development from the radial
engine as from the vertical and resulting Vee; however this may
be, there is a place for the radial type in air-work for as long
as the internal combustion engine remains as a power plant.



IV. THE ROTARY TYPE

M. Laurent Seguin, the inventor of the Gnome rotary aero engine,
provided as great a stimulus to aviation as any that was given
anterior to the war period, and brought about a great advance in
mechanical flight, since these well-made engines gave a
high-power output for their weight, and were extremely smooth
in running.  In the rotary design the crankshaft of the engine
is stationary, and the cylinders, crank case, and all their
adherent parts rotate; the working is thus exactly opposite in
principle to that of the radial type of aero engine, and the
advantage of the rotary lies in the considerable flywheel effect
produced by the revolving cylinders, with consequent evenness of
torque.  Another advantage is that air-cooling, adopted in all
the Gnome engines, is rendered much more effective by the
rotation of the cylinders, though there is a tendency to
distortion through the leading side of each cylinder being more
efficiently cooled than the opposite side; advocates of other
types are prone to claim that the air resistance to the
revolving cylinders absorbs some 10 per cent of the power
developed by the rotary engine, but that has not prevented the
rotary from attaining to great popularity as a prime mover.

There were, in the list of aero engines compiled in 1910,
five rotary engines included, all air-cooled.  Three of these
were Gnome engines, and two of the make known as 'International.'
They ranged from 21.5 to 123 horse-power, the latter being rated
at only 1.8 lbs. weight per brake horse-power, and having
fourteen cylinders, 4.33 inches in diameter by 4.7 inches stroke. 
By 1914 forty-three different sizes and types of rotary engine
were being constructed, and in 1913 five rotary type engines were
entered for the series of aeroplane engine trials held in
Germany.  Minor defects ruled out four of these, and only the
German Bayerischer Motoren Flugzeugwerke completed the seven-hour
test prescribed for competing engines.  Its large fuel
consumption barred this engine from the final trials, the
consumption being some 0.95 pints per horse-power per hour.  The
consumption of lubricating oil, also was excessive, standing at
0.123 pint per horse-power per hour.  The engine gave 37.5
effective horse-power during its trial, and the loss due to air
resistance was 4.6 horse-power, about 11 per cent.  The
accompanying drawing shows the construction of the engine, in
which the seven cylinders are arranged radially on the crank
case; the method of connecting the pistons to the crank pins can
be seen.  The mixture is drawn through the crank chamber, and to
enter the cylinder it passes through the two automatic valves in
the crown of the piston; the exhaust valves are situated in the
tops of the cylinders, and are actuated by cams and push-rods.
Cooling of the cylinder is assisted by the radial rings, and the
diameter of these rings is increased round the hottest part of
the cylinder.  When long flights are undertaken the advantage of
the light weight of this engine is more than counterbalanced by
its high fuel and lubricating oil consumption, but there are
other makes which are much better than this seven-cylinder German
in respect of this.

Rotation of the cylinders in engines of this type is produced by
the side pressure of the pistons on the cylinder walls, and in
order to prevent this pressure from becoming abnormally large it
is necessary to keep the weight of the piston as low as possible,
as the pressure is produced by the tangential acceleration and
retardation of the piston.  On the upward stroke the
circumferential velocity of the piston is rapidly increased,
which causes it to exert a considerable tangential pressure on
the side of the cylinder, and on the return stroke there is a
corresponding retarding effect due to the reduction of the
circumferential velocity of the piston.  These side pressures
cause an appreciable increase in the temperatures of the
cylinders and pistons, which makes it necessary to keep the
power rating of the engines fairly low.

Seguin designed his first Gnome rotary as a 34 horse-power
engine when run at a speed of 1,300 revolutions per minute.  It
had five cylinders, and the weight was 3.9 lbs. per horse-power. 
A seven-cylinder model soon displaced this first engine, and
this latter, with a total weight of 165 lbs., gave 61.5
horse-power.  The cylinders were machined out of solid nickel
chrome-steel ingots, and the machining was carried out so that
the cylinder walls were under 1/6 of an inch in thickness.  The
pistons were cast-iron, fitted each with two rings, and the
automatic inlet valve to the cylinder was placed in the crown of
the piston.  The connecting rods, of 'H' section, were of nickel
chrome-steel, and the large end of one rod, known as the
'master-rod' embraced the crank pin; on the end of this rod six
hollow steel pins were carried, and to these the remaining six
connecting-rods were attached.  The crankshaft of the engine was
made of nickel chrome-steel, and was in two parts connected
together at the crank pin; these two parts, after the master-rod
had been placed in position and the other connecting rods had
been attached to it, were firmly secured.  The steel crank case
was made in five parts, the two central ones holding the
cylinders in place, and on one side another of the five castings
formed a cam-box, to the outside of which was secured the
extension to which the air-screw was attached.  On the other
side of the crank case another casting carried the thrust-box,
and the whole crank case, with its cylinders and gear, was
carried on the fixed crank shaft by means of four ball-bearings,
one of which also took the axial thrust of the air-screw.

For these engines, castor oil is the lubricant usually adopted,
and it is pumped to the crankshaft by means of a gear-driven oil
pump; from this shaft the other parts of the engine are
lubricated by means of centrifugal force, and in actual practice
sufficient unburnt oil passes through the cylinders to lubricate
the exhaust valve, which partly accounts for the high rate of
consumption of lubricating oil.  A very simple carburettor of
the float less, single-spray type was used, and the mixture was
passed along the hollow crankshaft to the interior of the crank
case, thence through the automatic inlet valves in the tops of
the pistons to the combustion chambers of the cylinders. 
Ignition was by means of a high-tension magneto specially geared
to give the correct timing, and the working impulses occurred at
equal angular intervals of 102.85 degrees.  The ignition was
timed so that the firing spark occurred when the cylinder was 26
degrees before the position in which the piston was at the outer
end of its stroke, and this timing gave a maximum pressure in
the cylinder just after the piston had passed this position.

By 1913, eight different sizes of the Gnome engine were being
constructed, ranging from 45 to 180 brake horse-power; four of
these were single-crank engines one having nine and the other
three having seven cylinders. The remaining four were
constructed with two cranks; three of them had fourteen
cylinders apiece, ranged in groups of seven, acting on the
cranks, and the one other had eighteen cylinders ranged in two
groups of nine, acting on its two cranks.  Cylinders of the
two-crank engines are so arranged (in the fourteen-cylinder
type) that fourteen equal angular impulses occur during each
cycle; these engines are supported on bearings on both sides of
the engine, the air-screw being placed outside the front
support.  In the eighteen-cylinder model the impulses occur at
each 40 degrees of angular rotation of the cylinders, securing
an extremely even rotation of the air-screw.

In 1913 the Gnome Monosoupape engine was introduced, a model in
which the inlet valve to the cylinder was omitted, while the
piston was of the ordinary cast-iron type.  A single exhaust
valve in the cylinder head was operated in a manner similar to
that on the previous Gnome engines, and the fact of this being
the only valve on the cylinder gave the engine its name.  Each
cylinder contained ports at the bottom which communicated with
the crank chamber, and were overrun by the piston when this
was approaching the bottom end of its stroke.  During the
working cycle of the engine the exhaust valve was opened early
to allow the exhaust gases to escape from the cylinder, so that
by the time the piston overran the ports at the bottom the
pressure within the cylinder was approximately equal to that in
the crank case, and practically no flow of gas took place in
either direction through the ports.  The exhaust valve remained
open as usual during the succeeding up-stroke of the piston, and
the valve was held open until the piston had returned through
about one-third of its downward stroke, thus permitting fresh air
to enter the cylinder.  The exhaust valve then closed, and the
downward motion of the piston, continuing, caused a partial
vacuum inside the cylinder; when the piston overran the ports,
the rich mixture from the crank case immediately entered.  The
cylinder was then full of the mixture, and the next upward stroke
of the piston compressed the charge; upon ignition the working
cycle was repeated.  The speed variation of this engine was
obtained by varying the extent and duration of the opening of the
exhaust valves, and was controlled by the pilot by hand-operated
levers acting on the valve tappet rollers.  The weight per
horsepower of these engines was slightly less than that of the
two-valve type, while the lubrication of the gudgeon pin and
piston showed an improvement, so that a lower lubricating oil
consumption was obtained.  The 100 horse-power Gnome Monosoupape
was built with nine cylinders, each 4.33 inches bore by 5.9
inches stroke, and it developed its rated power at 1,200
revolutions per minute.

An engine of the rotary type, almost as well known as the Gnome,
is the Clerget, in which both cylinders and crank case are made
of steel, the former having the usual radial fins for cooling. 
In this type the inlet and exhaust valves are both located in
the cylinder head, and mechanically operated by push-rods and
rockers.  Pipes are carried from the crank case to the inlet
valve casings to convey the mixture to the cylinders, a
carburettor of the central needle type being used.  The
carburetted mixture is taken into the crank case chamber in a
manner similar to that of the Gnome engine.  Pistons of
aluminium alloy, with three cast-iron rings, are fitted, the top
ring being of the obturator type.  The large end of one of the
nine connecting rods embraces the crank pin and the pressure is
taken on two ball-bearings housed in the end of the rod. This
carries eight pins, to which the other rods are attached, and the
main rod being rigid between the crank pin and piston pin
determines the position of the pistons.  Hollow connecting-rods
are used, and the lubricating oil for the piston pins passes from
the crankshaft through the centres of the rods.  Inlet and
exhaust valves can be set quite independently of one another--a
useful point, since the correct timing of the opening of these
valves is of importance.  The inlet valve opens 4 degrees from
top centre and closes after the bottom dead centre of the piston;
the exhaust valve opens 68 degrees before the bottom centre and
closes 4 degrees after the top dead centre of the piston.  The
magnetos are set to give the spark in the cylinder at 25 degrees
before the end of the compression stroke--two high-tension
magnetos are used:  if desired, the second one can be adjusted to
give a later spark for assisting the starting of the engine.  The
lubricating oil pump is of the valveless two-plunger type, so
geared that it runs at seven revolutions to 100 revolutions of
the engine; by counting the pulsations the speed of the engine
can be quickly calculated by multiplying the pulsations by 100
and dividing by seven.  In the 115 horse-power nine-cylinder
Clerget the cylinders are 4.7 bore with a 6.3 inches stroke, and
the rated power of the engine is obtained at 1,200 revolutions
per minute.  The petrol consumption is 0.75 pint per horse-power
per hour.

A third rotary aero engine, equally well known with the
foregoing two, is the Le Rhone, made in four different sizes
with power outputs of from 50 to 160 horse-power; the two
smaller sizes are single crank engines with seven and nine
cylinders respectively, and the larger sizes are of double-crank
design, being merely the two smaller sizes doubled--fourteen and
eighteen-cylinder engines.  The inlet and exhaust valves are
located in the cylinder head, and both valves are mechanically
operated by one push-rod and rocker, radial pipes from crank
case to inlet valve casing taking the mixture to the cylinders. 
The exhaust valves are placed on the leading, or air-screw side,
of the engine, in order to get the fullest possible cooling
effect.  The rated power of each type of engine is obtained at
1,200 revolutions per minute, and for all four sizes the
cylinder bore is 4.13 inches, with a 5.5 inches piston stroke. 
Thin cast-iron liners are shrunk into the steel cylinders in
order to reduce the amount of piston friction.  Although the Le
Rhone engines are constructed practically throughout of steel,
the weight is only 2.9 lbs. per horse-power in the
eighteen-cylinder type.

