42 WELLS'S NATURAL rHILOSOPHT. 



"White pino 0.420 



Alcohol 0.800 



Ether 0.720 



Cork 0.240 



GASES. 



Pure, dry atmospheric air 1.000 



Carbonic acid gaa 1.520 



Oxygen 1.100 



Nitrogen 0.970 



Ammoniacal gas 0.580 



Hydrogen 0.070 



How can we ^^' "^ ^"^^'^ ^°°* °^ 'water weighs almost exactly 1,000 

 determine the ounces avoirdupois, or 62^ pounds. If^ therefore, the specific 

 of™'bod7fi-om S^^'^'^'^y of water be represented by the number 1,000, the 

 its Specific numbers which express the specific gravity of all other solids 



ravi y ^^^ liquids, will also express the number of ounces contained 



in a cubic foot of their dimensions. Thus, the specific gravity of gold being 

 19.360, it follows that a cubic foot of gold will weigh 19,360 ounces; and the 

 specific gravity of cork being 0.240, the weight of a cubic foot of cork will 

 bo 240 ounces. By means of a table of specific gravities, therefore, the 

 weight of any mass of matter can be ascertained, provided we know its cu- 

 bical contents, by the following rule : 



83. Multiply the weight of a cubic foot of water by 

 t^e specific gravity of a substance ; the product will be 

 the weight of a cubic foot of that substance. 



Thus, anthracite coal has a specific gravity of 1.800. This, multiplied by 

 the weight of a cubic foot of water, 1,000 ounces, gives 1,800 ounces, which 

 is the weight of a cubic foot of coal. 



How can we 84. Thc volume, or bulk, of any givcH Weight 

 bink o^f "a Bu^b- ^^ ^ substance can also be readily calculated, 

 spTcific'^Grav! ^Y dividing the number expressing the weight 

 "^' in ounces by the number expressing the spe- 



cific gravity of the substance, omitting the decimal points; 

 the quotient will express the number of cubic feet la the 

 volume, or bulk. 



Thus, for example, if it be desired to ascertain the bulk of a ton of iron, It 

 is onlj necessary to reduce the ton weight to ounces, and divide the number 

 of ounces by 7.800, the specific gravity of iron ; the quotient will be the 



.,,.. ,. , number of cubic feet in the ton weicrht. 

 If ths particles t^ i • i n it 



of matter were 85. If the particles 01 all matter were per- 



iree io move, ni/> iii» 



how would lectly tree to move among themselves, their 

 th^-Vver?^^ arrangement in space would always be in ex- 



