In 1880, Mr. Thomas A. Edison, at Menlo Park, New Jersey, perfected a

series of electric-railway motors and locomotives that were actually

employed in hauling freight and passengers. The following year Mr.

Edison made a contract with Mr. Henry Villard, which stipulated that

the inventor was to construct an electric railway at least two miles

and a half in length, which was to be equipped with two locomotives

and three cars, one locomotive for freight and one for passengers, the

passenger locomotive to have a capacity of sixty miles an hour. It

was agreed that if the experiment with this railway proved successful

Mr. Villard was to reimburse Mr. Edison for the actual outlay, and to

install at least fifty miles of electric road in the wheat regions of

the Northwest.

The electric locomotives built by Mr. Edison were constructed along the

usual lines of steam locomotives, with cab, headlight, and cowcatcher,

the motive power being applied from the motors to the axle by means

of friction pulleys. This method was soon abandoned, as the pulleys

slipped a great deal before the locomotive actually started. A system

of belts which was substituted proved more satisfactory. The current

was conveyed to the motor through the track, and was supplied to

the road by underground cables connecting from the dynamo-room of

Mr. Edison's laboratory. The rails were insulated from the ties by

coatings of Japan varnish, and by placing them on pads made of muslin

impregnated with tar.

From the very first this road gave promise of success. The tireless

genius of Edison was constantly finding and correcting defects,

and there was every prospect that in a few months a practical and

economical electric railway would be an accomplished fact. Then came

the financial crash of the Northern Pacific Railway, involving the

fortune of Mr. Villard, and tying the hands of the inventor at Menlo

Park for the time being.

The year following, however, Mr. Field and Mr. Edison combined their

forces and formed a company for perfecting and constructing electric

locomotives and railways. In the same year an electric railway was put

in operation at the Chicago Railway Exposition, the chief promoters of

this enterprise being Messrs. Field, F. B. Rae, and C. O. Mailloux. In

the gallery of the building a circular track, something like a third

of a mile in length, was laid, and on this an electric locomotive

named _The Judge_ hauled a single car which carried over twenty-six

thousand passengers in the month of June. In the autumn of the same

year, _The Judge_ was used for hauling passengers on a track at the

Louisville Exposition. It was capable of attaining a speed of twelve

miles an hour, and its average speed was eight miles. It was twelve

feet long over all, weighed something like three tons, and, like

Edison's locomotive, was equipped with cowcatcher, headlight, and cab.

The current was taken from a surface, or feed rail, by means of bundles

of phosphor-bronze wire, so arranged that a good clean contact would

be made on each side of the rail whether the car was moving forward or

backward.

THIRD RAILS AND TROLLEYS

At the same time an Englishman named Leo Daft, then living in America,

was making some important experiments with motors for the purpose

of driving machinery, these motors being operated from central

power-stations located at distant points. Mr. Daft constructed an

electric locomotive, and in November, 1883, constructed what was known

as the Saratoga and Mount MacGregor Railroad. This railroad was twelve

miles in length and included many steep grades. The locomotive, which

hauled a regular passenger-car, received the current from a central

rail. The year following Mr. Daft built and equipped a small road on

one of the long piers of Coney Island, which carried something like

forty thousand passengers in one season. It was an improvement over

the Siemens electric railway established in Germany in 1881--which,

however, was the first road ever established.

The following year the inventor began the equipment of the Baltimore

Union Passenger Railway Company, a line that ran a distance of about

two miles and reached an elevation of one hundred and fifty feet

above the city of Baltimore. This road was put into regular operation

in 1886, and was the second electric street railway in America for

carrying on regular passenger service.

The Baltimore Union Railway had several novel and important features,

one of them being the equipment of part of the line with an

overhead-trolley service, the practical importance of which had been

demonstrated shortly before by Van Depoele. The projector, Mr. Daft,

also built several other lines in different parts of the country,

constantly improving upon his earlier efforts, sometimes using two

overhead trolley wires, with two trolley contacts, thus doing away with

the use of the track as a means of current supply, or for use as part

of the circuit. Although in recent years double overhead trolleys have

largely disappeared, some of them are still in use both in America and

in Europe.

Van Depoele was a Belgian who had come to America in 1869. Although

primarily a cabinet-maker, he had a great liking for the study of

electricity, and devoted all his spare time and money to efforts to

solve the problem of practical street-car propulsion. In 1883, at the

Industrial Exposition at Chicago, he operated a car by electricity,

using an overhead-trolley system somewhat similar to Daft's. By 1885,

he had made sufficient progress to construct a line one mile long for

carrying passengers from the railway station to the Annual Exhibition

grounds at Toronto, Canada. On a single track he operated three cars

and a motor, carrying an average of ten thousand passengers daily,

his train sometimes attaining a speed of thirty miles an hour. For

receiving the current he used an underrunning trolley and pole very

similar to the form now in common use, this being one of the first

instances of employing this particular method of receiving the current.

In this system an insulated track was used for returning the current.

Van Depoele's next venture was the equipment of an electric railway

at South Bend, Indiana, on which five separate cars were operated at

one time--a thing supposed by many to be impossible. The cars of this

road were equipped with motors placed under the cars instead of above

them, thus saving valuable seating-space. In place of the underrunning

trolley and pole, however, the current was taken from the overhead

wire by means of a flexible cable. Later Van Depoele invented an

underrunning trolley and pole, taking out the original patents. His

claims to priority were contested eventually, but they were sustained

by the United States courts.

At this time there were at least a score of inventors whose work added

something of importance to the solution of the problem of electric

traction. But without belittling others, it is probably only justice

to say that the work of Frank J. Sprague, a one-time lieutenant in

the United States Navy, marks the beginning of the modern era of

street railways. In 1888, after a period of struggle and a series of

disheartening disasters, Mr. Sprague and his associates opened an

electric line for the Union Passenger Railway of Richmond, Va., which

"forms a landmark in the history of this industrial development." Over

a line of road with grades at that time considered impossible, thirty

cars were put into use at the same time, the contract for the equipment

calling for its completion in ninety days. The success of this

enterprise, when on the opening day more electric cars were operated

than in all the rest of America together, settled forever the question

of the practicality of electric street railways, as well as many of

the questions of the practical application of the current, thanks to

Sprague's inventive genius.

This road was an overhead trolley-wire system, with an underrunning

trolley held in place by the now-familiar trolley pole. The number

of difficulties that had to be solved in perfecting this apparently

simple piece of apparatus is shown by the statement of Mr. Sprague that

"probably not less than fifty modifications of trolley wheels and poles

were used before what is known as the 'universal movement' type was

adopted."

In this connection the origin of the word "trolley" is interesting. It

seems to have been corrupted from the word "troller" by the workmen of

a Kansas City car-line. On this line an overhead wire was used, the

travelling carriage taking the current from the wire being known as

the "troller." The employees of the road, however, shortly corrupted

"troller" into "trolley"; and "trolley" it has remained ever since.

As in the case of Van Depoele, whose perfection of the underrunning

trolley was contested legally, Sprague's great contribution to electric

traction, the suspension of the motor directly upon the axle, had

finally to be sustained by the United States courts. Sprague's method

was to hang the motor under the car directly upon the axle, by an

extension or solid bearing attached directly to the motor. This plan

of constructing the motor, together with numerous other improvements,

principally in the direction of lightness, simplicity, and

adaptability, soon superseded all pre-existing methods of construction.

Thus Van Depoele's method of taking the current from the wire, and

Sprague's method of utilizing it in the propulsion of the car, must be

regarded as epoch-marking steps in the history of electric traction.

Sprague's invention demonstrated the validity of his contention, now

universally accepted, that motors should be placed under each car

instead of being used on locomotives.

STORAGE-BATTERY SYSTEMS

From the earliest attempts at solving the question of electric

traction, efforts were made to produce some form of storage battery

whereby the cars might be made independent of a distant generating

plant. The advantages of a self-contained vehicle are so obvious that

it is not surprising to find the inventors persistent in their attempts

at producing practical cars of this type. Such battery cars would not

require the dangerous, expensive, and cumbrous system of overhead

wires, or the more sightly but also more expensive system of conduits.

With such a system of cars the elaborate mains and feeders for bringing

the current to the track from the power-house, and for effecting the

return circuit, could be dispensed with. Moreover, the independent

action of such cars over a system where the power is furnished from a

single source, where the stoppage of the current stops every car along

the line, is inestimable.

Between the years 1880 and 1883 many storage-battery cars were built

and put in service both in European and American cities. Probably the

most important one of these lines was that which was built by the

Belgian, Mr. E. Julien, in New York city, in 1887-8. On the Fourth

Avenue road something like a dozen storage-battery cars were put in

operation for a considerable time, and later, improved modifications

of these cars were operated in Philadelphia under the direction of Mr.

Anthony Rackenzaun, of Vienna. But despite the apparent simplicity of

the storage-battery idea, innumerable difficulties were perpetually

presenting themselves in its practical application. Despite the

disheartening results, however, storage-battery cars were not entirely

abandoned in practice until 1903, New York city being the last to

surrender, as it had been about the last to adopt them.

But in February, 1910, the storage-battery street car again made

its appearance on trial in New York--not the old heavy type of

unsatisfactory car, but an entirely new and lighter creation of Thomas

A. Edison, who had been striving for years to solve the storage-battery

problem. This car, which had been tested on the Orange, New Jersey,

street-car line on January 20th, 1910, maintained a speed of fifteen

miles an hour in actual practice, and ran a distance of about one

hundred and fifty miles without re-charging the batteries.

There are some novel features about the car itself, but the

all-important one is the peculiar and novel storage battery which it

has taken Mr. Edison some nine years to perfect. In an imperfect form

this battery was given a trial in 1903, and much was expected of it

because it was not only lighter than the usual form of storage battery,

but it promised more permanency because an alkali was used in place of

an acid as an electrolyte.