American enterprise in the construction of the rotary type is
perhaps best illustrated in the 'Gyro 'engine; this was first
constructed with inlet valves in the heads of the pistons, after
the Gnome pattern, the exhaust valves being in the heads of the
cylinders.  The inlet valve in the crown of each piston was
mechanically operated in a very ingenious manner by the
oscillation of the connecting-rod. The Gyro-Duplex engine
superseded this original design, and a small cross-section
illustration of this is appended.  It is constructed in seven and
nine-cylinder sizes, with a power range of from 50 to 100
horse-power; with the largest size the low weight of 2.5 lbs.. 
per horse-power is reached.  The design is of considerable
interest to the internal combustion engineer, for it embodies a
piston valve for controlling auxiliary exhaust ports, which also
acts as the inlet valve to the cylinder.  The piston uncovers the
auxiliary ports when it reaches the bottom of its stroke, and at
the end of the power stroke the piston is in such a position that
the exhaust can escape over the top of it.  The exhaust valve in
the cylinder head is then opened by means of the push-rod and
rocker, and is held open until the piston has completed its
upward stroke and returned through more than half its subsequent
return stroke.  When the exhaust valve closes, the cylinder has a
charge of fresh air, drawn in through the exhaust valve, and the
further motion of the piston causes a partial vacuum; by the time
the piston reaches bottom dead centre the piston-valve has moved
up to give communication between the cylinder and the crank case,
therefore the mixture is drawn into the cylinder.  Both the
piston valve and exhaust valve are operated by cams formed on the
one casting, which rotates at seven-eighths engine speed for the
seven-cylinder type, and nine-tenths engine speed for the
nine-cylinder engines.  Each of these cams has four or five
points respectively, to suit the number of cylinders.

The steel cylinders are machined from solid forgings and
provided with webs for air-cooling as shown.  Cast-iron pistons
are used, and are connected to the crankshaft in the same manner
as with the Gnome and Le Rhone engines.  Petrol is sprayed into
the crank case by a small geared pump and the mixture is taken
from there to the piston valves by radial pipes.  Two separate
pumps are used for lubrication, one forcing oil to the crank-pin
bearing and the other spraying the cylinders.

Among other designs of rotary aero engines the E.J.C. is
noteworthy, in that the cylinders and crank case of this engine
rotate in opposite directions, and two air-screws are used, one
being attached to the end of the crankshaft, and the other to the
crank case.  Another interesting type is the Burlat rotary, in
which both the cylinders and crankshaft rotate in the same
direction, the rotation of the crankshaft being twice that of the
cylinders as regards speed.  This engine is arranged to work on
the four-stroke cycle with the crankshaft making four, and the
cylinders two, revolutions per cycle.

It would appear that the rotary type of engine is capable of but
little more improvement--save for such devices as these of the
last two engines mentioned, there is little that Laurent Seguin
has not already done in the Gnome type.  The limitation of the
rotary lies in its high fuel and lubricating oil consumption,
which renders it unsuited for long-distance aero work; it was,
in the war period, an admirable engine for such short runs as
might be involved in patrol work 'over the lines,' and for
similar purposes, but the watercooled Vee or even vertical, with
its much lower fuel consumption, was and is to be preferred for
distance work.  The rotary air-cooled type has its uses, and for
them it will probably remain among the range of current types
for some time to come.  Experience of matters aeronautical is
sufficient to show, however, that prophecy in any direction is
most unsafe.



V. THE HORIZONTALLY-OPPOSED ENGINE

Among the first internal combustion engines to be taken into use
with aircraft were those of the horizontally-opposed four-stroke
cycle type, and, in every case in which these engines were used,
their excellent balance and extremely even torque rendered them
ideal-until the tremendous increase in power requirements
rendered the type too long and bulky for placing in the fuselage
of an aeroplane.  As power increased, there came a tendency
toward placing cylinders radially round a central crankshaft,
and, as in the case of the early Anzani, it may be said that the
radial engine grew out of the horizontal opposed piston type. 
There were, in 1910--that is, in the early days of small power
units, ten different sizes of the horizontally opposed engine
listed for manufacture, but increase in power requirements
practically ruled out the type for air work.

The Darracq firm were the leading makers of these engines in
1910; their smallest size was a 24 horsepower engine, with two
cylinders each of 5.1 inches bore by 4.7 inches stroke.  This
engine developed its rated power at 1,500 revolutions per
minute, and worked out at a weight of 5 lbs. per horse-power. 
With these engines the cranks are so placed that two regular
impulses are given to the crankshaft for each cycle of working,
an arrangement which permits of very even balancing of the
inertia forces of the engine.  The Darracq firm also made a
four-cylindered horizontal opposed piston engine, in which two
revolutions were given to the crankshaft per revolution, at
equal angular intervals.

The Dutheil-Chambers was another engine of this type, and had
the distinction of being the second largest constructed.  At
1,000 revolutions per minute it developed 97 horse-power; its
four cylinders were each of 4.93 inches bore by 11.8 inches
stroke--an abnormally long stroke in comparison with the bore. 
The weight--which owing to the build of the engine and its length
of stroke was bound to be rather high, actually amounted to 8.2
lbs. per horse-power.  Water cooling was adopted, and the engine
was, like the Darracq four-cylinder type, so arranged as to give
two impulses per revolution at equal angular intervals of
crankshaft rotation.

One of the first engines of this type to be constructed in
England was the Alvaston, a water-cooled model which was made in
20, 30, and 50 brake horse-power sizes, the largest being a
four-cylinder engine.  All three sizes were constructed to run
at 1,200 revolutions per minute.  In this make the cylinders
were secured to the crank case by means of four long tie bolts
passing through bridge pieces arranged across the cylinder
heads, thus relieving the cylinder walls of all longitudinal
explosion stresses.  These bridge pieces were formed from chrome
vanadium steel and milled to an 'H' section, and the bearings
for the valve-tappet were forged solid with them.  Special
attention was given to the machining of the interiors of the
cylinders and the combustion heads, with the result that the
exceptionally high compression of 95 lbs. per square inch was
obtained, giving a very flexible engine.  The cylinder heads
were completely water-jacketed, and copper water-jackets were
also fitted round the cylinders.  The mechanically operated
valves were actuated by specially shaped cams, and were so
arranged that only two cams were required for the set of eight
valves.  The inlet valves at both ends of the engine were
connected by a single feed-pipe to which the carburettor was
attached, the induction piping being arranged above the engine
in an easily accessible position.  Auxiliary air ports were
provided in the cylinder walls so that the pistons overran them
at the end of their stroke.  A single vertical shaft running in
ball-bearings operated the valves and water circulating pump,
being driven by spiral gearing from the crankshaft at half
speed.  In addition to the excellent balance obtained with this
engine, the makers claimed with justice that the number of
working parts was reduced to an absolute minimum.

In the two-cylinder Darracq, the steel cylinders were machined
from solid, and auxiliary exhaust ports, overrun by the piston
at the inner end of its stroke, were provided in the cylinder
walls, consisting of a circular row of drilled holes--this
arrangement was subsequently adopted on some of the Darracq
racing car engines.  The water jackets were of copper, soldered
to the cylinder walls; both the inlet and exhaust valves were
located in the cylinder heads, being operated by rockers and
push-rods actuated by cams on the halftime shaft driven from one
end of the crankshaft.  Ignition was by means of a high-tension
magneto, and long induction pipes connected the-ends of the
cylinders to the carburettor, the latter being placed underneath
the engine.  Lubrication was effected by spraying oil into the
crank case by means of a pump, and a second pump circulated the
cooling water.

Another good example of this type of engine was the Eole, which
had eight opposed pistons, each pair of which was actuated by a
common combustion chamber at the centre of the engine, two
crankshafts being placed at the outer ends of the engine.  This
reversal of the ordinary arrangement had two advantages; it
simplified induction, and further obviated the need for cylinder
heads, since the explosion drove at two piston heads instead of
at one piston head and the top of the cylinder; against this,
however, the engine had to be constructed strongly enough to
withstand the longitudinal stresses due to the explosions, as
the cranks are placed on the outer ends and the cylinders and
crank-cases take the full force of each explosion.  Each
crankshaft drove a separate air-screw.

This pattern of engine was taken up by the Dutheil-Chambers firm
in the pioneer days of aircraft, when the firm in question
produced seven different sizes of horizontal engines.  The
Demoiselle monoplane used by Santos-Dumont in 1909 was fitted
with a two-cylinder, horizontally-opposed Dutheil-Chambers
engine, which developed 25 brake horse-power at a speed of
1,100 revolutions per minute, the cylinders being of 5 inches
bore by 5.1 inches stroke, and the total weight of the engine
being some 120 lbs.  The crankshafts of these engines were
usually fitted with steel flywheels in order to give a very even
torque, the wheels being specially constructed with wire spokes. 
In all the Dutheil-Chambers engines water cooling was adopted,
and the cylinders were attached to the crank cases by means of
long bolts passing through the combustion heads.

For their earliest machines, the Clement-Bayard firm constructed
horizontal engines of the opposed piston type.  The best known of
these was the 30 horse-power size, which had cylinders of 4.7
inches diameter by 5.1 inches stroke, and gave its rated power
at 1,200 revolutions per minute.  In this engine the steel
cylinders were secured to the crank case by flanges, and
radiating ribs were formed around the barrel to assist the
air-cooling.  Inlet and exhaust valves were actuated by
push-rods and rockers actuated from the second motion shaft
mounted above the crank case; this shaft also drove the
high-tension magneto with which the engine was fitted.  A ring
of holes drilled round each cylinder constituted auxiliary ports
which the piston uncovered at the inner end of its stroke, and
these were of considerable assistance not only in expelling
exhaust gases, but also in moderating the temperature of the
cylinder and of the main exhaust valve fitted in the cylinder
head.  A water-cooled Clement-Bayard horizontal engine was also
made, and in this the auxiliary exhaust ports were not embodied;
except in this particular, the engine was very similar to the
water-cooled Darracq.

The American Ashmusen horizontal engine, developing 100
horse-power, is probably the largest example of this type
constructed.  It was made with six cylinders arranged on each
side of a common crank case, with long bolts passing through the
cylinder heads to assist in holding them down.  The induction
piping and valve-operating gear were arranged below the engine,
and the half-speed shaft carried the air-screw.

Messrs Palons and Beuse, Germans, constructed a light-weight,
air-cooled, horizontally-opposed engine, two-cylindered.  In
this the cast-iron cylinders were made very thin, and were
secured to the crank case by bolts passing through lugs cast on
the outer ends of the cylinders; the crankshaft was made hollow,
and holes were drilled through the webs of the connecting-rods
in order to reduce the weight.  The valves were fitted to the
cylinder heads, the inlet valves being of the automatic type,
while the exhaust valves were mechanically operated from the
cam-shaft by means of rockers and push-rods.  Two carburettors
were fitted, to reduce the induction piping to a minimum; one
was attached to each combustion chamber, and ignition was by the
normal high-tension magneto driven from the halftime shaft.

There was also a Nieuport two-cylinder air-cooled horizontal
engine, developing 35 horse-power when running at 1,300
revolutions per minute, and being built at a weight of 5.1 lbs. 
per horse-power.  The cylinders were of 5.3 inches diameter by
5.9 inches stroke; the engine followed the lines of the Darracq
and Dutheil-Chambers pretty closely, and thus calls for no
special description.

The French Kolb-Danvin engine of the horizontal type, first
constructed in 1905, was probably the first two-stroke cycle
engine designed to be applied to the propulsion of aircraft; it
never got beyond the experimental stage, although its trials
gave very good results.  Stepped pistons were adopted, and the
charging pump at one end was used to scavenge the power cylinder
at the other ends of the engine, the transfer ports being formed
in the main casting.  The openings of these ports were
controlled at both ends by the pistons, and the location of the
ports appears to have made it necessary to take the exhaust from
the bottom of one cylinder and from the top of the other.  The
carburetted mixture was drawn into the scavenging cylinders, and
the usual deflectors were cast on the piston heads to assist in
the scavenging and to prevent the fresh gas from passing out of
the exhaust ports.



