There are few outstanding events in the _A History of Aeronautics（#874）

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

There are few outstanding events in the development of aeronautics