On %e Tlieorif of Mixed Gases. 513 



dry air. With a view to find whether this He 

 the case or not, T filled a^bottle-with running 

 water ofthe temperature of 59 degrees, which, 

 when carefully poured out again, weighed 

 7794 grains. The bottle, having a dew left 

 sticking to the sides of it, was placed in water 

 at the temperature of 126 degrees: the mouth, 

 which remained about an inch above the 

 surface, was covered with my hand, care being 

 taken to remove it frequently for an instant to 

 permit the vapour and expanding air to escape. 

 After keeping it in this situation about two 

 minutes, I secured the mouth in the manner 

 described above and inverted it in a quantity ot 

 the same water, where it was reduced to 59 

 degrees ; in consequence of which it took up 

 1622 grains of water, leaving a space equiva- 

 lent to 6172 grains. If the experiment be 

 now inverted, 6172 parts of air will occupy 

 the space of 7794 such parts when its tem- 

 perature is raised from 59 to 126 degrees; 

 which is nearly double the expansion of dry 

 air in like circumstances. For according to 

 Mr. Schmidt's experiments, 1000 parts of dry 

 air of 59 degrees will become equal to 1133,03 

 such parts, by being heated to 126 degrees; 

 therefore, by the rule of proportion, if 1000 

 parts give an expansion of 1133,03 such parts, 

 6172 parts give only 820 : but the difference 