VI. THE TWO-STROKE CYCLE ENGINE

Although it has been little used for aircraft propulsion, the
possibilities of the two-stroke cycle engine render some study
of it desirable in this brief review of the various types of
internal combustion engine applicable both to aeroplanes and
airships.  Theoretically the two-stroke cycle engine--or as it
is more commonly termed, the 'two-stroke,' is the ideal power
producer; the doubling of impulses per revolution of the
crankshaft should render it of very much more even torque than
the four-stroke cycle types, while, theoretically, there should
be a considerable saving of fuel, owing to the doubling of the
number of power strokes per total of piston strokes.  In
practice, however, the inefficient scavenging of virtually every
two-stroke cycle engine produced nullifies or more than
nullifies its advantages over the four-stroke cycle engine; in
many types, too, there is a waste of fuel gases through the
exhaust ports, and much has yet to be done in the way of
experiment and resulting design before the two-stroke cycle
engine can be regarded as equally reliable, economical, and
powerful with its elder brother.

The first commercially successful engine operating on the
two-stroke cycle was invented by Mr Dugald Clerk, who in 1881
proved the design feasible.  As is more or less generally
understood, the exhaust gases of this engine are discharged from
the cylinder during the time that the piston is passing the
inner dead centre, and the compression, combustion, and
expansion of the charge take place in similar manner to that of
the four-stroke cycle engine.  The exhaust period is usually
controlled by the piston overrunning ports in the cylinder at
the end of its working stroke, these ports communicating direct
with the outer air--the complication of an exhaust valve is thus
obviated; immediately after the escape of the exhaust gases,
charging of the cylinder occurs, and the fresh gas may be
introduced either through a valve in the cylinder head or
through ports situated diametrically opposite to the exhaust
ports.  The continuation of the outward stroke of the piston,
after the exhaust ports have been closed, compresses the charge
into the combustion chamber of the cylinder, and the ignition of
the mixture produces a recurrence of the working stroke.

Thus, theoretically, is obtained the maximum of energy with the
minimum of expenditure; in practice, however, the scavenging of
the power cylinder, a matter of great importance in all internal
combustion engines, is often imperfect, owing to the opening of
the exhaust ports being of relatively short duration; clearing
the exhaust gases out of the cylinder is not fully accomplished,
and these gases mix with the fresh charge and detract from its
efficiency.  Similarly, owing to the shorter space of time
allowed, the charging of the cylinder with the fresh mixture is
not so efficient as in the four-stroke cycle type; the fresh
charge is usually compressed slightly in a separate
chamber--crank case, independent cylinder, or charging pump, and
is delivered to the working cylinder during the beginning of the
return stroke of the piston, while in engines working on the
four-stroke cycle principle a complete stroke is devoted to the
expulsion of the waste gases of the exhaust, and another full
stroke to recharging the cylinder with fresh explosive mixture.

Theoretically the two-stroke and the four-stroke cycle engines
possess exactly the same thermal efficiency, but actually this
is modified by a series of practical conditions which to some
extent tend to neutralise the very strong case in favour of the
two-stroke cycle engine. The specific capacity of the engine
operating on the two-stroke principle is theoretically twice
that of one operating on the four-stroke cycle, and
consequently, for equal power, the former should require only
about half the cylinder volume of the latter; and, owing to the
greater superficial area of the smaller cylinder, relatively,
the latter should be far more easily cooled than the larger
four-stroke cycle cylinder; thus it should be possible to get
higher compression pressures, which in turn should result in
great economy of working.  Also the obtaining of a working
impulse in the cylinder for each revolution of the crankshaft
should give a great advantage in regularity of rotation--which
it undoubtedly does--and the elimination of the operating gear
for the valves, inlet and exhaust, should give greater
simplicity of design.

In spite of all these theoretical--and some practical--advantages
the four-stroke cycle engine was universally adopted for aircraft
work; owing to the practical equality of the two principles of
operation, so far as thermal efficiency and friction losses are
concerned, there is no doubt that the simplicity of design (in
theory) and high power output to weight ratio (also in theory)
ought to have given the 'two-stroke' a place on the aeroplane. 
But this engine has to be developed so as to overcome its
inherent drawbacks; better scavenging methods have yet to be
devised--for this is the principal drawback--before the
two-stroke can come to its own as a prime mover for aircraft.

Mr Dugald Clerk's original two-stroke cycle engine is indicated
roughly, as regards principle, by the accompanying diagram, from
which it will be seen that the elimination of the ordinary inlet
and exhaust valves of the four-stroke type is more than
compensated by a separate cylinder which, having a piston worked
from the connecting-rod of the power cylinder, was used to
charging, drawing the mixture from the carburettor past the
valve in the top of the charging cylinder, and then forcing it
through the connecting pipe into the power cylinder.  The inlet
valves both on the charging and the power cylinders are
automatic; when the power piston is near the bottom of its
stroke the piston in the charging cylinder is compressing the
carburetted air, so that as soon as the pressure within the
power cylinder is relieved by the exit of the burnt gases
through the exhaust ports the pressure in the charging cylinder
causes the valve in the head of the power cylinder to open, and
fresh mixture flows into the cylinder, replacing the exhaust
gases.  After the piston has again covered the exhaust ports the
mixture begins to be compressed, thus automatically closing the
inlet valve. Ignition occurs near the end of the compression
stroke, and the working stroke immediately follows, thus giving
an impulse to the crankshaft on every down stroke of the piston. 
If the scavenging of the cylinder were complete, and the cylinder
were to receive a full charge of fresh mixture for every stroke,
the same mean effective pressure as is obtained with four-stroke
cycle engines ought to be realised, and at an equal speed of
rotation this engine should give twice the power obtainable from
a four-stroke cycle engine of equal dimensions.  This result was
not achieved, and, with the improvements in construction brought
about by experiment up to 1912, the output was found to be only
about fifty per cent more than that of a four-stroke cycle engine
of the same size, so that, when the charging cylinder is
included, this engine has a greater weight per horse-power, while
the lowest rate of fuel consumption recorded was 0.68 lb. per
horse-power per hour.

In 1891 Mr Day invented a two-stroke cycle engine which used the
crank case as a scavenging chamber, and a very large number of
these engines have been built for industrial purposes.  The
charge of carburetted air is drawn through a non-return valve
into the crank chamber during the upstroke of the piston, and
compressed to about 4 lbs. pressure per square inch on the
down stroke.  When the piston approaches the bottom end of its
stroke the upper edge first overruns an exhaust port, and almost
immediately after uncovers an inlet port on the opposite side of
the cylinder and in communication with the crank chamber; the
entering charge, being under pressure, assists in expelling the
exhaust gases from the cylinder.  On the next upstroke the
charge is compressed into the combustion space of the cylinder,
a further charge simultaneously entering the crank case to be
compressed after the ignition for the working stroke.  To
prevent the incoming charge escaping through the exhaust ports
of the cylinder a deflector is formed on the top of the piston,
causing the fresh gas to travel in an upward direction, thus
avoiding as far as possible escape of the mixture to the
atmosphere.  From experiments conducted in 1910 by Professor
Watson and Mr Fleming it was found that the proportion of fresh
gases which escaped unburnt through the exhaust ports diminished
with increase of speed; at 600 revolutions per minute about 36
per cent of the fresh charge was lost; at 1,200 revolutions per
minute this was reduced to 20 per cent, and at 1,500 revolutions
it was still farther reduced to 6 per cent.

So much for the early designs.  With regard to engines of this
type specially constructed for use with aircraft, three designs
call for special mention.  Messrs A. Gobe and H. Diard, Parisian
engineers, produced an eight-cylindered two-stroke cycle engine
of rotary design, the cylinders being co-axial.  Each pair of
opposite pistons was secured together by a rigid connecting rod,
connected to a pin on a rotating crankshaft which was mounted
eccentrically to the axis of rotation of the cylinders.  The
crankshaft carried a pinion gearing with an internally toothed
wheel on the transmission shaft which carried the air-screw.  The
combustible mixture, emanating from a common supply pipe, was led
through conduits to the front ends of the cylinders, in which the
charges were compressed before being transferred to the working
spaces through ports in tubular extensions carried by the
pistons.  These extensions had also exhaust ports, registering
with ports in the cylinder which communicated with the outer air,
and the extensions slid over depending cylinder heads attached to
the crank case by long studs.  The pump charge was compressed in
one end of  each cylinder, and the pump spaces each delivered
into their corresponding adjacent combustion spaces.  The charges
entered the pump spaces during the suction period through
passages which communicated with a central stationary supply
passage at one end of the crank case, communication being cut off
when the inlet orifice to the passage passed out of register with
the port in the stationary member.  The exhaust ports at the
outer end of the combustion space opened just before and closed a
little later than the air ports, and the incoming charge assisted
in expelling the exhaust gases in a manner similar to that of the
earlier types of two-stroke cycle engine; The accompanying rough
diagram assists in showing the working of this engine.

Exhibited in the Paris Aero Exhibition of 1912, the Laviator
two-stroke cycle engine, six-cylindered, could be operated either
as a radial or as a rotary engine, all its pistons acting on a
single crank.  Cylinder dimensions of this engine were 3.94
inches bore by 5.12 inches stroke, and a power output of 50
horse-power was obtained when working at a rate of 1,200
revolutions per minute.  Used as a radial engine, it developed
65 horse-power at the same rate of revolution, and, as the total
weight was about 198 lbs., the weight of about 3 lbs. per
horse-power was attained in radial use.  Stepped pistons were
employed, the annular space between the smaller or power piston
and the walls of the larger cylinder being used as a charging
pump for the power cylinder situated 120 degrees in rear of it. 
The charging cylinders were connected by short pipes to ports in
the crank case which communicated with the hollow crankshaft
through which the fresh gas was supplied, and once in each
revolution each port in the case registered with the port in the
hollow shaft.  The mixture which then entered the charging
cylinder was transferred to the corresponding working
cylinder when the piston of that cylinder had reached the end of
its power stroke, and immediately before this the exhaust ports
diametrically opposite the inlet ports were uncovered; scavenging
was thus assisted in the usual way.  The very desirable feature
of being entirely valveless was accomplished with this engine,
which is also noteworthy for exceedingly compact design.

The Lamplough six-cylinder two-stroke cycle rotary, shown at the
Aero Exhibition at Olympia in 1911, had several innovations,
including a charging pump of rotary blower type.  With the six
cylinders, six power impulses at regular intervals were given on
each rotation; otherwise, the cycle of operations was carried
out much as in other two-stroke cycle engines.  The pump
supplied the mixture under slight pressure to an inlet port in
each cylinder, which was opened at the same time as the exhaust
port, the period of opening being controlled by the piston.  The
rotary blower sucked the mixture from the carburettor and
delivered it to a passage communicating with the inlet ports in
the cylinder walls.  A mechanically-operated exhaust valve was
placed in the centre of each cylinder head, and towards the end
of the working stroke this valve opened, allowing part of the
burnt gases to escape to the atmosphere; the remainder was
pushed out by the fresh mixture going in through the ports at
the bottom end of the cylinder.  In practice, one or other of
the cylinders was always taking fresh mixture while working,
therefore the delivery from the pump was continuous and the
mixture had not to be stored under pressure.

The piston of this engine was long enough to keep the ports
covered when it was at the top of the stroke, and a bottom ring
was provided to prevent the mixture from entering the crank
case.  In addition to preventing leakage, this ring no doubt
prevented an excess of oil working up the piston into the
cylinder.  As the cylinder fired with every revolution, the
valve gear was of the simplest construction, a fixed cam lifting
each valve as the cylinder came into position.  The spring of
the exhaust valve was not placed round the stem in the usual
way, but at the end of a short lever, away from the heat of the
exhaust gases. The cylinders were of cast steel, the crank case
of aluminium, and ball-bearings were fitted to the crankshaft,
crank pins, and the rotary blower pump.  Ignition was by means
of a high-tension magneto of the two-spark pattern, and with a
total weight of 300 lbs. the maximum output was 102 brake
horse-power, giving a weight of just under 3 lbs. per
horse-power.

