64 OXYGEN AND HYDROGEN GASES. 



temperature of 48 b . Had it been dry, its volume 

 would have been only 135-4*755 cubic inches.* 

 At the temperature of 60, 135-4755 cubic 

 inches of gas become 138-7551 cubic inches.t 



Thus it appears, that when 100 grains of zinc 

 are dissolved i dilute sulphuric acid, the hydro- 

 gen gas evolved, supposing it perfectly dry, and 

 supposing the barometer to stand at 30 inches, 

 and the thermometer at 60, amounts to 

 138*7551 cubic inches. Now, it has been de- 

 monstrated long ago, by Lavoisier, that the hy- 

 drogen gas thus evolved is derived from the 

 water with which the sulphuric acid is diluted. 

 A portion of this water is decomposed ; its oxy- 

 gen unites to the zinc, and converts it to an 

 oxide, while the hydrogen makes its escape in 

 the state of gas. The other constituent of the 

 water, then, the oxygen has united to the zinc. 



* Let p = pressure of atmosphere = SO inches mercury. 



J'= elasticity of vapour, at 48 = 0-351 inches mercury. 

 x = volume of dry gas at 48. 

 It has been shown by Dal ton, that 

 pae 



P-f 



137-08 /, 137-08 f 

 x = and (substituting for p and f their 



= 137-08. Consequently 



mbstit 

 values, ) 



4064 -265 

 x = 30 = 135-4755 cubic inches. 



f From the experiments of Guy-Lussac we learn, that air and all gases 

 increase in bulk _^_ part for every degree of Fahrenheit's thermometer. 

 Hence at 60, the volume of the gas is 2 greater than at 48. Now, 

 ^ of 135-4755 is 3-2796. Adding this to 135-4755, the volume be- 

 comes 138-7551 cubic inches. 



