SPECIFIC GRAVITY, OR WEIGHT. 41 



of "weiglit in water ; the quotient will give the specific 

 gravity of the liquid. ' 



Thus a solid hodj (a piece of glass is generally used) loses 20 grains when 

 •weighed in water, and 30 grains when weighed in acid; 30-i-20 = 1.5, the spe- 

 cific gravity of the acid. 



79. There are various other methods of obtaining the specific gravity of 

 solids and liquids.* Those we have described are the ones most generally 

 adopted. 



Bpwdoweob- 80. For obtaining the specific gravity of 

 ^ *G^rav?b7" gases, air instead of water is adopted as the 

 •fa Gas? standard of comparison. The weight of a 



given volurae or measure of a gas is compared with the 

 weight of an equal volume of pure atmospheric air, and 

 the weight of the gas divided by the weight of the air, 

 will express the specific gravity of the gas. 



81. The following table exhibits the specific gravity of various solid, liquid, 

 and gaseous bodies ; pure water, having a temperature of 60 degrees Fahren- 

 heit's thermometer, being assumed as the standard of comparison for sohds 

 and hquids, and pure, dry air, having the same temperature, being assumed 

 as the standard of comparison for gases. The metal platinum has the greatest 

 specific gravity of any sohd body, being 21.50 times heavier than an equal 

 bulk of water ; and hydrogen gas the least specific gravity of any of the gases, 

 being 14.4 lighter than an equal bulk of air, and 12.000 lighter thanan equal 

 bulk of water. The.se two substances are respectively the heaviest and light- 

 est forms of matter with which we are acquainted. 



SOLIDS AKD LIQUIDS. 



Distilled water 1.000 



Platinum • 21.500 



Gold 19.360 



Mercury 13.600 



Lead 11.450 



Silver 10.500 



Copper 8.870 



Iron 7.800 



Flint Glass 3.320 



Marble 2.830 



Anthracite coal 1.800 



Box-wood 1.320 



Sea-water 1.020 



Whale oil 0.920 



Pitch-pine wood 0.060 



• See Hydrometer. 



