126 RECENT AERONAUTICAL PROGRESS. 



Passing from the balloon — that is to say, any apparatus which dis- 

 places a volume of air weighing as much as or more than its own 

 weight (and many thoughtless inventors are apt to neglect this defini- 

 tion) — we find several different types of machmes which show promise 

 of success. 



Beginning with the simplest, we have the gliding or soaring machine. 

 One of the greatest paradoxes in nature is soaring flight. I have said 

 how doubtful many people might be about aerial navigation if they 

 had never seen a })ird fly, but we can confidently assert that no man 

 would believe it possible for a bird to maintain itself for hour after 

 hour in mid-air without the slightest movement of its wings were the 

 actual demonstration of it not visible every day. I will not now enter 

 on a discussion as to how this is accomplished, but will only say that 

 there are inventors who hope to be able to emulate the albatross and 

 soar away into the heavens without any motive power or propeller. 

 It seems so paradoxical that many laugh the idea away. But the hard 

 fact remains that birds can do it, and therefore why not men^ I 

 received a lettei- only a few days ago from Mr. O. Chanute, than whom 

 there is probably no greater authority living on soaring flight. He 

 sa3^8 that he had just returned from witnessing this season's gliding 

 experiments of the Brothers Wright, and that "they have made a 

 very considerable advance since last year, and now glide at angles of 

 6° to T'-", sustaining 125 to 160 pounds per net horsepower. Wright 

 is now doing nearly as well as the vulture, is not far from soaring 

 flight, and I am changing my views as to the adA'isability of apph'ing 

 a motor." 



I think this is a n)ost remarkable statement, and there realh" seems 

 no reason why such experts, having attained proficiency in the delicate 

 art of balancing themselves according to the various puffs and currents 

 of air, should not be able to soar away on the wings of the wind and 

 remain indefinitely in mid-air. 



The next general type of apparatus tiiat I may refer to is that of 

 rising in the aii' by means of a screw proptdier mounted on a vertical 

 shaft W^e all have seen little toys ascend in the air working on this 

 principle. A large machine of this sort was recently constructed in 

 Paris. l)at the exp(M-iments of Mr. W. (t. Walker, of carefully tt^sting 

 the thrust and lifting powei- of various screws, have Ix^en among the 

 most important conti'ibutions to this science. He has clearly shown 

 that it is possil)l(> to practically obtain a thi'ust of 25 })ounds per horsc- 

 powiM'. As engines art^ now made weighing no more than 1(> })oiuids 

 per horsepower, it is dearly denioiisti'able that a niacliine on this prin- 

 ciple coidd be construct(^d to lift itself", carrying some 15 pounds per 

 horsepower over and al)o\(^ llu^ w(Mght of the (Migines. Even if not a 

 practical form of machine for tra\M'ling thi'ough the air. it would l)e a 

 most interesting experiment to try. 



