VOLUMES OF SOLIDS. 



5 



frequent use in physical works, and is written briefly 

 thus 4 cc.' 



The volume of a rectangular solid like abedefqh 

 (fig. 4) 1 is easily ascertained; for we may suppose the 

 solid to be cut into flat plates each one unit in thickness ; 

 each of these plates, as ik Imefg A, may be divided 

 into cubic centimetres, and we shall obtain 20 CC from a 

 plate 5 cm in length and 4 cm in breadth; and the number 

 of such plates will be equal to the number of linear units 

 in the thickness of the body. In the present case there 

 are three such plates, each of 20 CC . The entire volume of 

 the body is, therefore, 3x4x5 = 60 CC . The volume 

 of a rectangular solid is thus the product. of its length, 



1 Many figures in the text, intended to show all three dimensions of 

 the objects represented, are drawn in what is called anisometric parallel 

 projection; such figures are marked l an. proj? The scale on which the 



r 



FIG. 5 (an. proj. real size). 



figures marked ' real size ' are drawn will become clear from fig. 5. All 

 dimensions in height, o Y, are represented in their real magnitude ; the 

 dimensions from left to right o x, are ^th j those from the front to the back 

 of the figure o z, are \ of the true magnitude. 



