FL YING-MA CHINES. 1 1 



around in circles, occasionally elevating themselves by a few flaps of 

 the wings, they glide down and up the aerial inclines without appar- 

 ently any effort whatever. But a close observation will show that at 

 every turn the angle of inclination of the Aviugs is changed to meet 

 the new conditions. There is continual movement with power — by the 

 bird it is done instinctively, by our machine only through mechanism 

 obeying a mind not nearly so well instructed. 



The study of the flight of birds and insects has of late years re- 

 ceived a great deal of attention, and, in a general way, the motions of 

 the wings are fairly well understood. We could probably very closely 

 imitate these motions, but the question at once arises, in doing so, 

 would we be applying our power in the most effective way ? While 

 somewhat similar, the movement and construction of the wings of 

 flying creatures vary considerably. What is best for a heavy body 

 with short wings is by no means best for a light body with long 

 wings ; nor does a sea-bii'd, constantly on the wing, but perhaps 

 not a rapid flier, fly in the same way as a pigeon or humming-bird ; 

 and, in any particular case, it does not necessarily follow that Na- 

 ture has provided the most efficient apparatus ; or, in other words, 

 that the power the bird possesses could not be utilized more effect- 

 ively. Nature can not always be trusted. We can study and under- 

 stand her laws, but she does not pretend to apply them on economical 

 principles. Fish and marine animals swim in a great variety of ways, 

 they have all sorts of propelling arrangements, but there can be no 

 doubt that a screw-propeller is vastly more efficient than any of them ; 

 and why should we try to copy the motions of a bird's wing any more 

 than those of a fish's tail ? The motions are very complicated in any 

 case, and our machine, imitating them, would be complex and liable 

 to get out of order. And one can not help thinking that we are about 

 as likely to make a steam road-wagon by imitating the action of a 

 horse, as we are to make a practicable flying-machine by copying the 

 motions of a bird. The desired results can probably be obtained in a 

 much more simple and effective way. 



Still, the study of flying creatures has brought out many interest- 

 ing and suggestive facts, and has given us, too, some encouragement. 



In the first place, we notice that all birds are heavy, and that the 

 expanse of wing generally diminishes in proportion to the increase of 

 weight. The following is a table prepared by M. Lucy, showing this 

 very clearly : 



Table giving the Expanse of Wing- Surface for each Pound of Weight. 



Square feet. 



Gnat 48-9 



Dragon-fly 21-65 



Cockchafer 5'1 



Sparrow 27 



Pigeon 1-2 



Vulture 0-82 



Australian crane 041 