One of the most successful of the two-stroke cycle engines was
that designed by Mr G. F. Mort and constructed by the New
Engine Company.  With four cylinders of 3.69 inches bore by 4.5
inches stroke, and running at 1,250 revolutions per minute, this
engine developed 50 brake horse-power; the total weight of the
engine was 155 lbs., thus giving a weight of 3.1 lbs. per
horse-power.  A scavenging pump of the rotary type was employed,
driven by means of gearing from the engine crankshaft, and in
order to reduce weight to a minimum the vanes were of aluminium. 
This engine was tried on a biplane, and gave very satisfactory
results.

American design yields two apparently successful two-stroke
cycle aero engines.  A rotary called the Fredericson engine was
said to give an output of 70 brake horse-power with five
cylinders 4.5 inches diameter by 4.75 inches stroke, running
at 1,000 revolutions per minute.  Another, the Roberts
two-stroke cycle engine, yielded 100 brake horse-power from six
cylinders of the stepped piston design; two carburettors, each
supplying three cylinders, were fitted to this engine.  Ignition
was by means of the usual high-tension magneto, gear-driven from
the crankshaft, and the engine, which was water-cooled, was of
compact design.   

It may thus be seen that the two-stroke cycle type got as far as
actual experiment in air work, and that with considerable
success.  So far, however, the greater reliability of the
four-stroke cycle has rendered it practically the only aircraft
engine, and the two-stroke has yet some way to travel before it
becomes a formidable competitor, in spite of its admitted
theoretical and questioned practical advantages.



VII. ENGINES OF THE WAR PERIOD

The principal engines of British, French, and American design
used in the war period and since are briefly described under the
four distinct types of aero engine; such notable examples as the
Rolls-Royce, Sunbeam, and Napier engines have been given special
mention, as they embodied--and still embody--all that is best in
aero engine practice.  So far, however, little has been said
about the development of German aero engine design, apart from
the early Daimler and other pioneer makes.

At the outbreak of hostilities in 1914, thanks to subsidies to
contractors and prizes to aircraft pilots, the German aeroplane
industry was in a comparatively flourishing condition.  There
were about twenty-two establishments making different types of
heavier-thanair machines, monoplane and biplane, engined for the
most part with the four-cylinder Argus or the six-cylinder
Mercedes vertical type engines, each of these being of 100
horse-power--it was not till war brought increasing demands on
aircraft that the limit of power began to rise. Contemporary
with the Argus and Mercedes were the Austro-Daimler, Benz, and
N.A.G., in vertical design, while as far as rotary types were
concerned there were two, the Oberursel and the Stahlhertz; of
these the former was by far the most promising, and it came to
virtual monopoly of the rotary-engined plane as soon as the war
demand began.  It was practically a copy of the famous Gnome
rotary, and thus deserves little description.

Germany, from the outbreak of war, practically, concentrated on
the development of the Mercedes engine; and it is noteworthy
that, with one exception, increase of power corresponding with
the increased demand for power was attained without increasing
the number of cylinders.  The various models ranged between 75
and 260 horse-power, the latter being the most recent production
of this type.  The exception to the rule was the eight-cylinder
240 horse-power, which was replaced by the 260 horse-power
six-cylinder model, the latter being more reliable and but very
slightly heavier.  Of the other engines, the 120 horsepower
Argus and the 160 and 225 horse-power Benz were the most used,
the Oberursel being very largely discarded after the Fokker
monoplane had had its day, and the N.A.G. and Austro-Daimler 
Daimler also falling to comparative disuse.  It may be said that
the development of the Mercedes engine contributed very largely
to such success as was achieved in the war period by German
aircraft, and, in developing the engine, the builders were
careful to make alterations in such a way as to effect the least
possible change in the design of aeroplane to which they were to
be fitted.  Thus the engine base of the 175 horse-power model
coincided precisely with that of the 150 horse-power model, and
the 200 and 240 horse-power models retained the same base
dimensions.  It was estimated, in 1918, that well over eighty
per cent of German aircraft was engined with the Mercedes type.

In design and construction, there was nothing abnormal about the
Mercedes engine, the keynote throughout being extreme
reliability and such simplification of design as would permit of
mass production in different factories.  Even before the war,
the long list of records set up by this engine formed practical
application of the wisdom of this policy; Bohn's flight of 24
hours 10 minutes, accomplished on July 10th and 11th, 1914, 
9is an instance of this--the flight was accomplished on an
Albatross biplane with a 75 horsepower Mercedes engine.  The
radial type, instanced in other countries by the Salmson and
Anzani makes, was not developed in Germany; two radial engines
were made in that country before the war, but the Germans seemed
to lose faith in the type under war conditions, or it may have
been that insistence on standardisation ruled out all but the
proved examples of engine.

Details of one of the middle sizes of Mercedes motor, the 176
horse-power type, apply very generally to the whole range; this
size was in use up to and beyond the conclusion of hostilities,
and it may still be regarded as characteristic of modern (1920)
German practice.  The engine is of the fixed vertical type,
has six cylinders in line, not off-set, and is water-cooled. 
The cam shaft is carried in a special bronze casing, seated on
the immediate top of the cylinders, and a vertical shaft is
interposed between crankshaft and camshaft, the latter being
driven by bevel gearing.

On this vertical connecting-shaft the water pump is located,
serving to steady the motion of the shaft.  Extending immediately
below the camshaft is another vertical shaft, driven by bevel
gears from the crank-shaft, and terminating in a worm which
drives the multiple piston oil pumps.

The cylinders are made from steel forgings, as are the valve
chamber elbows, which are machined all over and welded together. 
A jacket of light steel is welded over the valve elbows and
attached to a flange on the cylinders, forming a water-cooling
space with a section of about 7/16 of an inch.  The cylinder
bore is 5.5 inches, and the stroke 6.29 inches.  The cylinders
are attached to the crank case by means of dogs and long through
bolts, which have shoulders near their lower ends and are bolted
to the lower half of the crank chamber.  A very light and rigid
structure is thus obtained, and the method of construction won
the flattery of imitation by makers of other nationality.

The cooling system for the cylinders is extremely efficient. 
After leaving the water pump, the water enters the top of the
front cylinders and passes successively through each of the six
cylinders of the row; short tubes, welded to the tops of the
cylinders, serve as connecting links in the system.  The Panhard
car engines for years were fitted with a similar cooling system,
and the White and Poppe lorry engines were also similarly
fitted; the system gives excellent cooling effect where it is
most needed, round the valve chambers and the cylinder heads.

The pistons are built up from two pieces; a dropped forged steel
piston head, from which depend the piston pin bosses, is
combined with a cast-iron skirt, into which the steel head is
screwed.  Four rings are fitted, three at the upper and one at
the lower end of the piston skirt, and two lubricating oil
grooves are cut in the skirt, in addition to the ring grooves. 
Two small rivets retain the steel head on the piston skirt after
it has been screwed into position, and it is also welded at two
points.  The coefficient of friction between the cast-iron and
steel is considerably less than that which would exist between
two steel parts, and there is less tendency for the skirt to
score the cylinder walls than would be the case if all steel were
used--so noticeable is this that many makers, after giving steel
pistons a trial, discarded them in favour of cast-iron; the Gnome
is an example of this, being originally fitted with a steel
piston carrying a brass ring, discarded in favour of a cast-iron
piston with a percentage of steel in the metal mixture.  In the
Le Rhone engine the difficulty is overcome by a cast-iron liner
to the cylinders.

The piston pin of the Mercedes is of chrome nickel steel, and is
retained in the piston by means of a set screw and cotter pin. 
The connecting rods, of I section, are very short and rigid,
carrying floating bronze bushes which fit the piston pins at the
small end, and carrying an oil tube on each for conveying oil
from the crank pin to the piston pin.

The crankshaft is of chrome nickel steel, carried on seven
bearings.  Holes are drilled through each of the crank pins and
main bearings, for half the diameter of the shaft, and these are
plugged with pressed brass studs.  Small holes, drilled through
the crank cheeks, serve to convey lubricant from the main
bearings to the crank pins.  The propeller thrust is taken by a
simple ball thrust bearing at the propeller end of the
crankshaft, this thrust bearing being seated in a steel retainer
which is clamped between the two halves of the crank case.  At
the forward end of the crankshaft there is mounted a master
bevel gear on six splines; this bevel floats on the splines
against a ball thrust bearing, and, in turn, the thrust is taken
by the crank case cover.  A stuffing box prevents the loss of
lubricant out of the front end of the crank chamber, and an oil
thrower ring serves a similar purpose at the propeller end of the
crank chamber.

With a motor speed of 1,450 r.p.m., the vertical shaft at the
forward end of the motor turns at 2,175 r.p.m., this being the
speed of the two magnetos and the water pump.  The lower
vertical shaft bevel gear and the magneto driving gear are made
integral with the vertical driving shaft, which is carried in
plain bearings in an aluminium housing.  This housing is clamped
to the upper half of the crank case by means of three studs. 
The cam-shaft carries eighteen cams, these being the inlet and
exhaust cams, and a set of half compression cams which are
formed with the exhaust cams and are put into action when
required by means of a lever at the forward end of the
cam-shaft.  The cam-shaft is hollow, and serves as a channel for
the conveyance of lubricating oil to each of the camshaft
bearings.  At the forward end of this shaft there is also
mounted an air pump for maintaining pressure on the fuel supply
tank, and a bevel gear tachometer drive.

Lubrication of the engine is carried out by a full pressure
system.  The oil is pumped through a single manifold, with seven
branches to the crankshaft main bearings, and then in turn
through the hollow crankshaft to the connecting-rod big ends and
thence through small tubes, already noted, to the small end
bearings.  The oil pump has four pistons and two double valves
driven from a single eccentric shaft on which are mounted  four
eccentrics.  The pump is continuously submerged in oil; in order
to avoid great variations in pressure in the oil lines there is
a piston operated pressure regulator, cut in between the pump
and the oil lines.  The two small pistons of the pump take fresh
oil from a tank located in the fuselage of the machine; one of
these delivers oil to the cam shaft, and one delivers to the
crankshaft; this fresh oil mixes with the used oil, returns to
the base, and back to the main large oil pump cylinders.  By
means of these small pump pistons a constant quantity of oil is
kept in the motor, and the oil is continually being freshened by
means of the new oil coming in.  All the oil pipes are very
securely fastened to the lower half of the crank case, and some
cooling of the oil is effected by air passing through channels
cast in the crank case on its way to the carburettor.

A light steel manifold serves to connect the exhaust ports of
the cylinders to the main exhaust pipe, which is inclined about
25 degrees from vertical and is arranged to give on to the
atmosphere just over the top of the upper wing of the aeroplane.

As regards carburation, an automatic air valve surrounds the
throat of the carburettor, maintaining normal composition of
mixture.  A small jet is fitted for starting and running without
load.  The channels cast in the crank chamber, already alluded
to in connection with oil-cooling, serve to warm the air before
it reaches the carburettor, of which the body is water-jacketed.

Ignition of the engine is by means of two Bosch ZH6 magnetos,
driven at a speed of 2,175 revolutions per minute when the engine
is running at its normal speed of 1,450 revolutions.  The maximum
advance of spark is 12 mm., or 32 degrees before the top dead
centre, and the firing order of the cylinders is 1,5,3,6,2,4.

The radiator fitted to this engine, together with the
water-jackets, has a capacity of 25 litres of water, it is
rectangular in shape, and is normally tilted at an angle of 30
degrees from vertical.  Its weight is 26 kg., and it offers but
slight head resistance in flight.

The radial type of engine, neglected altogether in Germany, was
brought to a very high state of perfection at the end of the
War period by British makers.  Two makes, the Cosmos Engineering
Company's 'Jupiter' and 'Lucifer,' and the A.B.C. 'Wasp II' and
'Dragon Fly 1A' require special mention for their light weight
and reliability on trials.

