having treated of the balloon in all its different aspects, it is both just and appropriate to conclude with an account of the theory and construction of that curious machine which is, according to some enthusiastic aeronauts, to supplant the balloon altogether, and enable us to accomplish that which has been one of the great aims and desires of mankind from the earliest ages, namely, the directing of our flight, or steering a course, not only through, but, if need were, in opposition to the winds.

monsieur nadar being, perhaps, the most zealous advocate of this machine, we draw our information chiefly from his writings. of course the reader will understand that we do not support the views which we are about to set forth; neither, however, do we treat them lightly, because we have lived long enough to see proposals which, not many years ago, would have been deemed worthy of the most visionary of lunatics, carried out to a successful issue and reduced to sober facts.

when we hear of a flying machine which is to rise from the earth at the bidding of man, and, like the fabulous creations in the arabian nights’ entertainment, dart through the air with passengers and luggage bound for definite localities, turning hither and thither, or alighting on the earth according to the will of a steersman—we confess to a feeling which is apt to wrinkle our visage with the smile of incredulity; but we sternly rebuke the smile, for we know that similar smiles wreathed the faces of exceedingly wise people when, in former days, it was proposed to drive ships and coaches by steam, and hold instantaneous converse with our friends across the atlantic by means of electricity!

let us therefore gravely consider the aerial locomotive.

monsieur nadar, as the reader already knows, scouts the idea of steering balloons.

in reference to this he states with truth that, “a balloon which presents to the action of the atmosphere a volume of from 22,000 to 42,000 (cubic) feet of a gas from ten to fifteen times lighter than air, is, by its very nature, smitten with incapacity to struggle against the slightest current, no matter what may be the resisting motive force which may be imparted to it. both by its constitution, and by the medium which drives it hither and thither at the pleasure of the winds, it can never become a vessel. it is a buoy, and remains a buoy.”

discarding, therefore, with contempt, the balloon as an aerial locomotive, he announces his belief that it is the screw which is destined to drive us, or clamber with us, into the blue vault above, and convey us from place to place. and here it is right to assure the reader that the theoretical power of the screw to accomplish the end in view is not a disputable question. it has been practically proved by models, and the only point that remains to be settled is the possibility of applying the power to machines large enough to carry human beings with a sufficient degree of safety to warrant risking the attempt.

monsieur nadar sets out with a statement which he deems self-evident, namely, that, “in order to contend against the air, we must be specifically heavier than the air”—a truth which was also, we are told, announced by the first napoleon in the epigrammatic sentence, “there can be no progress without resistance.” from this the frenchman proceeds to prove that, in order to command the air, it is necessary to support one’s-self upon it, instead of being at its mercy; that we can only rest upon that which resists, and that the air itself furnishes us amply with the needful resistance—it being “the same atmosphere which overturns walls, tears up by the root trees a century old, and enables ships to ascend impetuous currents.” glowing with the ardour of a man whose faith is refreshingly great, he tells us that the time has at last come when the atmosphere must yield to man. “it is for man,” he says, “to restrain and subdue this insolent and abnormal rebellion, which has for so many years laughed at our vain efforts. we are in turn about to make it serve us as a slave, just as the water on which we launch the ship, as the solid earth on which we press the wheel!”

there is a toy called the spiralifer, which is common enough in towns, and which is, doubtless, known to almost every one. it consists of four flat fans attached to a spindle somewhat after the manner of the arms of a windmill. it is placed in a hollow tube and made to spin violently by pulling a string wound round the spindle. the result is that the spiralifer leaps out of the hollow tube and ascends powerfully as long as the violent spinning motion continues. if properly constructed, this toy acts with great force and certainty, and if the spinning motion could only be kept up, by any means, the ascent would be continued. the principal here involved is precisely the same as that which causes a windmill to turn, a screw-propeller to drive a ship, and a cork-screw to enter a cork. it is pressure against a resisting medium. air is the resisting medium in the case of the mill; water and cork respectively in the other cases. the only difference between the windmill and the spiralifer is, that the first is moved by the air pressing against it, the other by itself, in its rotatory action, pressing against the air. if you turn a bottle upside down, and, while in that position, send a cork-screw up into the cork, you set in motion the same force which is applied in the spiralifer. as the screw screws itself up into the cork, so the spiralifer screws itself up into the air. of course the screw remains sticking there when the motive power ceases, because of the density of the medium through which it moves, while the spiralifer, when at rest, sinks, because of the fluidity of the air; but the principle of motion in each is the same. the screw-propeller of a ship is just a spiralifer placed horizontally, acting on water instead of air, and having a vessel placed in front of it.