In this battery the positive element, which consisted of nickel oxide

interspersed with layers of graphite, was packed in perforated nickel

tubes. The negative element was iron oxide, with potassium hydrate as

the electrolyte. This battery showed no bad effects from over-charging

or from being rapidly discharged, but it was found that the graphite

soon became oxidized and interfered with the working of the battery.

This defect was corrected by substituting chemically pure nickel for

the graphite, but another was soon discovered. Under the pressure

of the oxide of nickel the square tubes containing the nickel were

frequently injured so that the powdered nickel oxide was sifted down on

the pure nickel layers and insulated them.

The only solution of this difficulty seemed to be to pack the nickel

in strong round tubes four inches long and about the size of a lead

pencil, the sides of the tubes being finely perforated. But the expense

of producing such tubes by ordinary methods was prohibitive. A machine

was finally invented, however, which made the tubes economically

by using spirally wound ribbons of metal, the edges being fastened

together during the coiling process. By the use of these tubes the

battery was so far perfected that it was given extensive trials in

1908 on electric vehicles; and as these tests proved satisfactory,

Mr. Edison began the construction of a specially designed street

car equipped with two 5-horse-power 110-volt motors of very light

construction. The car weighs complete about five tons, and the

batteries are stored under the seats running along each side.

This car was tested continuously for three weeks on one of the New

York cross-town lines and performed its work so satisfactorily and

economically that the management of the line decided to give the

system a permanent trial. The regular daily run of this car averaged

something over sixty-six miles, but this by no means exhausted the

capacity of the batteries; and it is estimated that it could easily

have run at least one-quarter farther without re-charging. The

surprising feature of these tests was the low cost of running. The

total cost of electric power for the day's run was about thirty cents,

or 4.3 mills for each mile. The ordinary New York street car costs on

an average about five cents per mile for electrical energy; but on the

other hand, the carrying capacity of these cars is almost twice that of

the Edison car.

The actual cost of running the car, however, was only one of its many

advantages. The fact that no underground conduits have to be laid

or overhead wires erected and maintained makes the initial cost of

installing the line far less than by any other system. The reduction in

the cost of maintenance of the line is also an important item, as it is

estimated that the cost of repairs on conduit lines is about $15,000

annually per mile.

But the most convincing proof that Mr. Edison has really produced a

practical storage battery car lies in the fact that, after testing his

car for three weeks in actual traffic, the managers of the street-car

line ordered sixteen similar cars for operation over their road.

MONORAIL SYSTEMS

The introduction of electricity facilitated the construction of

monorail systems of roads, which had long been the dream of railroad

constructors, since this power could be applied with so much more

flexibility. The defects of the parallel rail system are apparent both

in construction of the roadbed and the operating of trains. It is

almost impossible to lay and maintain the rails in exact parallels,

and even more difficult to keep each rail at the proper height at all

points. Both these factors enter very largely into the determination

of the speed that a train can make over such tracks, any very

great variation from the parallel causing derailment, while slight

depressions or elevations of either rail cause violent and dangerous

rocking of the cars travelling at high speed.

In any monorail system the first of these difficulties, the deviation

of the rail from the parallel, is, of course, eliminated; and it is

found that on a single rail the elevations and depressions are not

serious obstacles. Moreover, the cost of construction of a single-rail

track must obviously be less than for a double-rail track, and the

power necessary to operate cars over such a track far less. But until

the invention of the gyrocar (which is referred to at length in the

following chapter) the methods of balancing the car on a single rail

presented difficulties which quite offset the advantages of the

monorail system. Some of these methods are unique and a few of them are

practical in actual operation.

In Germany a suspension monorail system is in operation, the cars being

suspended from an overhead track. But obviously such a system, which

requires elaborate and expensive steel trestle-work along every fork of

the road, is not adapted to the use of long-distance roads except in

thickly populated districts. A less expensive and highly satisfactory

system is the one invented by Mr. Howard Hansel Tunis and used at the

Jamestown Exhibition in 1907.

In this system the wheels, arranged in tandem, have double flanges

which keep them on the single-rail track, and the cars are prevented

from toppling over by overhead guides. These guides must be supported

on a frame-work, but as there is little tendency to sway on a

single-rail track, they can be relatively light structures. It is the

cost of these frames, however, that practically offsets the low cost

of road-bed construction, so that, everything considered, the mere

matter of initial cost has no very great advantage over the ordinary

double-rail road. But the cost of operating is considerably less than

the older type, and this road would undoubtedly come rapidly into

popularity but for the fact that such gyrocars as the ones invented

in England and Germany are self-sustaining on the rail, doing away

with the expensive overhead frame-work construction, and are likely to

become practical factors in the problem of transportation.

In 1909 an electric aerial monorail up the Wetterhorn in the Alps was

put into operation. On this line a car suspended on two cables, one

above the other and without supports except at the upper and lower

terminals, rises at an angle of forty-five degrees through a distance

of 1,250 feet. There are two sets of these cables, each carrying a car

so arranged as to work in alternate directions simultaneously, this

counter-balancing effecting a great saving in power. The power-plant

is located at the upper end of the ascent, and consists of winding

drums actuated by electricity which raise and lower the cars by means

of cables. On the cars themselves, therefore, there is no power, but

each car is equipped with brakes powerful enough to stop and hold it

notwithstanding the steepness of the incline.

There is nothing particularly novel in the principles involved in this

aerial road, but it is the first of its kind to be built for passenger

traffic. Similar less pretentious roads have been in use for freight

transportation for several years. But the success of this road means

the building of others on inaccessible mountain inclines where the

laying of ordinary roadbeds is out of the question, and the operating

of cog roads too expensive.

VII

THE GYROCAR

On the 8th of May, 1907, Mr. Louis Brennan exhibited, at a _soirée_ of

the Royal Society in London, a remarkable piece of mechanism, which

stirred the imagination of every beholder, and--next morning--as

reported by the newspapers, aroused the amazed interest of the world.

This invention consists of a car run on a single rail, standing erect

like a bicycle when in motion; but, unlike the bicycle, being equally

stable when at rest.

It is a car that could cross the gorge of Niagara on a tight-rope,

like Blondin himself, but with far greater security; a car that shows

many strange properties, seeming to defy not gravitation alone but the

simplest laws of motion. For example, if a weight is placed on one edge

of the car that side rises higher instead of being lowered.

If you push against the side with your hand, the mysterious

creature--you feel that it must be endowed with life--is actually felt

to push back as if resenting the affront.

Similarly, if the wind blows against the car, it veers over toward the

wind. If the track on which it runs--consisting of an ordinary gas-pipe

or of a cable of wire--is curved, even very sharply, the car follows

the curve without difficulty, and, in defiance of ordinary laws of

motion, actually leans inward as a bicycle rider leans under the same

circumstances, instead of being careened outward as one might expect.

A curious mechanism, surely, this new car, with its four wheels set in

line, bicycle fashion, running thus steadily. But strangest of all it

seemed when it poised and stood perfectly still on its tight-rope, as

no Blondin could ever do. As stably poised it stood there as if it had

two rails beneath it instead of a single wire; and there was nothing

about it to suggest an explanation of the miracle, except that there

came from within the car the murmur of whirling wheels.

The mysterious wheels in question would be found, if we could look

within the structure of the car, to be two in number, arranged quite

close together on each side of the centre of the car. They are two

small fly-wheels, in closed cases, revolving in opposite directions,

each propelled by an electric motor. These are the wonder-workers. They

constitute the two-lobed brain or, if you prefer, the double-chambered

heart of the strange organism. All the world has learned to call them

gyroscopes. The vehicle that they balance may conveniently be termed a

gyrocar--a name that has the sanction of the inventor himself.

Let it be understood once for all that a gyroscope is merely a body

whirling about an axis. A top such as every child plays with is a

gyroscope; a hoop such as every child rolls is a gyroscope; the

wheels of bicycles, carriages, or railway-cars are gyroscopes; and

the earth itself, whirling about its axis, is a gyroscope. You can

make a gyroscope of your own body if you choose to whirl about, like

a ballet-dancer. In a word, the gyroscope is the most common thing

imaginable. Indeed, if I wished to startle the reader with a seeming

paradox, I might say without transcending the bounds of truth that,

in the last analysis, there is probably nothing known to us in the

universe but an infinitude of gyroscopes--atoms and molecules at one

end of the scale; planets and suns at the other--all are whirling

bodies. Still there are gyroscopes and gyroscopes, as we shall see.

GYROSCOPIC ACTION EXPLAINED

Now a word about gyroscopic action. If you have rolled a hoop or spun a

top you have unwittingly learned some practical lessons on the subject

which, had you possessed Mr. Brennan's imagination and ingenuity, might

have enabled you to anticipate him in the invention of the gyrocar.

Harking back to the days when you rolled hoops, you will recall that

the child who most excelled in the art was the one that could make the

hoop go fastest. The hoop itself might be merely a wheel of wire, which

would fall over instantly if not in motion; but if given a push it

assumed an upright position and maintained it with security, so long as

it was impelled forward. It seemed able, so long as it whirled about,

to defy the ordinary laws of gravity. A bicycle in motion gives an even

more striking illustration of the same phenomenon. And best of all, a

spinning-top. Everyone knows how this familiar toy, which topples over

instantly when at rest and can in no wise be balanced on its point,

rises up triumphant when whirled about, and stands erect, poised in a

way that would seem simply miraculous to all of us, had we not all

spun tops at an age when the world was so full of wonders that we

failed to marvel at any of them.

All these familiar things illustrate one of the principles of

gyroscopic action which Mr. Brennan has put to account in developing

his wonderful car--the fact, namely, that every revolving body tends

to maintain its chief axis in a fixed direction, and resents--if I

may be permitted to use this expressive word--having that direction

changed. The same principle is illustrated on a stupendous scale by our

revolving earth, which maintains the same tilt year after year as it

whirls on its great journey, notwithstanding the fact that the sun and

the moon are tugging constantly at its protuberant equatorial region in

a way that would quickly change its direction if it were not spinning.

