APPENDIX 



559 



The volume of a regular solid, or of a solid geometrical figure, may 

 be calculated from its linear dimensions. Thus, the number of cubic 

 feet in a room or in a rectangular block of marble is 

 found by getting the continued product of its length, 

 its breadth, and its height, all measured in feet. The 

 volume of a cylinder is equal to the product of the #rea 

 of its base (?rr 2 ) and its height, both measured in the 

 same system of units. 



Liquids are measured by means of graduated vessels 

 of metal or of glass. Thus, tin vessels holding a gal- 

 lon, a quart, or a pint are used for measuring gasoline, 

 sirup, etc. Bottles for acids usually hold either a 

 gallon or a half gallon, and milk bottles contain a 

 quart, a pint, or a half pint. Glass cylindrical grad- 

 uates and volumetric flasks are used by pharma- 

 cists, chemists, and physicists to measure liquids. 

 In the metric system these are graduated in cubic VOLUMETRIC 

 centimeters. MASK 



Units of Mass. The unit of mass in the metric system 

 is the kilogram. The United States has two prototype 



kilograms made of 

 platinum-iridium and 

 preserved at the Bureau 

 of Standards in Wash- 

 ington. The gram is 

 one thousandth of the 

 kilogram. The latter 

 was originally designed 

 to represent the mass 

 of a liter of pure water 

 at 4 C. (centigrade 

 scale) . For practical 

 purposes this is the 



STANDARD KILOGRAM kilogram. The gram IS 



