STORY OF EXPERIMENTS IN MECHANICAL FLIGHT. 177 



gentle intermittent breeze (probably not more than 3 or 4 miles an 

 hour) was sufficient to make it impossible even to prepare to drop the 

 aerodrome toward the water with safety. 



It is difficult to give an idea in few words of the nature of the 

 trouble, but unless one stands with the machine in the open air he can 

 form no conception of what the difficulties are, which are peculiar to 

 practice in the open, and which do not present themselves to the con- 

 structor in the shop, nor probably to the mind of the reader, 



December 1, another failure; December 7, another; December 11, 

 another ; December 20, another ; December 21, another. These do not all 

 involve a separate journey, but five separate trips were made of a round 

 distance of 60 miles each before the close of the season. It may be 

 remembered that these attempts were in a site far from the conveniences 

 of the workshop and under circumstances which took up a good deal 

 of time, for some hours were spent on mounting the aerodrome on each 

 occasion, and the year closed without a single cast of it into the air. 

 It was not known how it would have behaved there, for there had not 

 been a launch even in nine trials, each one representing an amount of 

 trouble and difficulty which this narrative gives no adequate idea of. 



I pass over a long period of subsequent baffled effort, with the state- 

 ment that numerous devices for launching were tried in vain and that 

 nearly a year passed before one was effected. 



Six trips and trials were made in the first six months of 1894 with- 

 out securing a launch. On the 24th of October a new launching piece 

 was tried for the first time, which embodied all the requisites whose 

 necessity was taught by previous experience, and, saving occasional 

 accidents, the launching was from this time forward accomplished with 

 comparatively little difficulty. 



The aerodromes were now for the first time put fairly in the air, and 

 a new class of difficulties arose, due to a cause which was at first 

 obscure — for two successive launches of the same aerodrome, under 

 conditions as near alike as possible, would be followed by entirely dif- 

 ferent results. For examj)le, in the first case it might be found rush- 

 ing, not falling, forward and downward into the water under the 

 impulse of its own engines; in the second case, with every condition 

 from observation apparently the same, it might be found soaring u]3ward 

 until its wings made an angle of 60 degrees with the horizon, and, 

 unable to sustain itself at such a slope, sliding backward into the 

 water. 



After much embarrassment the trouble was discovered to be due to 

 the fact that the wings, though originally set at precisely the same 

 angle in the two cases, were irregularly deflected by the upward ]3res- 

 sure of the air, so that they no longer had the lorm which they appeared 

 to possess but a moment before they were upborne by it, and so that a 

 very minute difference, too small to be certainly noted, exaggerated by 

 this pressure, might cause the wind of advance to strike either below 

 SM 97 12 



