868 EEPOBT— 1893. 



own bodily powers. It is said that a certain man fitted himself with apparatus in 

 the time of James VI. of Scotland, and actually precipitated himself from the cliff 

 below Stirling Castle, in sight of the king and his courtiers ; but the apparatus 

 coUap.sed, and he broke his leg, and that was the end of the experiment. 



But why should not man fly ? It is not that he does not desire to do so. For 

 every denizen of our precarious British climate, when he has noticed the ease with 

 which swallows and other migratory birds fly off on the approach of winter, 

 hundreds and even thousands of miles to the sunny south, must have wished he 

 could do the same. One reason why we cannot fly, even with artificial aids, such 

 as wings, is that, as in the case of the penguin or the ostrich, our bodily mechanism 

 is specialised and our muscular power diffused in other directions, so that we 

 could not actuate wings of sufficient area to carry us even if we had them. 



M. de Lucy, a French naturalist, has shown that the wing-area of flying 

 animals varies from about 49 square feet per lb. of weight in the gnat, and 5 square 

 feet in the swallow, to half a square foot per lb. of weight in the Australian crane, 

 which weighs 21 lb. and yet flies well. If he were to adopt the last or smallest 

 proportion, a man weighing 12 stone would requii'e a pair of wings each of them 

 14 feet long by 3 feet broad, or double the area of an ordinary room door, to carry 

 him, without taking into account the weight of the wings themselves. 



In flying birds there is a strong tripod arrangement to secure firm points of 

 attachment for the wings, and a deep keel in the breast-bone, to which the large 

 pectoral muscles are secured. Think of the wings I have described and the 

 absence of pivots, keel, and muscles in man, and it will be tolerably obvious why 

 he cannot fly, even with artificial wings. 



But it might be contended that a man's strength is in his legs rather than in 

 his arms, and that it is conceivable that a successful flying-apparatus might be 

 made if adapted for the most, instead of the least, favourable application of his 

 bodily strength. 



According to D. K. Olark,^ a labourer working all day exerts on an average 

 •13 horse- power. The maximum power of a very strong man for a very short time 

 is "46 horse-power. 



According to Dr. Haughton,'^ the oarsmen in a boat-race of 1 mile, rowed in 

 7 minutes, exerted each '26 horse-power. 



Suppose we take the rowing case as the maximum maintainable for, say, 

 7 minutes by a man weighing 168 lb. Then in flight he would have to sustain 

 a weight of 



1*^=046 lb. 

 •26 



per horse-power exerted, besides the weight of the apparatus. 



Now, we shall find later (see p. 871) that no birds support even half that 

 weight per horse-power which they have the power to exert, and that recent aero- 

 plane experiments prove its impossibility. On the ground, therefore, that he is 

 too heavy in proportion to his strength, it is clear that man is unfitted for flight, 

 as well as because his limbs are not adapted for it. 



It does not follow, however, that by aid of mechanisms apart from his own body, 

 and worked by power independent of his own strength, man may not imitate, com- 

 pete with, and even outdo the fowls of the air. 



Let us consider a few facts showing what birds can do, A gannet hovers in 

 the air above the sea. Suddenly he nearly closes his wings, swoops down, and 

 with a splash disappears below the surface. Shortly after he reappears with a 

 fish in his mouth, which he swallows in a few gulps ; then, after swimming on the 

 surface a little, he reascends into the air to repeat the operation. 



The swallow rises into the air with a few rapid movements of the wings, then 

 slides down as though on an aerial switchback, and then up again till he nearly 

 reaches his original height, or he circles round by raising one wing, like a runner 

 rounding a curve. 



> Rules, Tables, and Data, pp. 719 and 720, by D. K. Clark. 

 ^ Animal Mechanics, by Dr. Haughton. 