But note, please, that whereas the whirling body assumes a certain

rigidity in space as regards the direction in which its axle points,

the mere translation of the body itself through space in any direction

is not interfered with in the least, provided the axle is kept parallel

with its original position.

You may test this if you like in a very simple way. Remove one of the

wheels of your bicycle, and carry it about the room, holding it by the

axle while it is spinning rapidly. You will discover that it requires

no more force to carry it when spinning than when at rest, provided you

do not attempt to tip it from its plane of rotation, but that if you do

attempt so to tip it, the wheel seems positively to resist, exerting

a force of which it did not show a trace when at rest. A large top,

arranged within the kind of frames or hoops called gimbals, if you can

secure such a one, will show you the same phenomenon; it will resist

having its axis diverted from the direction it chanced to have when it

was set spinning.

If you ask why the spinning wheel exerts this power, it may not be

easy to give an answer. The simplest things are hardest to explain.

No man knows why and how gravitation acts; no one knows why a body at

rest tends always to remain at rest until some force is applied to

it; nor why when a body is once in motion it tends always to move on

at the same rate of speed until some counter-force stops it. Such are

the observed facts; they are facts that underlie all the principles of

mechanics; but they are matters of observation, not of explanation or

argument. And the fact that a revolving body tends to maintain its axis

in a fixed position is a fact of the same category.

So far as we can explain it at all, we may, perhaps, say that the

inertia which the matter composing the wheel shares with all other

matter is accentuated by the fact that its whirling particles all tend

at successive instants to fly in different directions under stress

of centrifugal force. At any given instant each individual particle

tending to fly off in a particular direction may be likened to a man

pulling at a rope in that direction.

If you imagine an infinite number of men circled about a pole to which

ropes are attached, and evenly distributed, each one pulling with

equal force, it will be clear that the joint effort of the multitude

would result in fixing the pole rigidly at the centre. The harder the

multitude pulled, so long as they remained evenly distributed about

the circle, the more rigid the pole would become. But if, on the

other hand, all the men were to stop pulling and slacken the ropes,

the pole would at once fall over. The pole, under such circumstances,

would represent the axis of the revolving wheel, which acquired

increased stability in exact proportion to the increased velocity of

its revolutions, and therefore of the increased force with which its

particles tend to fly off into space.

But be the explanation what it may, the fact that the axis of a

revolving wheel acquires stability and tends to maintain its fixed

position in space is indisputable; and it is this fact which determines

primarily the action of the little revolving wheels of the gyroscopes

that balance Mr. Brennan's car. There are certain very important

additional principles involved that I shall refer to in a moment, but

first let us glance at the car itself and see how the gyroscopes are

arranged. We shall find them fastened within the frame-work of the car,

at its longitudinal centre, in such a way that their axles are parallel

to the axles of the ordinary car-wheels when the car stands in a normal

position. Granted that the gyroscopes are thus transverse and normally

horizontal, and at right angles to the track, the exact location of the

mechanism within the car is immaterial. But the two gyroscopes must

revolve in opposite directions for a reason to be given presently.

[Illustration: RETROSPECT AND PROSPECT IN TRANSPORTATION--THE DE WITT

CLINTON TRAIN AND THE GYRO-CAR.

The De Witt Clinton engine, with its archaic coaches, represents the

earliest type of railway transportation in America. The Gyro-car, two

views of which are given, is the working model of a single-rail vehicle

exhibited in England by Mr. Louis Brennan in 1907. It is balanced by an

ingenious gyroscopic mechanism, which its inventor believes will prove

equally successful when applied to vehicles on a commercial scale.]

MR. BRENNAN'S MODEL CAR

The Brennan car as at first exhibited was only a working-model about

six feet in length, and the gyroscopes that balanced it were about

five inches in diameter. It seems almost incredible that wheels so

small should be able to balance a car six feet in length, but it must

be understood that these small gyroscopes whirl at the rate of about

seven thousand revolutions per minute, and, of course, the gyroscopic

force is proportionate to the rate of revolution. If we recall that a

light hoop making perhaps fifty or a hundred revolutions per minute

acquires a considerable stability, we shall cease to wonder at the

rigidity of the axles of the wheels revolving at such enormous speed.

The model car accomplished the feat of carrying a passenger weighing

about one hundred and forty pounds across a little valley on a wire

cable, a voyage in some respects the most remarkable that any man has

thus far been privileged to make. The car has shown that it can go up

or down a sharp incline; but this, as a moment's reflection will show,

does not involve any change of direction of the gyroscopic axle, and

therefore involves only the ordinary laws of mechanics. It is all one

to the gyroscope whether the car moves on the level or up or down hill,

so long as it moves straight ahead.

Nor do the gyroscopes interfere in the least with the turning of the

car in passing round a curve, when the two of them are linked together,

as Mr. Brennan links them, so that any lateral change in the axis of

one is balanced by an opposite change of the axis of the other. With

the single gyroscope, such as Mr. Brennan used when he first began his

experiments, the car encounters difficulties at curves in the track.

But before we can understand how the two gyroscopes balance each other

in such a way as to make the Brennan car lean in while passing about

a curve, we must investigate more fully the action of the individual

gyroscopes. I have already said that there is another principle

involved as supplementary to the principle of the fixed axis; this we

must now investigate.

Perhaps it would be fairer to say that what we have to consider is

not a new principle but a complication as to the application of the

principle of gyroscopic action already put forward. In any event there

is an elementary fact about the gyroscope that I have not yet stated.

It is this: in order that the gyroscope may exercise its fundamental

property of holding its axis fixed, it must have that axis so adjusted

that it is free to oscillate or wabble. That sounds distinctly

paradoxical, but it is a very essential fact. If Mr. Brennan had merely

fixed two wheels rigidly in the frame of his car, they would have had

no appreciable effect in balancing it. Had nothing more than that been

necessary, some one would have invented a gyrocar long ago. But very

much more than that was necessary, as we shall see.

The complication of which I am speaking is illustrated by the action

of the simplest top, which likewise owes its stability to its wabble.

Your top does not rise merely because it spins, but because it wabbles

as it spins--wabbling being the familiar word for what the machinist

calls "precession." A freely spinning top, if in equilibrium, has no

inherency to rise up against gravitation, as your top may have led

you to suppose. Your top rises because it is not spinning freely in

equilibrium, its action being interfered with by the friction of the

point on which it rests; it is seeking a position of equilibrium,

which, owing to the location of its centre of gravity, will be found

when its spindle is erect. But a top supported at both ends and

properly balanced, does not tend to rise but only to maintain its

position.

HOW THE BRENNAN GYROSCOPES WORK

It is such a balanced top as this that we must call to our aid in

explaining the action of Mr. Brennan's gyroscopes. The explanation will

involve the use of a diagram perhaps rather unpleasantly suggestive of

the days when you studied geometry, and I fear I cannot hope to make

interesting reading of the explanation. But it will be worth your while

to follow it, that you may understand the action of one of the most

remarkable and ingenious of inventions. Figure 1 represents a kind of

top called a Foucault gyrostat. It is merely a top or gyroscope in

gimbal frames, such as I have already referred to. With certain slight

modifications, the diagram that represents it might also be a diagram

of one of the gyroscopes in Mr. Brennan's car. Indeed, it was such a

top as this that led Mr. Brennan to his discovery. Once while on a

visit to Cannes, he purchased a top like this of a street vender--and

the gyrocar is the outcome of the studies he made with it. This is also

the kind of top with which Foucault, after whom it is named, proved

that the earth revolves; but we shall come to that story in another

connection.

[Illustration: FIG. 1.]

Reverting to the diagram, the gyroscope or top proper is at the centre,

revolving on the axis _O A_. It is pivoted on the frame _B A C_,

which frame is in turn pivoted so that it can rotate on the axis _B

C_. Lastly, the outer frame _B D C E_ is pivoted on the axis _D E_.

Thus the apparatus as a whole is capable of revolving on each of its

three principal axes. But under ordinary conditions it is only the

inner wheel that is spinning. As this wheel is perfectly balanced, it

will maintain steadily any position that it chances to have when it

is set spinning, and the outer frames will remain stationary unless a

disturbing force is applied to them.

Suppose, now, that the wheel has been set spinning on its axis _O A_ in

the direction indicated by the arrow, while its axis is horizontal, as

represented in the diagram. The wheel will then tend to maintain its

position and resist any attempt to displace it. But its resistance will

be shown in a very peculiar way--whereby hangs our tale. If you apply a

steady downward pressure to the frame _B A C_ at point _A_, attempting

thus to deflect the axis of the spinning wheel of the gyroscope, the

frame will not tip down as you expect it to do (and as it would do if

the top were not spinning) but instead, it will move in a horizontal

plane along the arc _C A B_, the entire mechanism rotating on the axis

_D E_. This motion is equivalent to the wabble of the top, and it is

called "precession."

Please remember the word and its meaning, for we must use it repeatedly.

But now, curiously enough, if you were to apply a sidewise pressure at

_A_, pushing to the left (as we view the diagram) to help on the motion

of precession, the obstinate apparatus will cease altogether to move in

that direction and the point _A_ will begin to rise instead, the frame

_B A C_ rotating on its axis _B C_. This rise of the axis _O A_ will

take place even though the downward pressure is continued. You have

disturbed the equilibrium of the top--unbalanced it--and it must seek a

new position. Contrariwise, if you would have the point A moved to the

right, you must push it upward; if you would have it go down, you must

push it to the right.

This seems rather weird behavior, but if you will note the direction

of the arrow on the wheel you will see a certain method in it. It will

appear that in each case the force you apply has been carried round

a corner, as it were, by the whirling disc, and made to act at right

angles to the direction of its application. This change of direction

of a force applied is strictly comparable to the change effected by

the familiar device known as a pulley. With that device, to be sure,

a pull instead of a push is used, but this is a distinction without a

difference, for pushing and pulling are only opposite views of the same

thing.

