212 THE LANGLEY AEEODKOME. 



flight downward, or under them, directing it upward, and to wreck the 

 experiment. When the cause of the difficulty was found, the cure 

 was not easy, for it was necessary to make these great sustaining sur- 

 faces rigid so that they could not fjend, and to do this without making 

 them heavy, since weight was still the enemy; and nearly a year passed 

 in these experiments. 



Has the reader enough of this tale of disaster? If so, he may be 

 spared the account of what went on in the same way. Launch after 

 launch was successively made. The wings were finally, and after infi- 

 nite patience and labor, made at once light enough and strong enough 

 to do the work, and now in the long struggle the way had been fought 

 up to the face of the final difiiculty, in which nearly a year more passed, 

 for the all-important difiiculty of balancing the aerodrome was now 

 reached, where it could be discriminated from other preliminary ones, 

 which have been alluded to, and which at first obscured it. If the 

 reader will look at the hawk or an}'^ soaring bird, he will see that as 

 it sails through the air without flapping the wing, there are hardly 

 two consecutive seconds of its flight in which it is not swaying a little 

 from side to side, lifting one wing or the other, or turning in a way 

 that suggests an acrobat on a tight rope, only that the bird uses its 

 widely outstretched wings in place of the pole. 



There is something, then, which is difficult even for the bird in this 

 act of balancing. In fact, he is sailing so close to the wind in order 

 to fly at all that if he dips his head but the least he will catch the wind 

 on the top of his wing and fall, as I have seen gulls do, when they 

 have literally tumbled toward the water before they could recover 

 themselves. 



Besides this, there must be some provision for guarding against the 

 incessant, irregular currents of the wind, for the wind as a whole — 

 and this is a point of prime importance — is not a thing moving along 

 all of a piece, like water in the Gulf Stream. Far from it. The wind, 

 when we come to study it, as we have to do here, is found to be made 

 of innumerable currents and countercurrents, which exist altogether 

 and simultaneously in the gentlest breeze, which is in reality going 

 fifty ways at once, although, as a whole, it may come from the east or 

 the west; and if we could see it, it would be something like seeing the 

 rapids below Niagara, where there is an infinite variety of motion in 

 the parts, although there is a common movement of the stream as a 

 whole. 



All this has to be provided for in our mechanical bird, which has 

 neither intelligence nor instmct, without which, although there ])e all 

 the power of the engines requisite, all the rigidity of wing, all the req- 

 uisite initial velocity, it .still can not fly. This is what is meant by 

 balancing, or the disposal of the parts, so that the air ship will have a 

 ■position of equilibrium into which it tends to fall when it is disturbed, 



