420 CHAPTER Ol<' VARIETIES. 



that appear sufficient to render a fall fatal. Now the operations of 

 instinct, though in many points of view not a little miraculous, are 

 always regulated by some ingenious principle, when that can be dis- 

 covered ; and in the instance of the cat always falling on her feet, it 

 appears to me that the same principle operates which enables listowalk 

 upright by regulating our centre of pressure according to the things 

 around us. In learning to walk, we judge of the distances of the ob- 

 jects which we approach by the eye ; and by observing their perpen- 

 dicularity determine our own. Hence it is that no one who is hood- 

 winked can walk in a straight line for a hundred steps together ; and 

 for the same reason most people become dizzy when they look from the 

 summit of a tower or battlement much raised above the objects in the 

 sphere of distinct vision. A whirling wheel or the current of a rapid 

 river, or the apparent motion of the sea on looking over the side of a fast 

 sailing ship, have often a similar effect. When a child can first stand 

 erect on his legs, if you gain his attention to a white handkerchief 

 tended like a sail, he will stand firm, but the instant you wave it he will 

 tumble down. It is for this reason that rope-dancers, who have a very 

 narrow base upon which to maintain the line of direction perpendicular, 

 keep their eye fixed on a point of the framework upholding the rope 

 by which to regulate their centre of pressure, and for the same reason 

 those who perform difficult feats of balancing keep their eye fixed on 

 the top of the things balanced, to retain the line of direction within the 

 base. It may be accordingly inferred that the reason why a man loses 

 his balance when tipsy is, that his eyes roll so unsteadily as to prevent 

 him from regulating his balance by the things around him, while the 

 muscular feelings that assist him when hoodwinked are also deranged. 



It would be curious to ascertain whether a cat, if rendered tipsy, 

 would fall equally on her feet when dropped from a height as a sober 

 cat. The difficulty of the experiment would lie in getting a cat to 

 drink beer, wine, or spirits, all of which it greatly dislikes. I have no 

 doubt, indeed, that it is by fixing the eye on the things around, that a 

 cat falling from a height regulates her centre of pressure, so as to fall 

 on her feet. She is, however, aided in this by the form of her body, 

 somewhat the reverse of that of a greyhound, the centre of pressure 

 lying far back from the head, and consequently bringing down the hind 

 feet rather before the fore feet. 



* From " ALPHABET OF PHYSICS, or NATURAL PHILOSOPHY," by the Editor, 

 now in the press. 