Possibly this suggested explanation of the action of the gyrostat may

not seem very satisfactory, but the facts are perfectly clear, and

if you will bear them steadily in mind you will readily be able to

understand the Brennan gyroscope, as you otherwise cannot possibly

hope to do. You have only to recall that pushing down at _A_ causes

motion (called "precession") to the left, and pushing up at _A_, motion

to the right; and that in order to make _A_ either rise or fall, you

must "accelerate precession" by pushing to the left or to the right,

respectively. But you must understand further, that when, through the

application of any of these disturbing forces, you have forced the axis

_O A_ into a new position, it will tend to maintain that new position,

having no propensity whatever to return to its original position. It is

quite as stably in equilibrium with its axis pointing upward as when in

the position shown in the diagram. One position is quite like another

to it; but having accepted a position it resents any change whatsoever.

Now we are prepared to understand the Brennan gyroscope, which consists

essentially of two such gyrostats as that shown in our diagram _A_, set

into the frame of the car on the axis _D E_, their wheels revolving

in opposite directions and their outer frames so linked together that

when one turns in one direction on its axis _D E_, the other must turn

in the opposite direction. As the sole object of having two of the

gyroscopes is to facilitate the going around curves, we may for the

moment neglect the second one, and consider the action of only one of

the pair.

Our diagram 2, then, will represent one of Mr. Brennan's gyroscopes

in action. It is pivoted into the framework of the car on the axis _D

E_. If you examine it you will see that it is essentially the Foucault

gyrostat of our other diagram, with the axis _O A_ projected beyond the

frame to the point _F_.

In practice, the frame _B A C_ is made to carry the field-magnet of

an electric motor for spinning the wheel. But this in no wise affects

the principles of action. Mr. Brennan's invention consists of the

exceedingly ingenious way in which he applies these principles; and

to understand this we must follow our diagram closely. Looking at it,

you will see that the spindle _O F_ carries two rollers _R1_ and _R2_

which may come in contact under certain circumstances with the curved

segment marked _G1_, _G2_, _G3_, _G4_, which are strong segments of

the car-frame itself--the segments, indeed, upon which the force

of the gyroscope is expended in holding the car in equilibrium. It

must be understood further that the roller _R1_ is loosely fitted to

the spindle _O F_ and hence can whirl with it when pressed against

the segment _G1_ or _G3_; whereas the roller _R2_ is fitted about a

non-revolving extension of the frame _B A C_, and not to the spindle

itself. Bearing in mind that the gyroscope itself is perfectly balanced

and hence tends to maintain its axis _O F_ in a fixed direction, we

shall be able to understand what must happen when the car is tipped

from any cause whatever--as the shifting of its load, the pressure of

the wind, or the centrifugal action due to rounding a curve.

[Illustration: FIG. 2.]

Suppose, for example, that the car tips to the right. This will bring

the segment _G1_ in contact with the roller _R1_, and the roller will

instantly tend to run along it, as a car-wheel runs along the track,

because friction with the spindle causes it to revolve. But this, it

will be evident, is equivalent to pushing the spindle _F_ (or the frame

_A_) toward _B_--"accelerating the precession"--and we know that the

effect of such a push will be to cause the spindle (thanks to that

round-the-corner action) to rise, thus pushing up the segment _G1_, and

with it the car itself.

The thrust will cause the car to topple to the left and this will free

the roller _R2_, but a moment later it will bring the segment _G2_ in

contact with roller _R2_ which thus receives an upward thrust. But an

upward thrust, we recall, will not cause the spindle to move upward,

but off to the right toward _C_; and so, a moment later still the

roller _R2_ will pass beyond the end of the segment _G2_ and the roller

_R1_ will come in contact with the segment _G3_, along which it will

tend to roll, thus accelerating the precession to the right, and so

causing the spindle to push downward, bringing the car back to its old

position or beyond it; whereupon the segment _G4_ will be brought in

contact with _R2_, retarding the further oscillation of the car and

causing the spindle to move back again to the left.

This sequence of oscillations will be repeated over and over so long

as any disturbing force tends to throw the car out of equilibrium. In

other words, the gyroscope, when its balance is disturbed by a thrust

due to any unbalancing of the car, will begin to wabble and continue

to wabble until it finds a position where it is no longer disturbed,

and this new position will be attained only when the car as a whole is

perfectly balanced again.

In this new position of balance, the car (owing to a shift of its load

or to the force of the wind) may be tipped far over to one side, as

a man leans in carrying a weight on one shoulder, to get the centre

of gravity over the rail, and in that event the axis of the gyroscope

will be no longer horizontal. But that is quite immaterial. There is

no more merit in the horizontal position than in any other, as regards

the tendency to keep a fixed axis. If it is usually horizontal, this is

only because under normal conditions the car will be balanced at its

physical centre, just as ordinarily a man stands erect and does not

lean to one side in walking.

Reverting for a moment to our diagram and the explanation just given,

it will be understood that the two rollers R1 and R2 are never in

action at the same time, and that it is only the roller R1 that gives

the sidewise push that accelerates the precession (since R2 is not in

contact with the axle itself).

The function of R2 is to retard the precession and bring the axis

to its normal position at right angles to the rail on which the car

runs. There is nothing of mystery about the action of either which the

action of our gyrostat does not explain, but the mechanism by which the

different segments of the car are made to push against the spindle, and

so force it to balance the car in order that it may maintain its own

balance, is exceedingly ingenious. Mr. Brennan himself tells me that he

has improved methods of accomplishing these results, which are not yet

to be made public. The principle, however, is the same as that outlined

in the earlier patents which I have just described.

If you have taken the trouble to follow carefully the description just

given, you will be prepared to understand the anomalies of action of

the gyrocar; for example, why its side rises when a weight is placed

on it; why it leans toward the wind, and why it leans to the inner and

not to the outer side of the track in rounding a curve. The substance

of the explanation is that the greater the force brought to bear on

the roller R1 by the segment of the car that strikes against it, the

stronger its precession, and hence the more powerful its lift. The

oscillations and counter-oscillations thus brought about continue to

operate powerfully on the roller R1 so long as the weight of the car is

out of balance; and balance is restored only when the heavier side of

the car rises, bringing the centre of gravity over the track, just as a

man carrying a weight on the right shoulder leans toward the left, and

vice-versa. Thus, when the gyrocar has a heavy weight on one side, or

encounters a strong wind, it may lean far over, but still be perfectly

and securely balanced, the gyroscopes finally remaining quiescent in

their new position until some new disturbance is applied.

It remains to be said, however, that there is another element

introduced when the car rounds a curve. To understand this, we must

revert to the action of the Foucault gyrostat, as illustrated in

diagram 1. If you held such a gyrostat in your hand in the upright

position in which it is shown in the diagram, and whirled it about, the

axis _O A_ would of course maintain a fixed direction so long as the

gyrostat was free to revolve on the axis _D E_. But if you prevented

such revolution, as by clutching the spindle _E_ firmly, and then

whirled the gyrostat about at arm's length, the axis _O A_ would at

once be forced to take an upright position. If your hand whirled to

the right, the point _A_ would rise; if your hand whirled to the left,

the point _A_ would go down; the principle determining this motion in

either case being that the direction of whirl of the gyroscope must

correspond to the direction of curve given to the apparatus as a whole

by the motion of your arm.

Exactly the same principle applies to the Brennan gyroscope when the

car to which it is attached goes about a curve. The frame pivoted at

_D E_ revolves only within a limited arc, and then becomes fixed, and

so the axis _O F_ tends to tip upward when the car rounds a curve. If

only a single gyroscope were used, this would tend to make the car tip

in opposite directions, according to whether the car is going forward

or backward, and the tip might be dangerous in going about a curve, as

Mr. Brennan found to his cost in his earlier experiments. But when the

two gyroscopes, revolving in opposite directions, are linked together,

the action of one balances that of the other, and their joint effect is

always to make the car lean in at a curve, which is precisely what it

should do to ensure safety. Moreover, the two linked gyroscopes keep

their planes of revolution parallel to the rail, as is essential to

their proper action, and as a single gyroscope would not do.

The balancing action of the gyroscope seems no whit less remarkable

after it is explained. It should be said, however, that the force

exerted by the mechanism is not so tremendous as might at first

thought appear, for the gyroscopes are by no means called upon to

counteract the entire force of gravity brought to bear on the car.

They do not in any sense _lift_ the car; they only balance its two

sides, which when left to themselves are approximately of equal

weight. The car, as a whole, weighs down on the track just as heavily

with the gyroscopes in action as when they are still. Balancing is a

very different feat from lifting, as everyone is aware from personal

experience. Two men pushing against the opposite sides of a monorail

car could keep it balanced on the central rail though its weight vastly

exceeded anything they could lift.

THE EVOLUTION OF AN IDEA

It goes without saying that so elaborate a mechanism as Mr. Brennan's

gyroscope was not perfected in a day. Neither was it hit upon by

accident. It belongs in the category of inventions that were thought

out to meet a mechanical need. Mr. Brennan is an Irishman by birth,

but he was taken by his parents to Australia at the age of nine and

remained there throughout the years of his early manhood. Observation

of the condition of the roads in Australia, and of the enormous

retardation of development due to inadequate transportation facilities

led him to ponder over the possibilities of improvement in this

direction, as he was jolted about the country in a coach with leather

straps in lieu of springs. It became clear to him that a way must be

found to build railroads more cheaply. Furthermore, it was brought to

his attention through observation of the condition of the cattle that

were shipped from North Australia across the continent, that a railway

car that would enable the cattle to make the journey in comfort, and

thus arrive in marketable condition, would have enormous value for this

purpose alone.

