Man Not a Fish nor Bird
MARVILLE observes, that Thevenot, author of a curious book, intitled The Art of Swimming, illustrated by figures, maintains throughout this work, that men would swim as naturally as other animals, if it were not that their fear increases their danger. But this does not agree with experience. Let any animal whatever be thrown into a river, shortly after its birth, it will swim; but a child, that is not yet susceptible of fear, undergo the same operation, it will not swim, but sink.
The reason of this he ingeniously conjectures to be, that the human body differs greatly from that of other animals, by its structure and its prefiguration, and what is remarkable by the situation of its centre of gravity. Compared with the other parts of his body, Man has the head very heavy; because it is full of brain, and has much bone and flesh, and no cavities which admit the air; so that the head plunged into water by its own weight, the nostrils and the ears overflow, and the strong parts overcoming the feeble ones, he is soon drowned. Animals, on the contrary, having the head lighter in proportion to the rest of the body, because they have rarely any brain, and that there are chasms in the head, they are enabled to hold the nostrils in the air, and breathing without difficulty, they do not drown as man does, by statical reasons which are undeniable.
In fact the art of swimming, which is acquired by exercise principally consists in holding up the head above the water, that the mouth and nostrils being free, the swimmer breathes with ease; for as to the feet and hands, it is sufficient to move them, and to employ them as oars to conduct the vessel.
Why man can never fly as a bird, even by artificial means, which has been so frequently and so vainly attempted, the following passage offers a satisfactory reason. It does at the same time great honour to its noble, author, the Duke of Newcastle, whom we have had already occasion to notice. I transcribe it from his memoirs.
“When my lord was at Paris, in his exile, it happened one time, that he discoursing with one of his friends, amongst whom was that learned philosopher Hobbes, they began, amongst the rest, to argue upon this subject; namely, Whether it were possible to make man by art to fly as birds do. And when some of the company had delivered their opinion, viz. that they thought it probable to be done by the help of artificial wings; my Lord declared, that he deemed it altogether impossible, and demonstrated it by this following reason: Man’s arms, said he, are not set on his shoulders in the same manner as birds wings are; for that part of the arm which joins to the shoulder is in man placed inward, as towards the breast, but in birds outward, as toward the back; which difference and contrary position or shape, hinders that man cannot have the same flying action with his arms, as birds have with their wings: This argument Mr. Hobbes liked so well, that he was pleased to make use of it in one of his books, called Leviathan, if I remember well.”