THE EMPIRE OF THE Mil. 413 



every day? The bird works no magic, he does not viohite natural hiws. 

 We have not as yet rigorously explained these multifarious dccomposi- 

 tious of forces because they are all complicated by movement and by 

 life; but they are demonstrated each instant, and they constantly invite 

 us to imitate a mode of motion which can not be beyond our attributes 

 any more than the feats of e<piilibrium which we perl'orm uiu'onsci(msly 

 every moment of our lives. 



We appreciate well enough the acts of walking, of leaping, of gym- 

 nastics, of the velocipede: have the manteuvers which maintain their 

 stability been calculated mathematically? No, they have not. Our 

 vital instinct suiSces for such action, not only accurately, but with all 

 rapidity required by the need. Thus will it be assuredly for that remain- 

 ing problem of ecjuilibrium which resembles the others so greatly — the 

 sailing on the wind; for man's life, that wondrous reservoir of uncon. 

 scious science, will certainly prove equal to this new achievement. 



The main requirement will be skill. The knowing how, and when, 

 and why, each act is to be performed, to be expert in all possible njan<eu- 

 vers required to produce various results or to meet contingencies; in 

 tine, the man must thoroughly know his ])usiness — as a bird, a soaring 

 bird, just as he knows in time his business as a swimmer, a skater, a 

 bicycle rider, an acrobat — and, in short, as an expert in any gymnastic 

 exercise. 



Si><(i<l of the trl)id. — For the sailing birds, the wind is the source of all 

 good gained while sustained. Xo wind, no uprise, no sailing flight pos- 

 sible; therefore, in a dead calm, they are all on the i)erch. Now, what 

 least velocity of wind can support and upraise the most exi>ert soaring 

 birds ? 



Observers may fancy they see kites and vultures as(;emiing in dead 

 calm. 'Tis an impossible feat. There must absolutely be, at a certain 

 height, a cnrrent in the air, perhaps indiscernible to the eye, but nev- 

 ertheless revealed to the experienced observer by the bird's mameuvers. 



The sailing bird, rising during a calm, generally Haps his wings till 

 he is up one hundred yards. At that elevation he begins to circle, 

 ]>artly gliding partly flapping; then he diminishes his beats as the ele- 

 vation increases, and finally stops them altogether; this proves that 

 the air is motionless only near the ground. 



It is w<'ll known that there is almost always a strong cnrrent of air 

 at prominent altitudes; we leave the valley where absolute stillness 

 reigns, and on the mountain top we find a lively bree/.e. A light /ephy r, 

 fanning the sitring-li'vc day, which we can not miscall a w ind, is blowing 

 however a hundred yards above, some twenty two miles per honr, as 

 proved by accurate observations made by myself. l»y lueans of buisting 

 lin'-works, bombs, whose smoke is most sensitixc. 



When the wind isde(;idedl> ])erceptil)Ie at the surface of the gronnd, 

 it greatly exceeds twenty-tw(» miles an honr at an altitude of 1,0()(> 

 feet. A "ood wind, a fresh sea ])ree/e, one in which the sailoi- t.ikes 



