THE GREATEST FLYING CREATURE. 651 



the Pterodactyl., This may have been quite 20 feet from tip to tip of 

 wine. The paleontologist says that approximately the wing surface 

 was 25 square feet, the weight something like 30 pounds, and 1 inter 

 from the consideration just quoted that the power whs probably loss 

 than 0.05 horsepower; the immensely greater economy and efficiency 

 of nature in the respect of power being most strikingly shown by the 

 L of the small rectangle as compared with that in the flying machine 



of man's invention. , , 



\fter this comes the condor, preeminently a soarer. Its stretch oi 

 wine is 9 to 10 feet, its supporting area very nearly 10 square feet, 

 its weight IT pounds, and the approximate horsepower it develops 

 (inferred from the facts already stated) scarcely 05, 

 1 Next comes the turkey buzzard, whose stretch of wing is 6 feet, 

 its supporting area a little over 5 square feet, its weight 5 pounds, 

 and the approximate horsepower it develops (as above) 0.015. 



All the above are soaring birds. 1 now pass to another oidei of 

 birds, which flap their wings. The wild goose, with a supporting 

 area of 2.7 square feet, has a weight of 9 pounds, and needs a propor- 

 tionately greater power of nearly 0.026 horsepower to drive it, as 

 ao-ainst scarcely 0.02 horsepower in the last example 

 "Next we have another familiar bird, the pigeon, which drives itself 

 bvflappingthe wings. This has an area of about 0. 7 ot 1 square toot, 

 a'weioht of 1 pound, and a horsepower of 0.012. 



Below this we come to the humming bird, whose area, being shown 

 on the same scale as the others, is almost too small to be ^mpiutod 

 on the pace, but which has a supporting surface ot nearly .03 ot 

 a square fo'ot, a weight less than 0.02 of a pound, and a horse- 

 power of probably not over 0.001. (All these values, as we have 

 already said, are but approximative.) 



Particular attention is to be paid to the fact that regarding the 

 ratios of supporting surface to weight supported, these ratios are no 

 only not the same in all the birds, but themselves differ greatly, but 

 systematically, with the absolute weight. If we inquire ,how _much 

 l" horsepower would support, for instance supposing the rah so 

 sustaining surface (i. e., wing area) to weight to be constant we find 

 that 1 horsepower would, in the flying machine, support 20 pounds 

 with 36 square feet area of wing (i. e., If square feet to a pound); 

 and that, passing to the flapping birds, if the wild goose were to pre- 

 serve the same illations on an enlarged scale, its 1 horsepower would 

 support 346 pounds of weight with the use ot 101 square feet ot wing 

 surface or 29 square feet to the pound; that in the pigeon 1 horse- 

 power would support 83 pounds of weight with the use ot : ofc , «juare 

 feet of wing surface or 0.7 square feet to the pound and that in the 

 humming bird 1 horsepower would support 15 pounds ot weigh with 

 the use of 26 square feet of wing surface or 1.73 square feet to he 

 pound. So that, broadly speaking, so far as these tew examples go, the 



