RADIATION 67 



these liquids, at a common thickness, to intercept the 

 waves of heat, was carefully determined. The vapors of 

 the liquids were next taken, in quantities proportional to 

 the quantities of liquid, and the power of the vapors to in- 

 tercept the waves of heat was also determined. Commenc- 

 ing with the substance which exerted the least absorptive 

 power, and proceeding onward to the most energetic, the 

 following order of absorption was observed: 



Liquids Vapors 



Bisulphide of carbon. Bisulphide of carbon. 



Chloroform. Chloroform. 



Iodide of methyl Iodide of methyl 



Iodide of ethyl Iodide of ethyl 



Benzol. Benzol. 



Amylene. Amylene. 



Sulphuric ether. Sulphuric ether. 



Acetic ether. Acetic ether. 



Formic ether. Formic ether. 



Alcohol Alcohol 

 Water. 



We here find the order of absorption in both cases to 

 be the same. We have liberated the molecules from the 

 bonds which trammel them more or less in a liquid con- 

 dition; but this change in their state of aggregation does 

 not change their relative powers of absorption. Nothing 

 could more clearly prove that the act of absorption de- 

 pends upon the individual molecule, which equally asserts 

 its power in the liquid and the gaseous state. We may 

 safely conclude from the above table that the position of 

 a vapor is determined by that of its liquid. Now, at the 

 very foot of the list of liquids stands water, signalizing it- 

 self above all others by its enormous power of absorption. 

 And from this fact, even if no direct experiment on the 

 vapor of water had ever been made, we should be entitled 