now, monsieur nadar’s aerial locomotive is a huge spiralifer, made strong enough to carry up a steam-engine which shall keep it perpetually spinning, and, therefore, perpetually ascending. perhaps we should have said that his locomotive is a huge machine to which several spiralifers are attached, so that while one set raises or (by reversing the engine) depresses it, other sets drive it sideways. the theory is perfect, and the practice has been successfully attempted in models. messieurs ponton d’amécourt and de la laudelle, we are told—“the one a man of the world, and the other a man of letters”—engaged the services of two skilled mechanics, messieurs joseph of arras and j. richard, who constructed models of machines which ascended the atmosphere, carrying their motive power (springs) along with them.

besides horizontal screws, it is proposed to furnish additional guiding power to the locomotive by means of inclined planes. these, by being arranged in various positions, while the machine is in motion, would act on the air, as do the wings of a bird, and give it direction.

no doubt, despite the simplicity of all this, difficulties will present themselves to most minds, some of which may perhaps bulk very large in the minds of mechanicians—such as the power of materials to withstand the violence of the forces to which they are to be applied, etcetera. we do not know; however, no difficulties seem to have afflicted monsieur nadar, who thus grandly waives them all aside, and revels in the contemplation of the triumphant flights that lie before him in the future:—

“it will be understood,” he writes, “that it belongs not to us to determine at present either the mechanism or the necessary manoeuvres. neither shall we attempt to fix even approximately the future velocity of the aerial locomotive. let us rather attempt to calculate the probable velocity of a locomotive gliding through the air, without the possibility of running off the rails, without any oscillation, without the least obstacle. let us fancy such locomotive encountering on its way, in the midst, one of those atmospheric currents which travel at the rate of forty leagues an hour, and following that current; add together these formidable data, and your imagination will recoil in adding still further to these giddy velocities, that of a machine falling through an angle of descent of from 12,000 to 15,000 feet in a series of gigantic zigzags, and making the tour of the globe in a succession of fantastic leaps.”

truly monsieur nadar seems to us to be right! there are few men or women, we suspect, who would not recoil from such “fantastic leaps,” and unless the prospect of a more sedate style of travelling be held out, it is not probable that aerial locomotives will receive much patronage from the general public.

lord carlingford, who mistook the sentiments of monsieur nadar in regard to the aerial locomotive, claimed for himself, in 1863, the honour of having previously invented and successfully launched an aerial chariot, weighing seventeen stone, which rose on the air without any assistance but that of the wind, and, having arrived at a horizontal position on the air, it remained stationary there until pulled down.

monsieur nadar, at the conclusion of a courteous letter in reply to this claim, gives his intentions and opinions on the subject pretty clearly as follows:—

“in fine, and that there may be no possible mistake on the part of any one regarding what i am attempting, i desire to find the necessary resources for the constitution of a society, which shall be the centre of all hitherto isolated and therefore lost attempts to solve a question so profound, so vast, so complex that it does not seem to belong to a single individual to achieve it. i have my system, which i believe to be good, since it is mine; but i shall aid with all the strength of my will, and with all the energy of my perseverance, every system which shall be proved to be better than mine. the question to me is not at all who may have determined the great problem; it is that the solution may be found at last. the fruit is ripe; i long to see it plucked, no matter by whom; and this is the sole cause of the agitation which i have endeavoured to call forth, and which i am now pursuing.”