The Cosmos 'Jupiter' was--for it is no longer being made--a 450
horse-power nine-cylinder radial engine, air-cooled, with the
cylinders set in one single row; it was made both geared to
reduce the propeller revolutions relatively to the crankshaft
revolutions, and ungeared; the normal power of the geared type
was 450 horse-power, and the total weight of the engine,
including carburettors, magnetos, etc., was only 757 lbs.; the
engine speed was 1,850 revolutions per minute, and the propeller
revolutions were reduced by the gearing to 1,200.  Fitted to a
'Bristol Badger' aeroplane, the total weight was 2,800 lbs.,
including pilot, passenger, two machine-guns, and full military
load; at 7,000 feet the registered speed, with corrections for
density, was 137 miles per hour; in climbing, the first 2,000
feet was accomplished in 1 minute 4 seconds; 4,000 feet was
reached in 2 minutes 10 seconds; 6,000 feet was reached in 3
minutes 33 seconds, and 7,000  feet in 4 minutes 15 seconds. 
It was intended to modify the plane design and fit a new
propeller, in order to attain even better results, but, if
trials were made with these modifications, the results are not
obtainable.

The Cosmos 'Lucifer' was a three-cylinder radial type engine of
100 horse-power, inverted Y design, made on the simplest possible
principles with a view to quantity production and extreme
reliability.  The rated 100 horse-power was attained at 1,600
revolutions per minute, and the cylinder dimensions were 5.75
bore by 6.25 inches stroke.  The cylinders were of aluminium and
steel mixture, with aluminium heads; overhead valves, operated by
push rods on the front side of the cylinders, were fitted, and a
simple reducing gear ran them at half engine speed.  The crank
case was a circular aluminium casting, the engine being attached
to the fuselage of the aeroplane by a circular flange situated at
the back of the case; propeller shaft and crankshaft were
integral.  Dual ignition was provided, the generator and
distributors being driven off the back end of the engine and the
distributors being easily accessible.  Lubrication was by means
of two pumps, one scavenging and one suction, oil being fed under
pressure from the crankshaft.  A single carburettor fed all three
cylinders, the branch pipe from the carburettor to the circular
ring being provided with an exhaust heater.  The total weight of
the engine, 'all on,' was 280 lbs.

The A.B.C. 'Wasp II,' made by Walton Motors, Limited, is a
seven-cylinder radial, air-cooled engine, the cylinders having a
bore of 4.75 inches and stroke 6.25 inches.  The normal brake
horse-power at 1,650 revolutions is 160, and the maximum 200 at
a speed of 1,850 revolutions per minute.  Lubrication is by
means of two rotary pumps, one feeding through the hollow
crankshaft to the crank pin, giving centrifugal feed to big end
and thence splash oiling, and one feeding to the nose of the
engine, dropping on to the cams and forming a permanent sump for
the gears on the bottom of the engine nose.  Two carburettors
are fitted, and two two-spark magnetos, running at one and
three-quarters engine speed.  The total weight of this engine is
350 lbs., or 1.75 lbs. per horse-power.  Oil consumption at 1,850
revolutions is .03 pints per horse-power per hour, and petrol
consumption is .56 pints per horsepower per hour.  The engine
thus shows as very economical in consumption, as well as very
light in weight.

The A.B.C. 'Dragon Fly 1A 'is a nine-cylinder radial engine
having one overhead inlet and two overhead exhaust valves per
cylinder.  The cylinder dimensions are 5.5 inches bore by 6.5
inches stroke, and the normal rate of speed, 1,650 revolutions
per minute, gives 340 horse-power.  The oiling is by means of
two pumps, the system being practically identical with that of
the 'Wasp II.'  Oil consumption is .021 pints per brake
horse-power per hour, and petrol consumption .56 pints--the
same as that of the 'Wasp II.'  The weight of the complete
engine, including propeller boss, is 600 lbs., or 1,765 lbs.
per horse-power.

These A.B.C. radials have proved highly satisfactory on tests,
and their extreme simplicity of design and reliability commend
them as engineering products and at the same time demonstrate
the value, for aero work, of the air-cooled radial
design--when this latter is accompanied by sound workmanship. 
These and the Cosmos engines represent the minimum of weight per 
horse-power yet attained, together with a practicable degree of
reliability, in radial and probably any aero engine design.



                       APPENDIX A

GENERAL MENSIER'S REPORT ON THE TRIALS OF CLEMENT ADER'S AVION.

                                  Paris, October 21, 1897.

Report on the trials of M. Clement Ader's aviation apparatus.

M. Ader having notified the Minister of War by letter, July 21,
1897, that the Apparatus of Aviation which he had agreed to
build under the conditions set forth in the convention of July
24th, 1894, was ready, and therefore requesting that trials be
undertaken before a Committee appointed for this purpose as per
the decision of August 4th, the Committee was appointed as
follows:--

Division General Mensier, Chairman; Division General Delambre,
Inspector General of the Permanent Works of Coast Defence,
Member of the Technical Committee of the Engineering Corps;
Colonel Laussedat, Director of the Conservatoire des Arts et
Metiers; Sarrau, Member of the Institute, Professor of
Mechanical Engineering at the Polytechnic School; Leaute, Member
of the Institute, Professor of Mechanical Engineering at the
Polytechnique School.

Colonel Laussedat gave notice at once that his health and work
as Director of the Conservatoire des Arts et Metiers did not
permit him to be a member of the Committee; the Minister
therefore accepted his resignation on September 24th, and
decided not to replace him.

Later on, however, on the request of the Chairman of the
Committee, the Minister appointed a new member General Grillon,
commanding the Engineer Corps of the Military Government of
Paris.

To carry on the trials which were to take place at the camp of
Satory, the Minister ordered the Governor of the Military Forces
of Paris to requisition from the Engineer Corps, on the request
of the Chairman of the Committee, the men necessary to prepare
the grounds at Satory.

After an inspection made on the 16th an aerodrome was chosen. 
M. Ader's idea was to have it of circular shape with a width of
40 metres and an average diameter of 450 metres.  The preliminary
work, laying out the grounds, interior and exterior
circumference, etc., was finished at the end of August; the work
of smoothing off the grounds began September 1st with forty-five
men and two rollers, and was finished on the day of the first
tests, October 12th.

The first meeting of the Committee was held August 18th in M.
Ader's workshop; the object being to demonstrate the machine to
the Committee and give all the information possible on the tests
that were to be held. After a careful examination and after
having heard all the explanations by the inventor which were
deemed useful and necessary, the Committee decided that the
apparatus seemed to be built with a perfect understanding of the
purpose to be fulfilled as far as one could judge from a study
of the apparatus at rest; they therefore authorised M. Ader to
take the machine apart and carry it to the camp at Satory so as
to proceed with the trials.

By letter of August 19th the Chairman made report to the Minister
of the findings of the Committee.

The work on the grounds having taken longer than was anticipated,
the Chairman took advantage of this delay to call the Committee
together for a second meeting, during which M. Ader was to run
the two propulsive screws situated at the forward end of the
apparatus.

The meeting was held October 2nd.  It gave the Committee an
opportunity to appreciate the motive power in all its details;
firebox, boiler, engine, under perfect control, absolute
condensation, automatic fuel and feed of the liquid to be
vaporised, automatic lubrication and scavenging; everything, in
a word, seemed well designed and executed.

The weights in comparison with the power of the engine realised
a considerable advance over anything made to date, since the two
engines weighed together realised 42 kg., the firebox and boiler
60 kg., the condenser 15 kg., or a total of 117 kg. for
approximately 40 horse-power or a little less than 3 kg. per
horse-power.

One of the members summed up the general opinion by saying: 
'Whatever may be the result from an aviation point of view, a
result which could not be foreseen for the moment, it was
nevertheless proven that from a mechanical point of view M.
Ader's apparatus was of the greatest interest and real
ingeniosity.  He expressed a hope that in any case the machine
would not be lost to science.'

The second experiment in the workshop was made in the presence
of the Chairman, the purpose being to demonstrate that the
wings, having a spread of 17 metres, were sufficiently strong
to support the weight of the apparatus.  With this object in
view, 14 sliding supports were placed under each one of these,
representing imperfectly the manner in which the wings would
support the machine in the air; by gradually raising the
supports with the slides, the wheels on which the machine rested
were lifted from the ground.  It was evident at that time that
the members composing the skeleton of the wings supported the
apparatus, and it was quite evident that when the wings were
supported by the air on every point of their surface, the stress
would be better equalised than when resting on a few supports,
and therefore the resistance to breakage would be considerably
greater.

After this last test, the work on the ground being practically
finished, the machine was transported to Satory, assembled and
again made ready for trial.

At first M. Ader was to manoeuvre the machine on the ground at
a moderate speed, then increase this until it was possible to
judge whether there was a tendency for the machine to rise; and
it was only after M. Ader had acquired sufficient practice that
a meeting of the Committee was to be called to be present at the
first part of the trials; namely, volutions of the apparatus on
the ground.

The first test took place on Tuesday, October 12th, in the
presence of the Chairman of the Committee.  It had rained a good
deal during the night and the clay track would have offered
considerable resistance to the rolling of the machine;
furthermore, a moderate wind was blowing from the south-west,
too strong during the early part of the afternoon to allow of
any trials. 

Toward sunset, however, the wind having weakened, M. Ader
decided to make his first trial; the machine was taken out of
its hangar, the wings were mounted and steam raised.  M. Ader
in his seat had, on each side of him, one man to the right and
one to the left, whose duty was to rectify the direction of the
apparatus in the event that the action of the rear wheel as a
rudder would not be sufficient to hold the machine in a straight
course.

At 5.25 p.m. the machine was started, at first slowly and then
at an increased speed; after 250 or 300 metres, the two men who
were being dragged by the apparatus were exhausted and forced to
fall flat on the ground in order to allow the wings to pass over
them, and the trip around the track was completed, a total of
1,400 metres, without incident, at a fair speed, which could be
estimated to be from 300 to 400 metres per minute. 
Notwithstanding M. Ader's inexperience, this being the first
time that he had run his apparatus, he followed approximately
the chalk line which marked the centre of the track and he
stopped at the exact point from which he started.

The marks of the wheels on the ground, which was rather soft,
did not show up very much, and it was clear that a part of the
weight of the apparatus had been supported by the wings, though
the speed was only about one-third of what the machine could do
had M. Ader used all its motive power; he was running at a
pressure of from 3 to 4 atmospheres, when he could have used 10
to 12.

This first trial, so fortunately accomplished, was of great
importance; it was the first time that a comparatively heavy
vehicle (nearly 400 kg., including the weight of the operator,
fuel, and water) had been set in motion by a tractive apparatus,
using the air solely as a propelling medium.  The favourable
report turned in by the Committee after the meeting of October
2nd was found justified by the results demonstrated on the
grounds, and the first problem of aviation, namely, the creation
of efficient motive power, could be considered as solved, since
the propulsion of the apparatus in the air would be a great deal
easier than the traction on the ground, provided that the second
part of the problem, the sustaining of the machine in the air,
would be realised.

The next day, Wednesday the 13th, no further trials were made
on account of the rain and wind.

On Thursday the 14th the Chairman requested that General
Grillon, who had just been appointed a member of the Committee,
accompany him so as to have a second witness.

The weather was fine, but a fairly strong, gusty wind was
blowing from the south.  M. Ader explained to the two members
of the Committee the danger of these gusts, since at two points
of the circumference the wind would strike him sideways.  The
wind was blowing in the direction A B, the apparatus starting
from C, and running in the direction shown by the arrow.  The
first dangerous spot would be at B.  The apparatus had been kept
in readiness in the event of the wind dying down.  Toward sunset
the wind seemed to die down, as it had done on the evening of
the 12th.  M. Ader hesitated, which, unfortunately, further
events only justified, but decided to make a new trial.

