16 



FARADAY 



of gravity is at the lowest point when the image is standing 

 upright; and we may be certain, when I am tilting it over 



FIG. 5 



FIG. 6 



(see FIG. 6), that I am lifting up the centre of gravity (a), 

 and raising it from the earth. All this is effected by put- 

 ting a piece of lead inside the lower part of the image, 

 and making the base of large curvature, and there you have 

 the whole secret. But what will happen if I try to make the 



figure stand upon a sharp 

 point? You observe I must 

 get that point exactly under 

 the centre of gravity, or it 

 will fall over thus [endeavor- 

 ing unsuccessfully to balance 

 it] ; and this, you see, is a dif- 

 ficult matter; I can not make 

 it stand steadily; but if I em- 

 barrass this poor old lady with 

 a world of trouble, and hang 

 this wire with bullets at each 

 end about her neck, it is very 

 evident that, owing to there 

 being those balls of lead hang- 

 ing down on either side, in 

 addition to the lead inside, I 

 have lowered the centre of 



gravity, and now she will stand upon this point (Fie. 7), 

 and, what is more, she proves the truth of our philosophy by 

 standing sideways. 

 I remember an experiment which puzzled me very much 



