Mr. Griffin on the Statical Relations of ^ Gaeea. 66 



To find the Specific Gravity of a gas, — ^ — '- = sp. gr. 



To find the Atomic Weight of a gas, a,w» :=a,m. x f' gr. 



To find the Atomic Measure of a gas, = a, m, 



8p.gr. 



The seventh column of the Table shows the composition in volumes, 

 of a single volume of every different gas. In respect to the elements, 

 it shows also what relation a single volume of each bears to a single 

 atom. Thus, one volume of Oxygen is seen to be equal to one atom ; 

 one volume of Arsenic to be equal to two atoms; one volume of Mer- 

 cury to be equal to half an atom ; and one volume of Sulphur to be 

 equal to three atoms. In respect to the compound gases, it shows the 

 proportions, both of their proximate and ultimate components. Thus, 

 one volume of Hydrocyanic acid is seen to contain, as proximate con- 

 stituents, half a volume of Cyanogen, and half a volume of Hydrogen, 

 while, as ultimate constituents, it contains half a volume of Nitrogen, 

 half a volume of Carbon, and half a volume of Hydrogen. It must 

 be borne in mind, in examining the details of this colunm, that the 

 symbols invariably signify volumes, and not atoms, and that the frac- 

 tions are fractions of volumes and not of atoms. 



FORMULJS FOR DETERMINING THE WEIGHT OF A GIVEN MEASURE 



OF ANY Gas. 



1. In reference to English Cubic Inches. 



Thermometer 60° F. Barometer 30 inches. 



Multiply the specific gravity of the gas, as stated in column fifth of 

 the Table, by its measure, expressed in cubic inches, and the product 

 by 0.003418. The result is the weight of the gas expressed in imperial 

 grains : 



Lot X be the number of cubic inches of gas, then. 



Examples: — 1. The weight of 100 cubic inches of oxygen gas is 

 100.000 X 100 X .003418 = 34.18 grains. 



2. The weight of 50 cubic inches of atmospheric air is 90.695 X 

 50 X .003418 = 15.4998 grains. 



2. In reference to Cubic Centimeters. 



Thennometer 0** Centigrade. Barometer 0.76 meter. 



Multiply the specific gravity of the gas, as given in column fifth of 

 the Table by its measure, expressed in cubic centimeters, and the 

 product by 0.0000143236. The result is the weight of the gas 

 expressed in grammes. 



Absolute weight in grammes of >^ _ .0000143236. 



X cubic centimeters of gas. J i' & ^ ^ 