At the start, which took place at 5.15 p.m., the apparatus,
having the wind in the rear, seemed to run at a fairly regular
speed; it was, nevertheless, easy to note from the marks of the
wheels on the ground that the rear part of the apparatus had been
lifted and that the rear wheel, being the rudder, had not been in
constant contact with the ground.  When the machine came to the
neighbourhood of B, the two members of the Committee saw the
machine swerve suddenly out of the track in a semicircle, lean
over to the right and finally stop.  They immediately proceeded
to the point where the accident had taken place and endeavoured
to find an explanation for the same.  The Chairman finally
decided as follows:

M. Ader was the victim of a gust of wind which he had feared as
he explained before starting out; feeling himself thrown out of
his course, he tried to use the rudder energetically, but at that
time the rear wheel was not in contact with the ground, and
therefore did not perform its function; the canvas rudder, which
had as its purpose the manoeuvring of the machine in the air, did
not have sufficient action on the ground.  It would have been
possible without any doubt to react by using the propellers at
unequal speed, but M. Ader, being still inexperienced, had not
thought of this.  Furthermore, he was thrown out of his course so
quickly that he decided, in order to avoid a more serious
accident, to stop both engines.  This sudden stop produced the
half-circle already described and the fall of the machine on its
side.

The damage to the machine was serious; consisting at first sight
of the rupture of both propellers, the rear left wheel and the
bending of the left wing tip.  It will only be possible to
determine after the machine is taken apart whether the engine,
and more particularly the organs of transmission, have been put
out of line.

Whatever the damage may be, though comparatively easy to repair,
it will take a certain amount of time, and taking into
consideration the time of year it is evident that the tests will
have to be adjourned for the present.

As has been said in the above report, the tests, though
prematurely interrupted, have shown results of great importance,
and though the final results are hard to foresee, it would seem
advisable to continue the trials.  By waiting for the return of
spring there will be plenty of time to finish the tests and it
will not be necessary to rush matters, which was a partial cause
of the accident.  The Chairman of the Committee personally has
but one hope, and that is that a decision be reached accordingly.

     Division General,
            Chairman of the Committee,
                     Mensier.

Boulogne-sur-Seine, October 21st, 1897.

               Annex to the Report of October 21st.

General Grillon, who was present at the trials of the 14th, and
who saw the report relative to what happened during that day,
made the following observations in writing, which are reproduced
herewith in quotation marks.  The Chairman of the Committee does
not agree with General Grillon and he answers theseobservations
paragraph by paragraph.

1.  'If the rear wheel (there is only one of these) left but
intermittent tracks on the ground, does that prove that the
machine has a tendency to rise when running at a certain speed?'

Answer.--This does not prove anything in any way, and I was very
careful not to mention this in my report, this point being
exactly what was needed and that was not demonstrated during the
two tests made on the grounds.

'Does not this unequal pressure of the two pair of wheels on the
ground show that the centre of gravity of the apparatus is
placed too far forward and that under the impulse of the
propellers the machine has a tendency to tilt forward, due to
the resistance of the air?'

Answer.--The tendency of the apparatus to rise from the rear
when it was running with the wind seemed to be brought about by
the effects of the wind on the huge wings, having a spread of 17
metres, and I believe that when the machine would have faced the
wind the front wheels would have been lifted.

During the trials of October 12th, when a complete circuit of
the track was accomplished without incidents, as I and Lieut. 
Binet witnessed, there was practically no wind.  I was therefore
unable to verify whether during this circuit the two front
wheels or the rear wheel were in constant contact with the
ground, because when the trial was over it was dark (it was
5.30) and the next day it was impossible to see anything because
it had rained during the night and during Wednesday morning. 
But what would prove that the rear wheel was in contact with the
ground at all times is the fact that M. Ader, though
inexperienced, did not swerve from the circular track, which
would prove that he steered pretty well with his rear
wheel--this he could not have done if he had been in the air.

In the tests of the 12th, the speed was at least as great as on
the 14th.

2.  'It would seem to me that if M. Ader thought that his rear
wheels were off the ground he should have used his canvas rudder
in order to regain his proper course; this was the best way of
causing the machine to rotate, since it would have given an
angular motion to the front axle.'

Answer.--I state in my report that the canvas rudder whose
object was the manoeuvre of the apparatus in the air could have
no effect on the apparatus on the ground, and to convince
oneself of this point it is only necessary to consider the small
surface of this canvas rudder compared with the mass to be
handled on the ground, a weight of approximately 400 kg. 
According to my idea, and as I have stated in my report, M. Ader
should have steered by increasing the speed on one of his
propellers and slowing down the other.  He admitted afterward
that this remark was well founded, but that he did not have time
to think of it owing to the suddenness of the accident.

3.  'When the apparatus fell on its side it was under the sole
influence of the wind, since M. Ader had stopped the machine. 
Have we not a result here which will always be the same when the
machine comes to the ground, since the engines will always have
to be stopped or slowed down when coming to the ground?  Here
seems to be a bad defect of the apparatus under trial.'

Answer.--I believe that the apparatus fell on its side after
coming to a stop, not on account of the wind, but because the
semicircle described was on rough ground and one of the wheels
had collapsed.                          
                                       Mensier.                   
October 27th, 1897.



                      APPENDIX B

Specification and Claims of Wright Patent, No. 821393.
Filed March 23rd, 1903.  Issued May 22nd, 1906.  Expires May
22nd, 1923.

To all whom it may concern.

Be it known that we, Orville Wright and Wilbur Wright, citizens
of the United States, residing in the city of Dayton, county of
Montgomery, and State of Ohio, have invented certain new and
useful Improvements in Flying Machines, of which the following
is a specification.

Our invention relates to that class of flying-machines in which
the weight is sustained by the reactions resulting when one or
more aeroplanes are moved through the air edgewise at a small
angle of incidence, either by the application of mechanical
power or by the utilisation of the force of gravity.

The objects of our invention are to provide means for
maintaining or restoring the equilibrium or lateral balance of
the apparatus, to provide means for guiding the machine both
vertically and horizontally, and to provide a structure
combining lightness, strength, convenience of construction and
certain other advantages which will hereinafter appear.

To these ends our invention consists in certain novel features,
which we will now proceed to describe and will then particularly
point out in the claims. In the accompanying drawings, Figure I
1 is a perspective view of an apparatus embodying our invention
in one form.  Fig. 2 is a plan view of the same, partly in
horizontal section and partly broken away.  Fig. 3 is a side
elevation, and Figs. 4 and 5 are detail views, of one form of
flexible joint for connecting the upright standards with the
aeroplanes.

In flying machines of the character to which this invention
relates the apparatus is supported in the air by reason of the
contact between the air and the under surface of one or more
aeroplanes, the contact surface being presented at a small angle
of incidence to the air. The relative movements of the air and
aeroplane may be derived from the motion of the air in the form
of wind blowing in the direction opposite to that in which the
apparatus is travelling or by a combined downward and forward
movement of the machine, as in starting from an elevated
position or by combination of these two things, and in either
case the operation is that of a soaring-machine, while power
applied to the machine to propel it positively forward will
cause the air to support the machine in a similar manner.  In
either case owing to the varying conditions to be met there are
numerous disturbing forces which tend to shift the machine from
the position which it should occupy to obtain the desired
results.  It is the chief object of our invention to provide
means for remedying this difficulty, and we will now proceed to
describe the construction by means of which these results are
accomplished.

In the accompanying drawing we have shown an apparatus embodying
our invention in one form.  In this illustrative embodiment the
machine is shown as comprising two parallel superposed
aeroplanes, 1 and 2, may be embodied in a structure having a
single aeroplane. Each aeroplane is of considerably greater width
from side to side than from front to rear.  The four corners of
the upper aeroplane are indicated by the reference letters a, b,
c, and d, while the corresponding corners of the lower aeroplane
2 are indicated by the reference letters e, f, g, and h.  The
marginal lines ab and ef indicate the front edges of the
aeroplanes, the lateral margins of the upper aeroplane are
indicated, respectively, by the lines ad and bc, the lateral
margins of the lower aeroplane are indicated, respectively, by
the lines eh and fg, while the rear margins of the upper and
lower aeroplanes are indicated, respectively, by the lines cd and
gh.

Before proceeding to a description of the fundamental theory of
operation of the structure we will first describe the preferred
mode of constructing the aeroplanes and those portions of the
structure which serve to connect the two aeroplanes.

Each aeroplane is formed by stretching cloth or other suitable
fabric over a frame composed of two parallel transverse spars 3,
extending from side to side of the machine, their ends being
connected by bows 4 extending from front to rear of the machine. 
The front and rear spars 3 of each aeroplane are connected by a
series of parallel ribs 5, which preferably extend somewhat
beyond the rear spar, as shown.  These spars, bows, and ribs are
preferably constructed of wood having the necessary strength,
combined with lightness and flexibility.  Upon this framework
the cloth which forms the supporting surface of the aeroplane is
secured, the frame being enclosed in the cloth.  The cloth for
each aeroplane previous to its attachment to its frame is cut on
the bias and made up into a single piece approximately the size
and shape of the aeroplane, having the threads of the fabric
arranged diagonally to the transverse spars and longitudinal
ribs, as indicated at 6 in Fig. 2.  Thus the diagonal threads of
the cloth form truss systems with the spars and ribs, the threads
constituting the diagonal members.   A hem is formed at the rear
edge of the cloth to receive a wire 7, which is connected to the
ends of the rear spar and supported by the rearwardly-extending
ends of the longitudinal ribs 5, thus forming a
rearwardly-extending flap or portion of the aeroplane. This
construction of the aeroplane gives a surface which has very
great strength to withstand lateral and longitudinal strains, at
the same time being capable of being bent or twisted in the
manner hereinafter described.

When two aeroplanes are employed, as in the construction
illustrated, they are connected together by upright standards 8. 
These standards are substantially rigid, being preferably
constructed of wood and of equal length, equally spaced along
the front and rear edges of the aeroplane, to which they are
connected at their top and bottom ends by hinged joints or
universal joints of any suitable description.  We have shown one
form of connection which may be used for this purpose in Figs. 4
and 5 of the drawings.  In this construction each end of the
standard 8 has secured to it an eye 9 which engages with a hook
10, secured to a bracket plate 11, which latter plate is in
turn fastened to the spar 3.  Diagonal braces or stay-wires 12
extend from each end of each standard to the opposite ends of
the adjacent standards, and as a convenient mode of attaching
these parts I have shown a hook 13 made integral with the hook
10 to receive the end of one of the stay-wires, the other
stay-wire being mounted on the hook 10.  The hook 13 is shown
as bent down to retain the stay-wire in connection to it, while
the hook 10 is shown as provided with a pin 14 to hold the
staywire 12 and eye 9 in position thereon.  It will be seen that
this construction forms a truss system which gives the whole
machine great transverse rigidity and strength, while at the
same time the jointed connections of the parts permit the
aeroplanes to be bent or twisted in the manner which we will now
proceed to describe.

15 indicates a rope or other flexible connection extending
lengthwise of the front of the machine above the lower
aeroplane, passing under pulleys or other suitable guides 16 at
the front corners e and f of the lower aeroplane, and extending
thence upward and rearward to the upper rear corners c and d, of
the upper aeroplane, where they are attached, as indicated at
17.  To the central portion of the rope there is connected a
laterally-movable cradle 18, which forms a means for moving the
rope lengthwise in one direction or the other, the cradle being
movable toward either side of the machine.  We have devised this
cradle as a convenient means for operating the rope 15, and the
machine is intended to be generally used with the operator lying
face downward on the lower aeroplane, with his head to the
front, so that the operator's body rests on the cradle, and the
cradle can be moved laterally by the movements of the operator's
body.  It will be understood, however, that the rope 15 may be
manipulated in any suitable manner.

19 indicates a second rope extending transversely of the
machine along the rear edge of the body portion of the lower
aeroplane, passing under suitable pulleys or guides 20 at the
rear corners g and h of the lower aeroplane and extending thence
diagonally upward to the front corners a and b of the upper
aeroplane, where its ends are secured in any suitable manner, as
indicated at 21.

