CENTRE OF GRAVITY. 



21 



will know at once that it is the centre of 

 gravity that point in me where the whole 

 gravitating force of my body is centred, and 

 which I thus bring in a line over my foot. 



Here is a toy I happened to see the other 

 day, which will, I think, serve to illustrate our 

 subject very well. That toy ought to lie some- 

 thing in this manner (fig. 5). And would do 

 so if it were uniform in substance; but you 

 see it does not, it will get up again. And now 

 philosophy comes to our aid; and I am per- 



Fig. 5. 



Fig. 6. 



fectly sure, without looking inside the figure, 

 that there is some arrangement by which the 

 centre of gravity is at the lowest point when 

 the image is standing upright; and we may be 

 certain when I am tilting it over (see fig. 6) 

 that I am lifting up the centre of gravity (a), and 

 c 3 



