MEASUREMENT OF QUANTITY OF MATTER 



17 



By reference to a table of the densities of water at different 

 temperatures, we find the volume of water corresponding to 

 the quantity of matter apparently lost, and this is the same as 

 the volume of the body measured. If the substance to be 

 measured dissolves in water, a liquid which does not dissolve 

 it is used. 



If the body does not sink in water, its density must be ob- 

 tained simultaneously with that of a heavy body, of known 

 density, which will cause it to sink. And a third method is 

 to make such a mixture of two liquids, say alcohol and water, 

 that the body will float in it at any depth. Then find the 

 density of the mixture by direct weighing. This will be the 

 same as that of the body. 



Table of Densities. 



J/ 



= 7 or units of mass in unit volume at C. 



Air . 



Alcohol 



Aluminium 



Brass . 



Copper 



Ether 



Gold . 



Glass 



Glycerin . 



Iron . . . 



Hydrogen . . 



Ice . 



Lead . 



Nitrogen . 



Mercury 



Oxygen 



Platinum . 



Hydrogen sulphate 



Turpentine . 



Sea water . 



Pure water at 4 C. 



Wood. 



0-00129 



0-795 



2-50 to 2-67 



7'80 to 8-54 



8-30 to 8-89 



0-716 

 19-20 to 19-60 



2-50 to 3-50 



1-26 



7-50 to 7-90 



0-0000896 



0-918 to 0-92 

 11-07 to 11-40 



0-001256 

 13-596 



0-00143 

 21-16 to 21-53 



1-854 



0-870 



1-026 



1-000013 



0-4 to 0-9 