For years, Mr. Brennan tells me, the problem haunted him, of how

to make a monorail car balance itself. He studied the action of

rope-walkers, and he attempted various crude methods of balancing a

car, which all came to nothing. He thought about the possibility of

using the gyroscope, and even purchased several elaborate gyrostats in

order to study gyroscopic action. As a friend of Sir Henry Bessemer, he

knew of that gentleman's experiments with the gyroscope in attempting

to make a steady room in a ship, but these also availed him nothing. It

was not until he purchased the toy top at Cannes, as already mentioned,

that he got hold of a really viable idea; and then, of course, almost

numberless experiments were necessary before an apparatus was devised

that could meet all the requirements.

At last, however, a model car, more than fulfilling all his fondest

hopes, was in actual operation. It remained to build a car of

commercial size. To aid him in thus completing his experiments,

Mr. Brennan received a grant of $30,000 from the India Society. He

believed that a car one hundred feet long and sixteen feet wide would

be balanced by gyroscopes three and a half feet in diameter, so

effectively that it would stand erect and rigid though fifty passengers

were clustered on one side of its spacious room.

The accuracy of this prediction was put to the test in November, 1909,

when Mr. Brennan exhibited the first gyrocar of commercial size. The

result was demonstrative and convincing. The large car, carrying forty

or fifty passengers, operated exactly as its inventor had foretold,

and the doubts of the most skeptical were set at rest. Photographs of

the car in actual operation, with its load of passengers, were sent

broadcast, and it became apparent that the introduction of the gyrocar

in competition with railway, trolley, and motor cars of the old type

would be only a matter of time.

When we come thus to consider the gyrocar as a vehicle in which all

of us may soon have an opportunity to ride, there is one practical

question that is sure to present itself to the mind of almost every

reader. What will be the effect should the electrical power that drives

the gyroscopes give out at a critical moment, as, for instance, when

the car is just crossing a gorge or river on a cable? Mr. Brennan's

ingenuity has anticipated this emergency. The gyroscopes that balance

his cars operate in a vacuum, and all the bearings are so well devised

as to give very little friction. The wheels will continue running for

a considerable time after the power is shut off. The large gyroscopes

of the commercial car, it is estimated, will perhaps require two hours

to attain the highest rate of rotation, but they will then continue

revolving at an effective speed for some hours, even if no further

power is applied to them.

It may be said, too, that the gyrocar is provided with lateral legs

that may be let down in case of emergency or when the car is not in

use, to avoid waste of energy in needless running of the gyroscope.

All in all, it would appear that the dangers of travel in a gyrocar

should be fewer than those that attend an ordinary double-track car;

and Mr. Brennan believes that it will be possible, with the aid of the

new mechanism, to attain a speed of one hundred and fifty, perhaps even

two hundred miles an hour with safety.

[Illustration: TWO VIEWS OF MR. LOUIS BRENNAN'S MONO-RAIL GYRO-CAR.

The gyroscopic mechanism for automatically balancing the car is

contained in the cab-like anterior portion. The platform of the car

maintains its equilibrium even when the forty passengers are crowded on

one side, as shown in the upper picture.]

VIII

THE GYROSCOPE AND OCEAN TRAVEL

It must not be supposed that Mr. Louis Brennan's remarkable monorail

car affords the first illustration of an attempt to make practical use

of the principles of gyroscopic action. The fact is quite otherwise.

The idea of giving steadiness to such instruments as telescopes and

compasses on shipboard with the aid of gyroscopes originated half a

century ago, and was put into fairly successful operation by Professor

Piazzi Smyth (in 1856). More than a century earlier than that (in

1744), an effort was made to aid the navigator, by the use of a

spinning-top with a polished upper surface, to give an artificial

horizon at sea, that observations might be made when the actual horizon

was hidden by clouds or fog. The inventor himself, Serson by name,

was sent out by the British Admiralty to test the apparatus, and was

lost in the wreck of the ship _Victory_. His top seemed not to have

commended itself to his compatriots, but it has been in use more or

less ever since, particularly among French navigators.

BESSEMER'S COSTLY EXPERIMENT

These first attempts to use the gyroscope at sea were of a technical

character, and could have no great popular interest. But about

twenty-five years ago an attempt was made to utilize the principle of

the spinning-top in a way that would directly concern the personal

comfort of a large number of voyagers. It was nothing less than the

effort to give stability to a room on a steamship, in order that the

fortunate occupant might avoid the evils of seasickness. The man who

stood sponsor for the idea, and who expended sums variously estimated

at from fifty thousand to more than a million dollars in the futile

attempt to carry it into execution, was the famous Sir Henry Bessemer,

famed for his revolutionary innovations in the steel industry. It would

appear that Bessemer's first intention was to make a movable room to be

balanced by mechanisms worked by hand. But after his project was under

way his attention was called to the possibility of utilizing gyroscopic

forces to the same end. As the story goes, he chanced to purchase a top

for sixpence, and that small beginning led him ultimately to expend

more than a million dollars in playing with larger tops. His expensive

toy passed into history as the "Bessemer chamber." It was actually

constructed on a Channel steamer; but the would-be inventor, practical

engineer though he was, did not find a way properly to apply the

principle, and his experiment ended in utter failure.

With this, the idea that the gyroscope-wheel could ever aid in

steadying a ship at sea seemed to be proved a mere vagary unworthy the

attention of engineers. But not all experimenters were disheartened,

and since the day of Sir Henry Bessemer's fiasco a number of workers

have given thought to the problem--with the object, however, of

applying the powers of the revolving wheel not merely to a single

room but to an entire ship. I have personal knowledge of at least one

inventor, quite unknown to fame, who believed that he had solved the

problem, but who died before he could put his invention to a practical

test. It remained for a German engineer, Dr. Otto Schlick, to put

before the world, first as a theory and then as a demonstration, the

practical utility of the revolving wheel in preventing a ship from

rolling.

DR. SCHLICK'S SUCCESSFUL EXPERIMENT

In the year 1904 Dr. Schlick elaborated his theory before the Society

of Naval Architects in London. His paper aroused much interest in

technical circles, but most of his hearers believed that it represented

a theory that would never be made a tangible reality. Fortunately,

however, Dr. Schlick was enabled to make a practical test, by

constructing a wheel and installing it on a small ship--a torpedo-boat

called the _Sea-bar_, discarded from the German navy. The vessel is one

hundred and sixteen feet in length and of a little over fifty-six tons'

displacement. The device employed consists of a fly-wheel one meter in

diameter, weighing just over eleven hundred pounds and operated by a

turbine mechanism capable of giving it a maximum velocity of sixteen

hundred revolutions per minute. This powerful fly-wheel was installed

in the hull of the _Sea-bar_ on a vertical axis, whereas the Brennan

gyroscope operates on a horizontal axis. So installed, the Schlick

gyroscope does not interfere in the least with the steering or with

the ordinary progression of the ship. Its sole design is to prevent the

ship from rolling.

The expectations of its inventor were fully realized. On a certain day

in July, 1906, with a sea so rough that the ship rolled through an

arc of thirty degrees, when the balance-wheel was not in revolution,

the arc of rolling was reduced to one degree when the great top was

set spinning and its secondary bearings released. In other words, it

practically abolished the rolling motion of the craft, causing its

decks to remain substantially level, while the ship as a whole heaved

up and down with the waves. These remarkable results, with more in

kind, were recorded in the paper which Sir William White read before

the Institution of Naval Architects in London in April, 1907. He

himself had witnessed tests of the Schlick gyroscope, and, in common

with his colleagues, he accepted the demonstrations as unequivocal.

Fully to understand the action of Dr. Schlick's invention, one must

know that it is not a mere wheel on the single pivot, but a wheel

adjusted in such a fashion that it can oscillate longitudinally while

revolving on its vertical axis. In other words, it is precisely as

if one of the two gyroscope-wheels used in the Brennan car (greatly

enlarged) were so placed that its main axis was vertical, its secondary

axis, or axis of oscillation, being horizontal and at right angles to

the ship's length. Thus, while spinning on its vertical axis the body

of the top is able to oscillate, pendulum-like, lengthwise of the ship.

In principle the action of this wheel is not different from that of an

ordinary top on your table which wabbles to the right or to the left

when you push its axis straight away from you. Yet to the untechnical

observer it seems as if the Schlick gyroscope were a living thing,

governed by almost human motives. If you apply a brake to prevent the

longitudinal oscillations of the gyroscope, the effect, even though the

fly-wheel still revolves at full speed, is precisely as if you pinioned

the arms of a strong man, so that he saw the futility of resistance

and made no struggle to free himself. Under such circumstances the

gyroscope--though it continues to spin as hard as ever--has no effect

whatever in preventing the rolling of the ship; it stands there, like

the strong man bound, expressing its discontent with an angry groan.

But if you release the brake so that the entire mechanism is free to

oscillate lengthwise of the ship, all is changed. It is as if you cut

the cords that bound the strong man's arms. Instantly the mechanism

springs into action. It will no longer allow itself to be swung with

each roll of the ship; it will resist and prove which is master. Its

mighty mass, pivoted on the lateral trunnions, lunges forward and

backward with terrific force, as if it would tear loose from its

bearings and dash the entire ship into pieces. It causes the ship to

pitch a trifle fore and aft as it does so; but meantime its axis stands

rigidly erect in the lateral plane, though the waves push against the

sides of the ship as before. The decks of the vessel, that were tipping

from side to side, so that loose objects slid from one rail to the

other, are now held rigidly at a level, scarcely permitted to deviate

to the extent of a violent tremor. The gyroscope has won the contest.

To maintain its victory it must continue its backward and forward

plunging; but from side to side its axis will not swerve.

DID GYROSCOPIC ACTION WRECK THE _VIPER_?