a man who takes up a subject with such hearty enthusiasm, and in such a liberal spirit, is, we hold, entitled to the utmost respect. as we have, however, done our best to lay his case before the public, we feel entitled to express with all humility some of the doubts which have been suggested to our own mind while meditating on the subject.

no doubt the theory propounded is correct, and, as carried into practice with models, the aerial locomotive has been a great success. no doubt also it is pleasant to contemplate the possibility of traversing space like a bird, a meteor, or a comet, and the absolute impossibility of “getting off the rails;” but what, we would ask, would be the result of a hitch—ever so small—in the working of the steam-engine or of the spring motor?

if a railway engine breaks down, there are all sorts of chances of escape open to the traveller. the engine may not quit the rails, or it may bound off alone, snap the coupling chains and leave the carriages to run until they come to a gradual standstill; or, the concussion may be so modified that no serious injury may result; or, should it come to the worst, the traveller may be among the fortunate number who make “miraculous escapes.” but if a crank of an aerial machine should snap while it is careering through space, or even a screw get loose and cause a momentary stoppage of the motor, it is abundantly evident that escape from total and swift destruction would be “miraculous” indeed, for the whole affair would come to the ground like a thunderbolt, and “leave not a wrack behind!”

probably it might be answered in reply that a parachute attached to the machine, or the inclined planes acting as a parachute, would moderate the descent. well, there may be something in that; nevertheless, parachutes have not yet proved themselves to be very trustworthy,—and we are constrained to reiterate the fact, that while an accident causing the break-down of the motive power of a steamboat or a railway carriage does not necessarily involve fatal consequences, an accident which should stop the motive power in an aerial locomotive would almost to a certainty, result in a grand smash, which would involve machine and passengers in one inconceivable whirl of chaotic destruction.

whether this machine shall ever be successfully completed or not, it is evident that it still engages the earnest attention of men, as we gather from the following paragraph recently published in the san francisco bulletin:—

“at a meeting of the aerial navigation company, held on friday, july 24, 1869, in san francisco, it was voted to raise the necessary funds to construct an improved avitor of large size. the opinion of the engineers of the company was unanimous as to success so far, and the feasibility and success of the projected flying-ship. it will be about 150 feet in length, 20 to 40 feet diameter of the gasometer, with propelling blades on each side of the centre, describing a radius of about 16 feet. the propellers are shaped like a steamship’s, with two blades, each very light. they will be driven by a steam-engine of five-horse power, weighing, with boiler connections and water, 430 pounds weight. the planes on each side for floating the machine will be about twenty feet wide at the centre of the machine, and made in sections, so that they can be depressed or elevated at pleasure with the rudder or tail. the gasometer will be made in sections, so that in the event of accident to one section, the remainder will be sufficient for all practical purposes; indeed, it is claimed that the ship can fly through the air with such speed that the sustaining power of the planes alone will be sufficient to maintain the avitor in mid-air. the gasometer will be made, probably, of thin muslin or silk, saturated with gutta-percha. it is to carry four persons, and will be ready for trial in sixty or ninety days. the result of this experiment will be looked for with great interest all over the country.”

the americans, with that vigour of conception and promptitude in action for which they are celebrated, have done a good deal in the cause of aerostation; but, as their doings and experiences have been in many respects similar to those men whose voyages have been already recounted or touched upon, it would involve too much repetition to detail them here. some of their attempts, however, have outshone those of the men of the eastern hemisphere. for instance, mr j. wise, a noted aeronaut, has several times exploded his balloons while in the air, to show that the fragments with net-work form a sort of parachute which moderates the descent. he also, with mr la mountain and others, accomplished in 1859 the longest flight on record, namely, 1150 miles in less than twenty hours; and the latter gentleman did 300 miles in four hours in the same year. another american, mr lowe, made an enormous balloon, with which he resolved to cross the atlantic in about 48 hours. we await the accomplishment of this feat with much solicitude!

in conclusion, we may say that the subject of aerostation is still in its infancy, and that we have still to learn how to conduct ourselves properly when—up in the clouds.

the end.