102 ELEMENTARY GENERAL SCIENCE CHAP. 



TABLE OF RELATIVE DENSITIES. 

 Solids and Liquids at 0' C. compared with water at 4" C. 



Rock crystal 2'653 



Solids. 



Platinum (rolled) 22 '069 

 Gold (stamped).. .19-362 



Silver (do.) 10 "474 



Copper (do.) 8*788 



Steel (not ham- 

 mered .. 7-816 



Anthracite T800 



Coal (compact) 1 -329 



Lead (cast) 11-352 Melting ice 



Oak 0-845 



Cork 0-240 



Liquids. 



Mercury 13 '598 



Iron (cast) 7'207 Bromine 2'960 



Heavy spar (ha- Sea-water T026 



rium sulphate) 4-430 . Distilled water (4 : C.)... 1 '000 



Diamond 3 '531 (varies) Olive oil 0'915 



Marble 2 -837 Alcohol (absolute) 0'793 



Relative Density of Gases. The density of a gas is not 

 compared with that of water as a standard, because the number 

 which would be obtained by such a comparison would be so 

 exceedingly small. The standard density adopted is that of the 

 gas hydrogen, which is the lightest form of matter known. The 

 densities of other gases will in every case therefore be greater 

 than unity. To find the density of a gas, all that it is necessary to 

 do is to weigh a flask filled with pure dry hydrogen under certain 

 conditions of temperature and pressure (see Chap. VIII), and then 

 to weigh the same flask filled with the gas of which the density is 

 required under the same conditions of temperature and pressure ; 

 the number of times the gas is heavier than hydrogen is the 

 number representing its density. There are several important 

 precautions which have to be adopted, but for an account of 

 these we must refer the student to works on chemistry. 



RELATIVE DENSITIES OF GASES. 



Hydrogen ... I'O 



Nitrogen 13 '9 



Oxygen 15'9 



Chlorine 35'2 



Ammonia 8'45 



Steam 8'95 



Carbon monoxide 13*90 



Carbon dioxide 21 '85 



