Walter Le Conte Stevens

“ Montgolfier made several exhibitions of his hot-air balloons at Paris, and in one of these, on the 15th of October, M. Pilâtre de Rozier made the first ascent attempted by a human being. But to Charles is due the credit of making the balloon a moderately safe vehicle in which the aëronaut could ascend or descend at will by varying the relation between the amounts of ballast and of gas retained. Although many thousands of ascents have been made since 1783, the total number of lives recorded to have been lost does not exceed fifty. ”

“ A Siemens electric motor was constructed, weighing but fifty-five kilogrammes. When excited by the current from a battery of twenty-four elements weighing one hundred and sixty-eight kilogrammes, this motor was found capable of doing work equivalent to that of twelve or fifteen men, that is, from seventy-five to one hundred kilogramme-metres per second, continued through three hours, the weight of battery and motor together being but little in excess of the weight of three men. Tissandier devised also important improvements in the method of generating pure hydrogen rapidly on a large scale. ”

“ But, for the development of aëronautics as an art, we must continue to look to France, its earliest home. If stock companies are formed for the manufacture of air-ships, it must be first among those to whom the recent successes have already become a source of pride. Even as toys and as advertising media, balloons have always been more popular in France than elsewhere. ”

“ BALLOONING has thus far been a French art: introduced a little over a century ago by a Frenchman, Montgolfier; rapidly developed by another Frenchman, Charles; more practiced in France than anywhere else in the world ”

“ The history of the application of science to art has revealed a number of cases in which practical success was secured by inventors entertaining quite erroneous conceptions of the principles they were applying. ”

“ The ratio of length to thickness is thus much greater than in Tissandier's balloon. The details of construction of the battery and motor have not been given to the public by Captain Renard. The rudder is almost a parallelogram in form, and thickest in the middle, the cloth being tightly stretched over a light framework so as to present a rigid surface to the air. The propeller is fixed to the extremity of a long shaft, and placed at the front, instead of rear, of the balloon. The front end of the machine is thicker than the rear end. ”

“ The city of Paris has for years past included one or more large establishments devoted exclusively to the manufacture of them. Should "dirigeable" balloons ever become of commercial importance, enterprising Americans will be quick to imitate their French neighbors, and put upon our market all that the public may demand. The day is perhaps not far distant when at least a favored few in our own country may enjoy the luxury of summer afternoon excursions through the air, free from dust and cinders, and occasionally even vying with the birds in speed. ”

“ At best, however, the balloon as a means of locomotion is of more interest from a scientific than commercial standpoint. Increasing experience will determine the best disposition to be made in relation to a variety of points that are still open to discussion, such as the best methods of reducing resistances and increasing the efficiency of the motor. ”

“ A second ascent was accomplished by him in 1855, but under unfavorable conditions. He made no further attempts with this machine, the abandonment of these experiments being due chiefly to their danger. A steam-engine, sending forth sparks beneath a mass of thirty thousand cubic feet of inflammable gas contained within an envelope of thin cloth, is a source of peril to which few men would be willing to expose themselves, even if lofty elevations were not reached. Trouble also resulted from the fact that the weight of the balloon could not be kept constant. ”

“ On rising high above the ground the direction of aërial currents is often found to differ greatly from that of the surface-currents. Rising above the clouds, the aëronaut may lose sight of the earth and be carried at a rate of which he is totally unconscious, there being no means of measuring his speed when borne along with a current to which the balloon opposes no sensible resistance. By noting the times and places of ascent and descent, the rate has been estimated to exceed that of our fastest railroad-trains ”

“ His immense balloon, containing one hundred and twenty thousand cubic feet of pure hydrogen, was nearly similar in shape to that of Giffard. The car beneath was capable of carrying easily fourteen men, seven of whom at a time were employed in working a capstan which controlled the shaft of the propeller, each of the two blades of this being about ten feet in length. On February 2, 1872, Dupuy de Lôme ascended in this balloon, and attained a speed estimated at 2·8 metres per second, equivalent to about six miles per hour. By means of the rudder he changed the direction through an angle of 12°. ”

“ The enormous expense attendant upon the construction and manipulation of an aërostat capable of carrying even so few as a score of persons forbids competition with railroads and steamships. The high-tension battery, which is at present the most available source of energy to give motive power, has an effective life of only a few hours ”

“ Above it, and farther back, is a triangular sail, to be manipulated as a rudder. On October 8, 1883, the first ascent was made. The air at the ground was calm, but on reaching a height of sixteen hundred feet the wind was blowing at the rate of rather more than six miles an hour. On putting the propeller into action, with a velocity of three revolutions per second, and turning the head of the aërostat against the breeze, it was kept motionless for some minutes; but the rudder soon proved to be insufficient to keep the direction constant, flapping like a sail, and at times
Fig. ”

“ The ascensive force of this gas when pure is about seventy-five pounds per thousand cubic feet, or eleven hundred and eighty grammes per cubic metre; while that of coal-gas which has been most generally employed for ballooning purposes is not more than five eighths as much. By the substitution of hydrogen, the size, and consequently the expense, of the balloon is correspondingly diminished.
The aërostat constructed by M. Albert Tissandier is shown in Fig. 3. ”

“ On the basis of the success already attained, calculations have been made which indicate that it may be quite possible in the near future to construct larger balloons that will travel in calm air at the rate of twenty-five or thirty miles an hour. ”

“ Giffard had attained an estimated speed of four metres per second, or nine miles per hour. Muscular power was thus shown to be far too uneconomical, while steam was too dangerous, to be employed in the direction of aërostats.
It was not until 1881, the year of Giffard's death, that electricity was applied as a motive power in the attempt to solve the difficult problem with which he had grappled. His pupil, M. Gaston Tissandier, [1] had early imbibed a passion for aëronautics, and made many successful ascents with spherical balloons. ”

“ He constructed a small experimental balloon, which was filled with hydrogen, the effective ascensional force being two kilogrammes. A motor, of the Siemens type (Fig. 2) , weighing only two hundred and twenty grammes, was made to turn the propeller, which consisted of a pair of vanes, each ten centimetres long; storage-cell, motor, and propeller being supported on a light platform suspended by netting. This ”