It was the failure to understand that a gyroscope-wheel, to work

effectively, must be given opportunity to oscillate in this secondary

fashion that led Sir Henry Bessemer to spend an enormous sum in a vain

effort to accomplish on a small scale what Dr. Schlick's gyroscope

accomplishes for the entire ship. Now it is clearly understood that

a marine gyroscope on an absolutely fixed shaft cannot exercise its

full action; but there is still a good deal of difference of opinion

among engineers as to just how much a spinning body must be permitted

to oscillate in order to make its gyroscopic effects noticeable. The

discussion that has taken place over the loss of the torpedo-boat

_Viper_ furnishes a case in point.

Some critics contend that the loss of the boat was due to the

gyroscopic action of its turbine engines. They believed that the

turbine at the stern of the little ship held that portion of the craft

in a rigid plane, while the anterior portion of the ship, caught in the

trough of a wave, broke away. That the ship broke in two is certain;

but competent engineers have denied that gyroscopic turbines could have

had any share in its destruction. According to their view, the turbines

of a ship are powerless to exert the gyroscopic action in question,

because their axes are fixed and they thus have not the opportunity for

secondary oscillation to which I have referred. Meanwhile there are

other equally competent mechanicians who believe that the vibration

or oscillation of the body of the ship itself may suffice, under

certain circumstances, to give the turbine precisely such freedom of

motion as will enable it to exercise a powerful gyroscopic effect.

Dr. Schlick himself contends, and seems with the aid of models to

demonstrate, that such a gyroscopic action is exercised by the wheels

of a side-wheel steamer, which revolve on a shaft no less fixed than

that of a turbine. If such is the case, there would seem to be no

reason why a turbine-engine may not at times exercise the power of a

tremendous gyroscope, such as it obviously constitutes. The question

must find practical solution at the hands of the naval architects of

the immediate future, as turbine engines are now in use in several of

the largest steamships afloat, and others are being installed in craft

of all descriptions.

THEORETICAL DANGERS OF THE GYROSCOPE

It should be said that engineers disagree as to the practical utility

of the Schlick gyroscope. No one questions that it steadies the ship,

but some critics think that its use may not be unattended with danger.

It has been suggested that under certain circumstances--for example,

the sudden disturbance of equilibrium due to a tremendous wave--the

gyroscope might increase the oscillation of the ship to a dangerous

extent, though ordinarily having the opposite effect.

The danger from this source is probably remote. There is, however,

another danger that cannot be overlooked, and which marine architects

must take into constant account. What we have already seen has made

it clear that the revolving wheel of the Schlick gyroscope, to be

effective, must bear an appreciable relation to the mass of the entire

ship. Such a weight, revolving at a terrific speed and oscillating

like a tremendous pendulum, obviously represents an enormous store

of energy. It was estimated by Professor Lambert that a gyroscope of

sufficient size to render even a Channel steamer stable would represent

energy equal to fifty thousand foot-pounds--making it comparable,

therefore, to an enormous projectile. Should such a gyroscope in action

break loose from its trunnions, it would go through the ship with all

the devastating effect of a monster cannon ball.

The possibility of such a catastrophe is perhaps the one thing that

will cause naval architects to go slowly in the adoption of the new

device. We can hardly suppose that the difficulties represented are

insuperable, but undoubtedly a long series of experiments will be

necessary before the Schlick gyroscope will come into general use.

The apparatus has been tested, however, on a German coast steamer. It

may not be very long before craft of the size of Channel steamers and

boats that go to Cuba and the Bermudas are equipped with the device.

Naturally enough, this prospect excites the liveliest popular interest.

Visions of pleasant ocean voyages come before the mind's eye of many a

voyager who hitherto has dreaded the sea.

But whatever the future of the gyroscope as applied to pleasure-craft,

there can be little doubt about its utility as applied to vessels of

war. It seems a safe enough prediction that all battle-ships will be

supplied with this mechanism in the not distant future. Amid the maze

of engines of destruction on war-vessels, one more will not appal

the builder; while the advantage of being able to fling a storm of

projectiles from a stable deck must be inestimable.

IX

NAVIGATING THE AIR

If it were possible to regard all medieval literature without more than

a grain of doubt, we must believe that aerial flight by human beings

was accomplished long before science had risen even to the dignity of

acquiring its name. Thus, it is recorded by a medieval historian that

during the reign of Charlemagne some mysterious persons having acquired

some knowledge of aerostatics from the astrologers, who were credited

with numerous supernatural powers, constructed a flying-machine, and

compelling a few peasants to enter it, sent them off on an aerial

voyage. Unfortunately for the unwilling voyagers, so the story runs,

they landed in the city of Lyons, where they were immediately seized

and condemned to death as sorcerers. But the wise bishop of the city,

doubting the story of their aerial journey, pardoned them and allowed

them to escape.

That such a fabulous tale could gain credence is explained by the

prevailing belief in the powers of the astrologers and sorcerers at

that time. People who could seriously believe that an alchemist could

create gold and prolong life and youth indefinitely, would find nothing

startling in the announcement that he could also perform the relatively

simple feat of flying--a thing that birds and bats accomplish with

such obvious facility. And nothing is more certain than that attempts

at aerial flight have been made at various times since the beginning of

history.

As with almost everything else in the matter of modern scientific

advancement, the mysterious writings of the monk, Roger Bacon, are

supposed to contain passages to show that the worthy friar had an

inkling of the secret of air navigation. But he himself admits that he

had only a theoretical knowledge of the subject, and had never seen a

flying-machine of any kind in actual flight.

Much more definite and tangible are the designs of possible

flying-machines still extant in the sketch-book of Leonardo da Vinci,

made in the fifteenth century. From Leonardo's sketches it appears that

the artist had conceived the idea of constructing jointed wings to be

worked with strings and pulleys, the motive power to be that of a man's

arms and legs. It appears also that later he had very definite ideas

as to the possibilities of an aerial screw, and he is believed to have

constructed one of these screws made on the same general plan as that

of the ordinary type of windmill in use at that time. But nothing of

practical importance came of any of Leonardo's experiments.

It is probable that his abandonment of the project of flying by means

of wings worked by muscular force was due to the discovery that the

strength of the muscles of even the strongest man was relatively slight

as compared with the corresponding muscle of birds. Leonardo was

peculiarly capable of discerning this discrepancy in strength, since

he himself was one of the strongest men of his time. It is said that

he could bend and straighten horseshoes with his hands. But in his

experiments with the aerial screw he probably discovered very soon that

even such muscular force as he was capable of exerting was entirely

inadequate; and there being no other mode of producing power at that

time, the idea of aerial navigation by this means was also abandoned.

About this time some imaginative persons, realizing the possibilities

of muscular development when begun in childhood and persistently

practiced, attempted the development of a race of men whose abnormally

strong pectoral muscles would enable them to use artificial wings for

flying. For this purpose a certain number of young boys were selected

and constantly drilled in exercises of flapping the arms, to which

broad sails were attached. These attempts were persisted in for several

years, and it is said that some of these boys became so expert that by

skipping along the surface of the ground and vigorously flapping their

wing-attachments, they could travel at incredible speed, although never

able actually to rise from the ground.

In 1678, a Frenchman named Besnier invented a flying-machine that is

credited with being more successful than any hitherto attempted. His

machine consisted of two bars of wood which were so hinged to a man's

shoulders that they could be worked up and down by movements of the

hands and feet. At the ends of these two bars were muslin wings made

like shutters, so arranged that they were opened by a downward stroke

and closed automatically by a reverse motion. The general appearance

presented by these wings was that of four book-covers fastened by

their backs to the ends of the bars, opening and closing alternately as

the bars were worked up and down.

The inventor began his experiments in a modest way. His first attempt

at flight was by jumping from a chair; next he tried a table; and

finally, emboldened by his success, he made flights from window-sills

and even house-tops. On one occasion he is said to have sailed from

his attic window over the roof of a neighboring cottage, alighting,

without injury, some distance beyond. It was even rumored at one time

that he would try to fly across the Seine, but if such a feat was ever

contemplated, it was never attempted.

Half a century later, however, the Marquis de Bacqueville actually made

such an attempt with a machine somewhat similar to that of Besnier. The

marquis had practiced in private with his machine with such encouraging

results that he felt confident the feat was not an impossible one--in

fact, that he was sure of accomplishing it. He therefore announced

publicly that at a certain time the attempt would be made, and on the

appointed day an immense crowd of people gathered on the banks of the

river to witness the spectacle. Starting from a building some little

distance away from the stream, the marquis made good progress at first,

but just as he reached the river-bank his machine collapsed and he was

tumbled out, alighting on a barge moored at the edge of the stream.

Fortunately, the only injury he sustained was a broken leg; but this

single attempt seems to have satisfied his aeronautic ambitions.

Until this time all attempts made at aerial flight had been those in

imitation of birds; but during the early part of the eighteenth century

the idea of the balloon was developed. This was the result of the

numerous important discoveries made about that time as to the qualities

of the atmosphere, and also several other "airs," as gases were called,

such as their expansion and contraction under different conditions of

temperature.

In 1766 the English philosopher, Henry Cavendish, discovered that

hydrogen gas has only about one-seventh the weight of an equal bulk

of air, this scientific discovery pointing naturally to balloon

construction, since obviously if such a light gas were confined in a

suitable receptacle, the device would rise to a certain height through

the heavier atmosphere, as a cork rises through water. At the same

time the experiments of the chemist, Dr. Joseph Black, and those of

his younger contemporary, Doctor Priestly, were directed along the

same lines, all of them pointing to the possibility of constructing an

aerostat with buoyancy and lifting-power, and Priestly's _Experiments

Relating to the Different Kinds of Air_ is said to have been directly

responsible for stimulating the efforts of Stephen and Joseph

Montgolfier, the French paper manufacturers, who finally invented and

sent up the first balloon.

Even before Montgolfier's invention, Tiberius Cavallo, an Italian

living in England, had demonstrated the possibility of making

toy-balloons. But the balloons of Cavallo were small affairs made

of bladders or paper bags filled with hydrogen gas. One of these

materials being too heavy and the other too porous for successful

balloon construction, the performances of these toy-balloons were not

conclusively demonstrative.

