162 



MECHANICS 



Weight 

 (in grams) 



Name of object 



Aluminum 



Bone _... 



Brass . 



Cork 



Glass 4 m 



Iron 



Lead 



Pine __... 



Stone _.. 



Zinc .. 



Volume Density 



(in cubic (grams 



centimeters) per c. c,) 



? 2,6 



? 1.9 



? 8.4 



? .24 



? 2.5 



? 7.7 

 11.3 



? .55 



? 2.6 



? 7. 



62. Drawings, 



In all science work it is very desirable to illustrate 

 the experiments, which you write up r by means of draw- 

 ings. Drawing is like writing, since we use both to 

 express on paper the ideas which we wish to keep in 

 good form, but drawing is often a better means of expres- 

 sion than writing as it sometimes is impossible to write,, 

 or even explain by speecn, some idea which we have. 

 There are two kinds of drawing; that made without 

 instruments called freehand drawing, and that made with 

 instruments called mechanical drawing. In science work 

 mechanical drawing is used more than freehand drawing, 



