INTRODUCTION. 



3 



attending its realization) might well be regarded an impossi- 

 bility. As, however, the flying creatures are legion, both as 

 regards number, size, and pattern, and as the bodies of all are 

 not only manifestly heavier than the air, but are composed 

 of hard and soft parts, similar in all respects to those com- 

 posing the bodies of the other members of the animal kingdom, 

 we are challenged to imitate the movements of the insect, bat, 

 and bird in the air, as we have already imitated the move- 

 ments of the quadruped on the land and the fish in the water. 

 We have made two successful steps, and have only to make 

 a third to complete that wonderfully perfect and very com- 

 prehensive system of locomotion which we behold in nature. 

 Until this third step is taken, our artificial appliances for 

 transit can only be considered imperfect and partial. Those 

 authors who regard artificial flight as impracticable sagely 

 remark that the land supports fhe quadruped and the water the 

 fish. This is quite true, but it is equally true that the air sup- 

 ports the bird, and that the evolutions of the bird on the wing 

 are quite as safe and infinitely more rapid and beautiful than the 

 movements of either the quadruped on the land or the fish in 

 the water. What, in fact, secures the position of the quadruped 

 on the land, the fish in the water, and the bird in the air, is 

 the life ; and by this I mean that prime moving or self-govern- 

 ing power which co-ordinates the movements of the travelling 

 surfaces (whether feet, fins, or wings) of all animals, and adapts 

 them to the medium on which they are destined to operate, 

 whether this be the comparatively unyielding earth, the mobile 

 water, or the still more mobile air. Take away this life suddenly 

 — the quadruped falls downwards, the fish (if it be not speci- 

 ally provided with a swimming bladder) sinks, and the bird 

 gravitates of necessity. There is a sudden subsiding and ces- 

 sation of motion in either case, but the quadruped and fish have 

 no advantage over the bird in this respect. The savans who 

 oppose this view exclaim not unnaturally that there is no 

 great difficulty in propelling a machine either along the land 

 or the water, seeing that both these media support it. There 

 is, I admit, no great difficulty now, but there were apparently 

 insuperable difficulties before the locomotive and steam-boat 

 were ir vented. Weight, moreover, instead of being a barrier to 