THE BALLOON INVENTED

Throughout the entire spring of 1783, all Auvergne, in France, was kept

in breathless expectancy by constant rumors that the two Montgolfiers

had really solved the problem of aerial flight, and would soon be seen

soaring over the country in a strange birdlike machine. Rumor pictured

this machine in various forms and sizes, but in point of fact there was

really very little secrecy on the part of the inventors themselves, who

frankly explained the principle of the balloon they were constructing.

It was hardly to be expected, however, that most persons would believe

the plain truth that so simple a device as a bag filled with hot air

would do what had long been considered impossible.

Spring advanced and lapsed into summer, however, and as no

flying-machine made its appearance, public clamor became so loud that

the Montgolfiers felt they could postpone their demonstration no

longer, although the balloon they were working on was not completed to

their entire satisfaction. Nevertheless, they fixed on the definite

date of June 5, (1783) as the day and Annonay as the place for making

the trial, and their faith in their invention was shown by the fact

that special invitations were sent to the leading persons in the

vicinity, and a general invitation extended to the world at large.

But in place of some complicated and birdlike machine, as rumor had

pictured the flying-machine, the multitude that gathered about the

starting-point found only an immense cloth bag about thirty-five feet

in diameter, without machinery or wings, and capable of containing some

twenty-two thousand cubic feet of air, which the Montgolfier brothers

and their assistants were inflating with heated air. As the bag filled,

one of the brothers announced with all seriousness, that as soon as it

was completely filled it would "rise to the clouds," carrying with it a

frame weighing some three hundred pounds.

This announcement was not received with the same seriousness with

which it was given. The idea of expecting anyone to believe that an

ordinary cloth bag would fly excited the risibilities even of the

more serious members of the crowd. Nevertheless, as the great globe

filled it became evident to the spectators that it was tugging at the

restraining ropes in efforts to rise, in a most extraordinary manner;

and when, at a signal from the inventors, the ropes were cast off and

the monster shot skyward, the crowd's smiles were turned to expressions

of gaping astonishment. Straight into the air the monster mounted,

and then, wafted by a gentle breeze, it continued to soar and rise

until in ten minutes it had reached an altitude of six thousand feet,

sailing easily in a horizontal direction for a short distance, then

gradually descending and alighting some eight thousand feet from the

starting-point.

The news of this triumph travelled quickly to Paris, and the Parisians

clamored to see the wonderful performance repeated in the capital. The

king and court were as interested as the savants and the populace, and

an order was sent at once by his Majesty, bidding the brothers bring

their balloon to the city.

In the meantime, however, a savant named Charles had started the

construction of a balloon that was to be filled with hydrogen gas

instead of heated air. This was a much more expensive undertaking, as

a thousand pounds of iron filings and five hundred pounds of sulphuric

acid were necessary to manufacture a sufficient quantity of gas to

fill the varnished silk bag. But by the 23rd of August everything

was in readiness for the filling process, and the following day this

first gas-balloon rose from the Champs de Mars to a distance of three

thousand feet and disappeared into the clouds. Three-quarters of an

hour later it descended in a field near the little village of Gonesse,

to the great consternation of the inhabitants of the neighborhood,

who supposed it to be some monster bird, animal, or flying dragon.

Arming themselves with scythes and pitchforks, therefore, but keeping

at a safe distance, the boldest of the peasants sallied out and

surrounded the field in which the creature had alighted. As it made no

offensive movement, however, one bold huntsman armed with his trusty

fowling-piece, crept cautiously within range and fired, tearing a

hole in the monster's side and causing it to writhe and collapse,

giving off what appeared to be a foul-smelling, poisonous gas in its

death-struggles. When finally it lay flat and still the villagers

became emboldened, and rushing upon it cut and tore it to shreds,

ending the performance by tying the fragments to a horse's tail and

sending the animal scurrying across the fields.

In anticipation of some such demonstration as this, the French

Government had sent out a proclamation on the day of the ascent.

"Anyone who should see in the sky a globe, resembling the moon in an

eclipse," the proclamation ran, "should be aware that far from being

an alarming phenomenon, it is only a machine, made of taffeta, or

light canvas covered with paper, that cannot possibly cause any harm,

and will some day prove serviceable to the wants of society." But

apparently none of the villagers of Gonesse had seen this proclamation.

The success of these balloon ascensions sent a wave of enthusiastic

interest in aeronautics all over France. The novelty and possibilities

of ballooning appealed to the French temperament, just as the

possibilities of submarine navigation and automobiling did a century

later. As a result, France became at once the centre of ballooning, the

whole nation being eagerly absorbed in the subject of navigating the

air. In the theatre of action, the Montgolfiers continued to occupy the

centre of the stage, and at all times showed themselves worthy of the

leading rôle. Pursuant to the order of the king, M. Montgolfier had

come to the capital, and on September 19th, before Louis XVI and his

queen and the court at Versailles, sent up another hot-air balloon, or

"Montgolfier," as this kind of balloon had come to be called.

A novel and important feature of this exhibition, however, was the

substitution of living animals for sand-bags or other ballast, as used

heretofore. In a wicker cage a cock, a duck, and a sheep were fastened,

and these were carried some fifteen hundred feet into the air,

descending uninjured, two miles from the starting-point, a few minutes

later. The cage was broken open in the descent, but its occupants

escaped injury, and the sheep was found quietly grazing when the rescue

party arrived.

The successful voyage of these caged animals stimulated the balloonists

to attempt the crucial test of sending up a balloon carrying a human

passenger. But from this perilous undertaking the boldest spirits

recoiled, even the Montgolfiers refusing to venture. In those days,

however, there was always a means of securing human beings, willing

or otherwise, for any undertaking. Where gold would not tempt, it

needed but a word of the monarch to commute the death-sentence of some

criminal, placing him at the disposal of the scientists for a better

or worse fate than the gallows, as the case might be. And so when

Louis XVI heard of the plight of the balloon-makers, he came to their

assistance with the offer of two condemned prisoners to be sent on the

first aerial voyage. This offer had an unexpected effect. The pride of

a certain high-minded aeronaut named Rozier, who had hitherto refused

to risk his life, was touched at the thought of criminals performing an

act that all honest men refused. "What! are vile criminals to have the

glory of being the first to ascend into the air?" he exclaimed. "No,

no, that must not be." And forthwith he offered his own services for

the hazardous undertaking.

The royal decree was accordingly repealed, to the chagrin of the

criminals, no doubt, and preparations made for the momentous attempt.

Montgolfier was engaged to construct a large balloon, and on the 15th

of October, 1783, the trial was made in a garden in the Faubourg St.

Antoine. Let no one suppose, however, that this first man-carrying

balloon was cut loose from the earth and sent skyward to shift for

itself, as might be gathered from the reluctance of persons to make the

ascent. On the contrary, the balloon was held by strong cables, and

allowed to rise only to a height of eighty feet--to the level of some

of the lower windows of a modern sky-scraper--the aeronaut keeping it

afloat for about five minutes by burning wool and straw in a grate made

for the purpose.

Those who have witnessed the reckless manner in which the modern

balloonist mounts thousands of feet into the air, seated on a trapeze

or clinging to flying rings attached to an old balloon, patched and

frequently rotten, may be inclined to sneer at the brave Rozier.

But it should be remembered that in 1783 people had not learned

nineteenth-century contempt for altitude. Furthermore, no one could

tell what might be the effect upon the human system of ascending to a

great height when away from a building or other terrestrial object.

Fainting, hemorrhages, heart-failure, and death had been predicted,

and could not be practically refuted. In short, it was an absolutely

new and untried field; and it required far greater courage on the

part of Rozier to mount eighty feet in a captive balloon than for a

modern aeronaut to sail thousands of feet skyward. In proof of this is

Rozier's subsequent record of ascents in free balloons, and dangerous

voyages, in the last of which he lost his life.

To France, therefore, belongs the honor of inventing the balloon and

being first to test it with a human passenger. On this last point,

however, France only eclipsed America by a few days. For while the

craze for balloon-making was at its height in France during the summer

of 1783, a somewhat similar craze on a small scale had started in some

of the American cities. Two members of the Philosophical Academy of

Philadelphia, Rittenhouse and Hopkins, constructed a peculiar balloon

having forty-seven small bags inflated with hydrogen attached to a car.

On November 28th, six weeks after Rozier's ascent, this balloon was

sent up, with James Wilcox, a carpenter of Philadelphia, as passenger.

Everything was going well with the voyager until he suddenly discovered

that the wind was wafting him toward the Schuylkill River, which so

alarmed him that in attempting to descend quickly he punctured the bags

so freely that he came to the ground with considerable force, escaping,

however, with a dislocated wrist.

Meanwhile, in Europe, a new danger to balloonists had arisen.

Fanaticism was rife, particularly in the vicinity of Paris, and many

members of the cloth were tireless in denouncing this "tampering

with God's laws by invading the inviolability of the firmament."

Fortunately, the king took a broader view, and his soldiers were

supplied freely for protecting balloonists and their property; but even

with this protection both were roughly handled at times.

By this time England had become aroused; balloon-making became popular

across the Channel, and some new records for time and distance were

soon made. One balloon sent up in London landed in Sussex, forty-eight

miles away, making the voyage in two hours and a half. A few days later

a small balloon sent up in Kent was blown across the Channel and landed

in Flanders. But neither of these balloons carried passengers.