Considering the structure so far as we have now described it,
and assuming that the cradle 18 be moved to the right in Figs. 
1 and 2, as indicated by the arrows applied to the cradle in
Fig. 1 and by the dotted lines in Fig. 2, it will be seen that
that portion of the rope 15 passing under the guide pulley at
the corner e and secured to the corner d will be under tension,
while slack is paid out throughout the other side or half of the
rope 15.  The part of the rope 15 under tension exercises a
downward pull upon the rear upper corner d of the structure and
an upward pull upon the front lower corner e, as indicated by
the arrows.  This causes the corner d to move downward and the
corner e to move upward.  As the corner e moves upward it
carries the corner a upward with it, since the intermediate
standard 8 is substantially rigid and maintains an equal
distance between the corners a and e at all times.  Similarly,
the standard 8, connecting the corners d and h, causes the
corner h to move downward in unison with the corner d.  Since
the corner a thus moves upward and the corner h moves downward,
that portion of the rope 19 connected to the corner a will be
pulled upward through the pulley 20 at the corner h, and the
pull thus exerted on the rope 19 will pull the corner b on the
other wise of the machine downward and at the same time pull the
corner g at said other side of the machine upward.  This results
in a downward movement of the corner b and an upward movement of
the corner c.  Thus it results from a lateral movement of the
cradle 18 to the right in Fig. 1 that the lateral margins ad
and eh at one side of the machine are moved from their normal
positions in which they lie in the normal planes of their
respective aeroplanes, into angular relations with said normal
planes, each lateral margin on this side of the machine being
raised above said normal plane at its forward end and depressed
below said normal plane at its rear end, said lateral margins
being thus inclined upward and forward.  At the same time a
reverse inclination is imparted to the lateral margins bc end fg
at the other side of the machine, their inclination being
downward and forward. These positions are indicated in dotted
lines in Fig. 1 of the drawings.  A movement of the cradle 18 in
the opposite direction from its normal position will reverse the
angular inclination of the lateral margins of the aeroplanes in
an obvious manner.  By reason of this construction it will be
seen that with the particular mode of construction now under
consideration it is possible to move the forward corner of the
lateral edges of the aeroplane on one side of the machine either
above or below the normal planes of the aeroplanes, a reverse
movement of the forward corners of the lateral margins on the
other side of the machine occurring simultaneously.  During this
operation each aeroplane is twisted or distorted around a line
extending centrally across the same from the middle of one
lateral margin to the middle of the other lateral margin, the
twist due to the moving of the lateral margins to different
angles extending across each aeroplane from side to side, so that
each aeroplane surface is given a helicoidal warp or twist.  We
prefer this construction and mode of operation for the reason
that it gives a gradually increasing angle to the body of each
aeroplane from the centre longitudinal line thereof outward to
the margin, thus giving a continuous surface on each side of the
machine, which has a gradually increasing or decreasing angle of
incidence from the centre of the machine to either side.  We wish
it to be understood, however, that our invention is not limited
to this particular construction, since any construction whereby
the angular relations of the lateral margins of the aeroplanes
may be varied in opposite directions with respect to the normal
planes of said aeroplanes comes within the scope of our
invention.  Furthermore, it should be understood that while the
lateral margins of the aeroplanes move to different angular
positions with respect to or above and below the normal planes of
said aeroplanes, it does not necessarily follow that these
movements bring the opposite lateral edges to different angles
respectively above and below a horizontal plane since the normal
planes of the bodies of the aeroplanes are inclined to the
horizontal when the machine is in flight, said inclination being
downward from front to rear, and while the forward corners on one
side of the machine may be depressed below the normal planes of
the bodies of the aeroplanes said depression is not necessarily
sufficient to carry them below the horizontal planes passing
through the rear corners on that side.  Moreover, although we
prefer to so construct the apparatus that the movements of the
lateral margins on the opposite sides of the machine are equal in
extent and opposite m direction, yet our invention is not limited
to a construction producing this result, since it may be
desirable under certain circumstances to move the lateral margins
on one side of the machine just described without moving the
lateral margins on the other side of the machine to an equal
extent in the opposite direction.  Turning now to the purpose of
this provision for moving the lateral margins of the aeroplanes
in the manner described, it should be premised that owing to
various conditions of wind pressure and other causes the body of
the machine is apt to become unbalanced laterally, one side
tending to sink and the other side tending to rise, the machine
turning around its central longitudinal axis.  The  provision
which we have just described enables the operator to meet this
difficulty and preserve the lateral balance of the machine. 
Assuming that for some cause that side of the machine which lies
to the left of the observer in Figs. 1 and 2 has shown a
tendency to drop downward, a movement of the cradle 18 to the
right of said figures, as herein before assumed, will move the
lateral margins of the aeroplanes in the manner already
described, so that the margins ad and eh will be inclined
downward and rearward, and the lateral margins bc and fg will be
inclined upward and rearward with respect to the normal planes
of the bodies of the aeroplanes.  With the parts of the machine
in this position it will be seen that the lateral margins ad
and eh present a larger angle of incidence to the resisting
air, while the lateral margins on the other side of the machine
present a smaller angle of incidence.  Owing to this fact, the
side of the machine presenting the larger angle of incidence
will tend to lift or move upward, and this upward movement will
restore the lateral balance of the machine.  When the other side
of the machine tends to drop, a movement of the cradle 18 in the
reverse direction will restore the machine to its normal lateral
equilibrium.  Of course, the same effect will be produced in the
same way in the case of a machine employing only a single
aeroplane.

In connection with the body of the machine as thus operated we
employ a vertical rudder or tail 22, so supported as to turn
around a vertical axis.  This rudder is supported at the rear
ends on supports or arms 23, pivoted at their forward ends to
the rear margins of the upper and lower aeroplanes, respectively. 
These supports are preferably V-shaped, as shown, so that their
forward ends are comparatively widely separated, their pivots
being indicated at 24.  Said supports are free to swing upward at
their free rear ends, as indicated in dotted lines in Fig. 3,
their downward movement being limited in any suitable manner. 
The vertical pivots of the rudder 22 are indicated at 25, and one
of these pivots has mounted thereon a sheave or pulley 26, around
which passes a tiller-rope 27, the ends of which are extended out
laterally and secured to the rope 19 on opposite sides of the
central point of said rope.  By reason of this construction the
lateral shifting of the cradle 18 serves to turn the rudder to
one side or the other of the line of flight.  It will be observed
in this connection that the construction is such that the rudder
will always be so turned as to present its resisting surface on
that side of the machine on which the lateral margins of the
aeroplanes present the least angle of resistance.  The reason of
this construction is that when the lateral margins of the
aeroplanes are so turned in the manner hereinbefore described as
to present different angles of incidence to the atmosphere, that
side presenting the largest angle of incidence, although being
lifted or moved upward in the manner already described, at the
same time meets with an increased resistance to its forward
motion, while at the same time the other side of the machine,
presenting a smaller angle of incidence, meets with less
resistance to its forward motion and tends to move forward more
rapidly than the retarded side.  This gives the machine a
tendency to turn around its vertical axis, and this tendency if
not properly met will not only change the direction of the front
of the machine, but will ultimately permit one side thereof to
drop into a position vertically below the other side with the
aero planes in vertical position, thus causing the machine to
fall.  The movement of the rudder, hereinbefore described,
prevents this action, since it exerts a retarding influence on
that side of the machine which tends to move forward too rapidly
and keeps the machine with its front properly presented to the
direction of flight and with its body properly balanced around
its central longitudinal axis.  The pivoting of the supports 23
so as to permit them to swing upward prevents injury to the
rudder and its supports in case the machine alights at such an
angle as to cause the rudder to strike the ground first, the
parts yielding upward, as indicated in dotted lines in Fig. 3,
and thus preventing injury or breakage.  We wish it to be
understood, however, that we do not limit ourselves to the
particular description of rudder set forth, the essential being
that the rudder shall be vertical and shall be so moved as to
present its resisting surface on that side of the machine which
offers the least resistance to the atmosphere, so as to
counteract the tendency of the machine to turn around a vertical
axis when the two sides thereof offer different resistances to
the air.

From the central portion of the front of the machine struts 28
extend horizontally forward from the lower aeroplane, and struts
29 extend downward and forward from the central portion of the
upper aeroplane, their front ends being united to the struts 28,
the forward extremities of which are turned up, as indicated at
30.  These struts 28 and 29 form truss-skids projecting in front
of the whole frame of the machine and serving to prevent the
machine from rolling over forward when it alights.  The struts 29
serve to brace the upper portion of the main frame and resist its
tendency to move forward after the lower aeroplane has been
stopped by its contact with the earth, thereby relieving the rope
19 from undue strain, for it will be understood that when the
machine comes into contact with the earth, further forward
movement of the lower portion thereof being suddenly arrested,
the inertia of the upper portion would tend to cause it to
continue to move forward if not prevented by the struts 29, and
this forward movement of the upper portion would bring a very
violent strain upon the rope 19, since it is fastened to the
upper portion at both of its ends, while its lower portion is
connected by the guides 20 to the lower portion.  The struts 28
and 29 also serve to support the front or horizontal rudder, the
construction of which we will now proceed to describe.

The front rudder 31 is a horizontal rudder having a flexible
body, the same consisting of three stiff crosspieces or sticks
32, 33, and 34, and the flexible ribs 35, connecting said
cross-pieces and extending from front to rear.  The frame thus
provided is covered by a suitable fabric stretched over the same
to form the body of the rudder.  The rudder is supported from
the struts 29 by means of the intermediate cross-piece 32, which
is located near the centre of pressure slightly in front of a
line equidistant between the front and rear edges of the rudder,
the cross-piece 32 forming the pivotal axis of the rudder, so as
to constitute a balanced rudder.  To the front edge of the
rudder there are connected springs 36 which springs are
connected to the upturned ends 30 of the struts 28, the
construction being such that said springs tend to resist any
movement either upward or downward of the front edge of the
horizontal rudder.  The rear edge of the rudder lies immediately
in front of the operator and may be operated by him in any
suitable manner.  We have shown a mechanism for this purpose
comprising a roller or shaft 37, which may be grasped by the
operator so as to turn the same in either direction.  Bands 38
extend from the roller 37 forward to and around a similar roller
or shaft 39, both rollers or shafts being supported in suitable
bearings on the struts 28.  The forward roller or shaft has
rearwardly-extending arms 40, which are connected by links 41
with the rear edge of the rudder 31.  The normal position of the
rudder 31 is neutral or substantially parallel with the
aeroplanes 1 and 2; but its rear edge may be moved upward or
downward, so as to be above or below the normal plane of said
rudder through the mechanism provided for that purpose.  It will
be seen that the springs 36 will resist any tendency of the
forward edge of the rudder to move in either direction, so that
when force is applied to the rear edge of said rudder the
longitudinal ribs 35 bend, and the rudder thus presents a
concave surface to the action of the wind either above or below
its normal plane, said surface presenting a small angle of
incidence at its forward portion and said angle of incidence
rapidly increasing toward the rear.  This greatly increases the
efficiency of the rudder as compared with a plane surface of
equal area.  By regulating the pressure on the upper and lower
sides of the rudder through changes of angle and curvature in
the manner described a turning movement of the main structure
around its transverse axis may be effected, and the course of
the machine may thus be directed upward or downward at the will
of the operator and the longitudinal balance thereof maintained.

Contrary to the usual custom, we place the horizontal rudder in
front of the aeroplanes at a negative angle and employ no
horizontal tail at all.  By this arrangement we obtain a forward
surface which is almost entirely free from pressure under
ordinary conditions of flight, but which even if not moved at
all from its original position becomes an efficient
lifting-surface whenever the speed of the machine is
accidentally reduced very much below the normal, and thus
largely counteracts that backward travel of the centre of
pressure on the aeroplanes which has frequently been productive
of serious injuries by causing the machine to turn downward and
forward and strike the ground head-on.  We are aware that a
forward horizontal rudder of different construction has been
used in combination with a supporting surface and a rear
horizontal-rudder; but this combination was not intended to
effect and does not effect the object which we obtain by the
arrangement hereinbefore described.

