ap:rial navigation. <' 



ByO. ClIAXUTE, (Itiriujo, III. 



There are now dawnings of two possible solutions of the prol)lem 

 of aerial navigation, a pi'obleni which has impassioned men foi- per- 

 haps four thousand or live thousand years. Navigii))le l)alloons have 

 recently l)een developed to what is believed to be nearly the limit of 

 their efficiency, and after three intellio-cMit but unfortunate attempts 

 by others a successful dynamic tlying machine seems to have been 

 produced ])y the Messrs. Wright. 



It is therefore interesting to review the present status of the ques- 

 tion, the prospects of its solution, and the probable uses of the hoped- 

 for air slii])s. 



BALLOONS. 



As to balloons, we may pass over the early gropings and failures to 

 make them navigable. It was recognized very soon that the spherical 

 balloon was tlie sport of the wind; that it was necessary to elongate it 

 in order to evade the resistance t)f the air, and that, inasnuich as aerial 

 currents are nuich more rapid than acpieous currents, it was necessary 

 to obtain considerable speeds in order to have a useful air ship. This 

 means that there nuist be great driving power and that this power 

 shall weigh as little as possible, for in any case the balloon itself, with 

 its adjuncts and passengers, will absorl) the greater part of its lifting 

 power. 



Gitfard was the tirst to apply, in ltSr)2, an artificial motor to an elon- 

 gated balloon. This motor consisted in a steam engine of o horse- 

 power, which weighed with its appurtenances 402 pounds, and Gifl'ard 

 o})tained only (J. 71 miles per hour, although his balloon was l-i-l feet 

 long- and 39 feet in diameter, or about the size of a tramp steamer. 



Dupuy de Lome in 1872 went up with a balloon 118 feet long and 

 49 feet in diameter, but, having a wholesome dread of the contiguity 

 of fire and inflammable gas, he emploj^ed man power (weighing- about 

 2,000 pounds to the horsepower) to drive his screws, and he obtained 



"Paper read before .Section D, Anu^rican Association for the Advaiiceinont of 

 Science, December 80, 190;!. I'ulilislu'd hv permission of tlie author. 



173 



