368 CALORIFICATSON. 



of the solar rays, not only preserves its gaseous 

 form, near the surface of the earth, but at the 

 highest point of elevation, and at all degrees of 

 temperature, whether high or low. It is this pro- 

 perty which particularly distinguishes gas from 

 vapor ; vapor by the reduction of temperature, 

 loses all the properties which it had obtained, 

 and returns to its liquid state; gas, on the 

 contrary, not only preserves its gaseous state 

 at all degrees of temperature, but of external 

 pressure also; while a cold decanter, intro- 

 duced into a hot room, will separate the water 

 from the gas/and collect it on its whole surface: 

 gas will not only remain unaltered by time, 

 but preserve its gaseous form under unequal 

 degrees of temperature, for an indefinite period. 

 The difference which exists in the property 

 of gas and vapor, clearly proves the difference 

 which exists in the nature of the agent, by 

 which the conversion of water into vapor, and 

 gas, had been accomplished : it manifests that 

 the power of the solar rays far exceeds the power 

 of caloric, or fire. Although the dilatation be 

 very considerable, which water undergoes when 

 it is converting from a liquid to a vaporific 

 state, it, nevertheless, bears no proportion % to 

 its power of dilatation after it is actually 

 formed into vapor. From Mr. D ALTON'S 

 experiments it appears, that however different 

 the chemical properties of different gases may 