We have used the term 'aeroplane' in this specification and the
appended claims to indicate the supporting surface or supporting
surfaces by means of which the machine is sustained in the air,
and by this term we wish to be understood as including any
suitable supporting surface which normally is substantially
flat, although.  Of course, when constructed of cloth or other
flexible fabric, as we prefer to construct them, these surfaces
may receive more or less curvature from the resistance of the
air, as indicated in Fig. 3.

We do not wish to be understood as limiting ourselves strictly
to the precise details of construction hereinbefore described
and shown in the accompanying drawings, as it is obvious that
these details may be modified without departing from the
principles of our invention.  For instance, while we prefer the
construction illustrated in which each aeroplane is given a
twist along its entire length in order to set its opposite
lateral margins at different angles, we have already pointed out
that our invention is not limited to this form of construction,
since it is only necessary to move the lateral marginal
portions, and where these portions alone are moved only those
upright standards which support the movable portion require
flexible connections at their ends.

Having thus fully described our invention, what we claim as new,
and desire to secure by Letters Patent, is:--

1.  In a flying machine, a normally flat aeroplane having
lateral marginal portions capable of movement to different
positions above or below the normal plane of the body of the
aeroplane, such movement being about an axis transverse to the
line of flight, whereby said lateral marginal portions may be
moved to different angles relatively to the normal plane of the
body of the aeroplane, so as to present to the atmosphere
different angles of incidence, and means for so moving said
lateral marginal portions, substantially as described.

2.  In a flying machine, the combination, with two normally
parallel aeroplanes, superposed the one above the other, of
upright standards connecting said planes at their margins, the
connections between the standards and aeroplanes at the lateral
portions of the aeroplanes being by means of flexible joints,
each of said aeroplanes having lateral marginal portions capable
of movement to different positions above or below the normal
plane of the body of the aeroplane, such movement being about an
axis transverse to the line of flight, whereby said lateral
marginal portions may be moved to different angles relatively to
the normal plane of the body of the aeroplane, so as to present
to the atmosphere different angles of incidence, the standards
maintaining a fixed distance between the portions of the
aeroplanes which they connect, and means for imparting such
movement to the lateral marginal portions of the aeroplanes,
substantially as described.

3.  In a flying machine, a normally flat aeroplane having
lateral marginal portions capable of movement to different
positions above or below the normal plane of the body of the
aeroplane, such movement being about an axis transverse to the
line of flight, whereby said lateral marginal portions may be
moved to different angles relatively to the normal plane of the
body of the aeroplane, and also to different angles relatively
to each other, so as to present to the atmosphere different
angles of incidence, and means for simultaneously imparting such
movement to said lateral marginal portions, substantially as
described.

4.  In a flying machine, the combination, with parallel
superposed aeroplanes, each having lateral marginal portions
capable of movement to different positions above or below the
normal plane of the body of the aeroplane, such movement being
about an axis transverse to the line of flight, whereby said
lateral marginal portions may be moved to different angles
relatively to the normal plane of the body of the aeroplane, and
to different angles relatively to each other, so as to present
to the atmosphere different angles of incidence, of uprights
connecting said aeroplanes at their edges, the uprights
connecting the lateral portions of the aeroplanes being
connected with said aeroplanes by flexible joints, and means for
simultaneously imparting such movement to said lateral marginal
portions, the standards maintaining a fixed distance between the
parts which they connect, whereby the lateral portions on the
same side of the machine are moved to the same angle,
substantially as described.

5.  In a flying machine, an aeroplane having substantially the
form of a normally flat rectangle elongated transversely to the
line of flight, in combination which means for imparting to the
lateral margins of said aeroplane a movement about an axis lying
in the body of the aeroplane perpendicular to said lateral
margins, and thereby moving said lateral margins into different
angular relations to the normal plane of the body of the
aeroplane, substantially as described.

6.  In a flying machine, the combination, with two superposed
and normally parallel aeroplanes, each having substantially the
form of a normally flat rectangle elongated transversely to the
line of flight, of upright standards connecting the edges of
said aeroplanes to maintain their equidistance, those standards
at the lateral portions of said aeroplanes being connected
therewith by flexible joints, and means for simultaneously
imparting to both lateral margins of both aeroplanes a movement
about axes which are perpendicular to said margins and in the
planes of the bodies of the respective aeroplanes, and thereby
moving the lateral margins on the opposite sides of the machine
into different angular relations to the normal planes of the
respective aeroplanes, the margins on the same side of the
machine moving to the same angle, and the margins on one side of
the machine moving to an angle different from the angle to which
the margins on the other side of the machine move, substantially
as described.

7.  In a flying machine, the combination, with an aeroplane, and
means for simultaneously moving the lateral portions thereof
into different angular relations to the normal plane of the body
of the aeroplane and to each other, so as to present to the
atmosphere different angles of incidence, of a vertical rudder,
and means whereby said rudder is caused to present to the wind
that side thereof nearest the side of the aeroplane having the
smaller angle of incidence and offering the least resistance to
the atmosphere, substantially as described.

8.  In a flying machine, the combination, with two superposed
and normally parallel aeroplanes, upright standards connecting
the edges of said aeroplanes to maintain their equidistance,
those standards at the lateral portions of said aeroplanes being
connected therewith by flexible joints, and means for
simultaneously moving both lateral portions of both aeroplanes
into different angular relations to the normal planes of the
bodies of the respective aeroplanes, the lateral portions on one
side of the machine being moved to an angle different from that
to which the lateral portions on the other side of the machine
are moved, so as to present different angles of incidence at the
two sides of the machine, of a vertical rudder, and means
whereby said rudder is caused to present to the wind that side
thereof nearest the side of the aeroplanes having the smaller
angle of incidence and offering the least resistance to the
atmosphere, substantially as described.

9.  In a flying machine, an aeroplane normally flat and
elongated transversely to the line of flight, in combination
with means for imparting to said aeroplane a helicoidal warp
around an axis transverse to the line of flight and extending
centrally along the body aeroplane in the direction of the
elongation aeroplane, substantially as described.

10.  In a flying machine, two aeroplanes, each normally flat and
elongated transversely to the line of flight, and upright
standards connecting the edges of said aeroplanes to maintain
their equidistance, the connections between said standards and
aeroplanes being by means of flexible joints, in combination
with means for simultaneously imparting to each of said
aeroplanes a helicoidal warp around an axis transverse to the
line of flight and extending centrally along the body of the
aeroplane in the direction of the aeroplane, substantially as
described.

11.   In a flying machine, two aeroplanes, each normally flat
and elongated transversely to the line of flight, and upright
standards connecting the edges of said aeroplanes to maintain
their equidistance, the connections between such standards and
aeroplanes being by means of flexible joints, in combination
with means for simultaneously imparting to each of said
aeroplanes a helicoidal warp around an axis transverse to the
line of flight and extending centrally along the body of the
aeroplane in the direction of the elongation of the
aeroplane, a vertical rudder, and means whereby said rudder is
caused to present to the wind that side thereof nearest the side
of the aeroplanes having the smaller angle of incidence and
offering the least resistance to the atmosphere, substantially
as described.

12.  In a flying machine, the combination, with an aeroplane, of
a normally flat and substantially horizontal flexible rudder,
and means for curving said rudder rearwardly and upwardly or
rearwardly and downwardly with respect to its normal plane,
substantially as described.

13.  In a flying machine, the combination, with an aeroplane, of
a normally flat and substantially horizontal flexible rudder
pivotally mounted on an axis transverse to the line of flight
near its centre, springs resisting vertical movement of the
front edge of said rudder, and means for moving the rear edge of
said rudder, above or below the normal plane thereof,
substantially as described.

14.  A flying machine comprising superposed connected aeroplanes
means for moving the opposite lateral portions of said
aeroplanes to different angles to the normal planes thereof, a
vertical rudder, means for moving said vertical rudder toward
that side of the machine presenting the smaller angle of
incidence and the least resistance to the atmosphere, and a
horizontal rudder provided with means for presenting its upper
or under surface to the resistance of the atmosphere,
substantially as described.

15.  A flying machine comprising superposed connected
aeroplanes, means for moving the opposite lateral portions of
said aeroplanes to different angles to the normal planes
thereof, a vertical rudder, means for moving said vertical
rudder toward that side of the machine presenting the smaller
angle of incidence and the least resistance to the atmosphere,
and a horizontal rudder provided with means for presenting its
upper or under surface to the resistance of the atmosphere, said
vertical rudder being located at the rear of the machine and
said horizontal rudder at the front of the machine,
substantially as described.

16.  In a flying machine, the combination, with two superposed
and connected aeroplanes, of an arm extending rearward from each
aeroplane, said arms being parallel and free to swing upward at
their rear ends, and a vertical rudder pivotally mounted in the
rear ends of said arms, substantially as described.

17.  A flying machine comprising two superposed aeroplanes,
normally flat but flexible, upright standards connecting the
margins of said aeroplanes, said standards being connected to
said aeroplanes by universal joints, diagonal stay-wires
connecting the opposite ends of the adjacent standards, a rope
extending along the front edge of the lower aeroplane, passing
through guides at the front corners thereof, and having its ends
secured to the rear corners of the upper aeroplane, and a rope
extending along the rear edge of the lower aeroplane, passing
through guides at the rear corners thereof, and having its ends
secured to the front corners of the upper aeroplane,
substantially as described.

18.  A flying machine comprising two superposed aeroplanes,
normally flat but flexible, upright standards connecting the
margins of said aeroplanes, said standards being connected to
said aeroplanes by universal joints, diagonal stay-wires
connecting the opposite ends of the adjacent standards, a rope
extending along the front edge of the lower aeroplane, passing
through guides at the front corners thereof, and having its ends
secured to the rear corners of the upper aeroplane, and a rope
extending along the rear edge of the lower aeroplane, passing
through guides at the rear corners thereof, and having its ends
secured to the front corners of the upper aeroplane, in
combination with a vertical rudder, and a tiller-rope connecting
said rudder with the rope extending along the rear edge of the
lower aeroplane, substantially as described.
                              ORVILLE WRIGHT.
                              WILBUR WRIGHT.
Witnesses:
Chas. E. Taylor. 
E. Earle Forrer.



                      APPENDIX C

Proclamation published by the French Government on balloon
ascents, 1783.

       NOTICE TO THE PUBLIC! PARIS, 27TH AUGUST, 1783.

On the Ascent of balloons or globes in the air.  The one
in question has been raised in Paris this day, 27th August,
1783, at 5 p.m., in the Champ de Mars.

A Discovery has been made, which the Government deems it right to
make known, so that alarm be not occasioned to the people.

On calculating the different weights of hot air, hydrogen gas,
and common air, it has been found that a balloon filled with
either of the two former will rise toward heaven till it is in
equilibrium with the surrounding air, which may not happen until
it has attained a great height.

The first experiment was made at Annonay, in Vivarais, MM.
Montgolfier, the inventors; a globe formed of canvas and paper,
105 feet in circumference, filled with heated air, reached an
uncalculated height.  The same experiment has just been renewed
in Paris before a great crowd.  A globe of taffetas or light
canvas covered by elastic gum and filled with inflammable air,
has risen from the Champ de Mars, and been lost to view in the
clouds, being borne in a north-westerly direction.  One cannot
foresee where it will descend.

It is proposed to repeat these experiments on a larger scale. 
Any one who shall see in the sky such a globe, which resembles
'la lune obscurcie,' should be aware that, far from being an
alarming phenomenon, it is only a machine that cannot possibly
cause any harm, and which will some day prove serviceable to the
wants of society.

(Signed) DE SAUVIGNY.
LENOIR.





End Project Gutenberg Etext of A History of Aeronautics