As yet there had been few serious attempts at constructing dirigible

balloons, but now Jean-Pierre Blanchard opened a new era of experiments

by combining an ordinary balloon for obtaining the lifting power

with wings and rudder. In this balloon there was also placed an

umbrella-shaped sail interposed horizontally between the car and the

body of the balloon, which was to act as a sort of parachute in case of

accident. On the first voyage in this balloon Blanchard was to have had

for companion a Benedictine monk; but as the machine began to rise from

the ground the monk was seized with fear, turned deadly pale, crossed

himself, and seemed about to collapse. Fortunately at this moment a

leak was discovered in the balloon and it was accordingly lowered for

repairs. When these were completed the aeronaut decided to dispense

with the company of the monk, who was only too willing to gratify his

wish. But just as the car was again ready to start, a stripling student

from the Military Academy forced his way through the crowd, jumped

into the car, and announced his intention of making the ascent. Being

ordered from the car by Blanchard, he declared that he had the king's

license, and when asked to produce it he drew his sword, declaring that

this was the license he referred to. By this time the crowd had lost

patience; some one seized the young man unceremoniously by the collar,

hauled him from the car, and turned him over to the police.

A few years later particular attention was called to this incident by a

rumor, which finally grew into a fixed belief in France, that the young

military student in question was none other than the youthful Napoleon

Bonaparte, then a student at the Academy. Throughout the entire reign

of the emperor this was the general belief, and if it was denied at all

by Napoleon, the denial was not made with due emphasis. At St. Helena,

however, the captive emperor finally stated definitely that he was not

the hero of this escapade, who is now known to have been a student by

the name of Chambon.

Nothing of importance came of Blanchard's first attempt at guiding

a balloon with rudder and wings, except perhaps to emphasize the

fact that wings of an oarlike type were useless for propulsion; but

nevertheless Blanchard soon prepared a somewhat similar balloon in

which he proposed to steer himself across the English Channel. Before

this time, as will be remembered, several balloons had crossed the

Channel, but none of them had carried passengers. On this voyage

Blanchard proposed to make the attempt, taking with him as companion

an American physician named Jeffries. On January 7, 1785, these two

embarked from the cliffs of Dover, a strong wind at the time setting

toward the French coast. Before their journey was half completed they

discovered that an insufficient amount of ballast had been shipped,

and that the balloon was gradually descending at a rate which would

land them in the Channel several miles from shore. To avert this

calamity they were obliged to throw out everything in the car--books,

provisions, anchors, ropes, the "wings" that were intended for guiding,

and also most of their garments. They were, indeed, about to cut loose

the car itself, and climb into the shrouds, when suddenly the balloon,

caught by a fresh current of air, began to rise, and was wafted to a

safe landing place. This was the most daring exploit as yet performed

by the aeronauts.

Although at least fifty different persons had made more or less

extended aerial voyages during the two years that had intervened since

the invention of the first balloon, no one of them had been seriously

injured. Indeed, this apparently most dangerous undertaking had been

relegated to the grade of commonplace in popular opinion, owing to

these fortunate results. But the world was soon to learn that its first

estimates of the dangers of ballooning had not been exaggerated.

Since the invention of the Montgolfier balloon two distinct schools

of balloonists had arisen, one of which favored the hot-air, and the

other the hydrogen balloon. By the advocates of the hot-air balloon it

was claimed that the relatively small expense, and the fact that the

balloonist could descend at any time and renew his supply of fuel, made

this the most desirable type, at least for long-distance voyages. By

the advocates of the hydrogen balloon it was shown that the hot-air

balloon must be constructed much larger to obtain the same amount of

lifting power, could be maintained in the air for a comparatively short

time at most, and was in constant danger from the fire that must be

kept burning in the grate. In reply to this last charge the hot-air

advocates pointed out that a tiny spark of electricity, which would not

affect the hot-air balloon, might explode the hydrogen balloon, thus

introducing an element of danger quite as great as that of the fire in

the hot-air balloons.

As an outcome of these disputes, Pilatre de Rozier, the first man

ever to make an ascent, proposed to attempt to cross the Channel in a

new-type balloon, a combination of hot-air and hydrogen machine, which

was supposed to represent the good qualities of both types. Several

months were consumed in constructing it, and when finally completed he

and a companion attempted to cross the Channel, as had been done by

Blanchard and Jeffries a short time previously. All went well at first

and the balloon was several miles on its journey when suddenly the

wind changed, the balloon was blown back over the heads of the anxious

watchers below, and when a short distance inland, suddenly burst into

flames. At first it descended with an oscillating movement, and then,

freed from the restraining silk and canvas, it shot downward, striking

the earth with terrible force, the two occupants being killed. Thus the

man to make the first ascent in a balloon was also the first to lose

his life. Rozier himself seems to have expected some such ending to his

voyages, and just before making his last ascent he remarked to a friend

that, whatever the outcome, "one had lived long enough when one had

added something to humanity."

The fate of Rozier and his companion being known, and the awful

dangers of balloon ascensions thus forcibly brought home, there was a

popular outcry against such attempts and efforts were made to pass

laws forbidding them. But no such demand or suggestion came from the

balloonists themselves. They could point to the fact that, while as yet

the balloon had been of no importance commercially, it had at least

been turned to some account in the field of science, which was simply

a stepping-stone to commercial advancement. It had been the means

of settling forever the question of temperature and rarefaction at

different altitudes, besides numerous less important although no less

interesting subjects.

While it was true that many of the experiments of the aeronauts had

added largely to human knowledge, some of them were both dangerous

and foolhardy. An exhibition of this kind of folly was given by the

Frenchman, Testu-Bressy, who, wishing to test his theory that large

animals would bleed from the nose at a much lower elevation than man,

despite the thicker consistency of their blood, made an ascent mounted

on the back of a horse. On this occasion the aeronaut did not, even

take the simple precaution of tying the horse's feet to the car; and

what seems most remarkable, the animal made the journey without moving

or showing any sign of fear.

[Illustration: AN INTERNATIONAL BALLOON RACE.

This view was taken before the start of an international balloon race

near Berlin. The balloons are of the ordinary non-dirigible type.]

The time was at hand, however, when Montgolfier, who had always

maintained that the true usefulness of the balloon would be in warfare,

was given the opportunity of seeing his contention verified. On the

breaking out of the French Revolution, balloon corps were at once

pressed into the service of the army. Napoleon Bonaparte carried with

him some balloons on his Egyptian campaign, partly for the purpose

of making observations, and partly to impress the Arabs with

the superiority of Christian armies. A school of aeronautics was

established at Meudon, and some fifty young men, sworn to secrecy,

assigned to it. Balloons were constructed, tested, and distributed

among the different divisions of the army, and one of these was used

for reconnoitering the position of the Austrian forces just before

the battle of Fleurus. In the course of the day two ascents were made

in this balloon, which was held captive by several thousand feet of

cable. The second ascent drew the fire of the enemy's cannon, but the

range was too great and no harm was done. Meanwhile the French general,

Jourdain, was furnished most valuable information by these aerial

voyages.

The Revolutionary wars were also responsible, indirectly, for the

invention of the parachute. It will be recalled that even as early as

the fifteenth century, Leonardo da Vinci had conceived the idea of a

kind of parachute; and that Blanchard had a spread-canvas arrangement

to produce a similar effect attached to some of his balloons. It was

not until 1799, however, that the folding umbrella-like parachute was

invented, the inventor, Garnerin, having developed the idea in trying

to devise some means of escape from the fortress of Buda, Hungary,

where he was being kept prisoner after one of the battles in the North

between the Revolutionary forces and the Austrians and Prussians.

Although he did not actually effect his escape in this dramatic

manner, he finally proved that he had not dreamed in vain during his

imprisonment by demonstrating the entire practicality of the parachute.

Garnerin's first practical test of his invention was made in October,

1797, when he ascended to the height of six thousand feet in a balloon

to which was attached a parachute of the ordinary umbrella type still

used. At that altitude he cut loose the balloon which rushed upward

until it exploded, while the parachute, dropping rapidly at first,

finally settled slowly and gently to the earth, without injury to the

inventor.

PROGRESS IN MECHANICAL FLIGHT

The attempts at navigating a balloon having proved thus far so

unsuccessful, many inventors now returned to the idea of producing a

flying-machine which was independent of the inflated balloon. It was

evident that the resistance presented by the great surface necessary

in a balloon of sufficient size to have the required lifting power was

such that no known efforts of propulsion could overcome this resistance

even in the face of a slight breeze, to say nothing of a strong wind.

The balloon was by no means abandoned, however, and two definite

schools of aeronauts gradually came into existence, each having ardent

advocates.

As early as 1784, the aeronaut Gérard had proposed a flying-machine

which was to be made with body, wings, and steering apparatus, in

which propulsion was to be accomplished by the use of escaping gas and

gun-cotton. The inventor himself was so sanguine of the results, and so

many contemporary inventors were of the same opinion, that when this

machine proved to be an utter failure, the blow to the advocates of

the flying-machine was so great that they did not rally from it for

something like a quarter of a century. In 1809, however, a Viennese

watchmaker named Degen revived interest in attempts at mechanical

flight by inventing a flying-machine which consisted essentially of two

parachutes. These were worked by hand, and the inventor was said to

have been able to rise to a height of over fifty feet from the ground

"moving in any desired direction."

These claims were not borne out in fact, but they stimulated an

interest in the possibilities of mechanical flight, and in the

parachute, which had never come into popular favor despite its

successful use by the inventor, Garnerin. Hopes were again entertained

that a modification of this device might be utilized in solving the

problem of aerial flight, and in 1837 an aeronaut, Henry Cocking,

invented a new type in which he proposed to descend from a balloon.

The parachute of Garnerin, as we know, had been constructed like a

huge umbrella, whereas Cocking's parachute had the general appearance

of an umbrella held upside down. An unusual interest was aroused in

the prospective experiment from the fact that a great majority of

scientists did not consider that this parachute was constructed on

correct scientific principles, and predicted that the aeronaut would

be killed when he attempted to use it. Before the day of the trial

arrived numerous articles had been published, presenting arguments

for and against Cocking's device, and on the very day itself one of

the newspapers contained a long article by a leading authority on

aerostatics, reviewing the numerous reasons why the attempt would

surely prove a failure.