the Diffusion of Gases. 247 







gen, the square-root is 1.3456, and the reciprocal of the square- 

 root 0.7432. 



Hence, 1 cyanogen is replaced 1.3456 air; and 

 1 air replaces . . 0.7432 cyanogen. 



1st, 83 cyanogen were replaced by 99 air ; 2c^ 75 cyanogen 

 by 90 air ; 3d, 50 cyanogen by 63 air. The last experiment is 

 the most favourable. But 100 cyanogen are replaced, according 

 to that experiment, by 126 air only, instead of 134. This devia- 

 tion from the law, depends on the property of the plaster-plug, 

 which it shares with all porous bodies, to absorb and condense a 

 portion of all those gases which, like cyanogen, are easily lique- 

 fied. It is evident, that if a portion of the cyanogen is with- 

 drawn in this way, a certain contraction is occasioned, and again 

 really less of the gas is submitted to diffusion, and from both 

 causes, the expansion is less than it ought to be. It is possible, 

 also, that the cyanogen may have contained a little nitrogen. 



7. Muriatic Acid Gas. Specific gravity 1.28472 ; square root, 

 1.1334 ; reciprocal of square root 0.8823. Hence, 



1 muriatic acid should be replaced by 1.2847 air; and 



1 air should replace 0.8823 muriatic acid. 



In the case of this gas, the expansion from diffusion was over- 

 powered by the absorbent property of the plug. 



94 measures contracted to 88 in ten minutes, and remained at 

 that quantity for nine minutes, and then expanded to 90 mea- 

 sures in twenty-five minutes more. The plug, upon a subse- 

 quent examination, appeared to be injured, and rendered too 

 permeable, by a chemical action of the muriatic acid upon the 

 hydrated sulphate of lime. 



8. Ammoniacal Gas. Density 0.5902. Square root 0.76825 ; 

 reciprocal of square root 1.3016. Hence, 



1 ammoniacal gas should be replaced by 0.76825 air ; and 

 1 air should replace 1.3016 ammoniacal gas. 



i i 2 



