e of Count Rumford. 465 



the particles of liquids as they are heated or cooled. He 

 demonstrated that heat cannot be propagated down- 

 wards in liquids as long as they continue to be con- 

 densed by cold, "that ice would take more than 

 eighty times as long to melt when boiling water stood 

 on its surface as it would take if allowed to swim 

 on the top of the hot water ; and that water at the 

 temperature of 41 would melt even more ice, when 

 standing on its surface, than boiling water." The 

 proof was thus complete that water is almost a perfect 

 non-conductor of heat. The experiments with these 

 results were chiefly made in March, 1797. The Count 

 adds to his conclusion, at this point, the following ob- 

 servation : 



" The insight which this discovery gives us in regard to the 

 nature of the mechanical process which takes place in chemi- 

 cal solutions is too evident to require illustration ; and it 

 appears to me that it will enable us to account in a satisfac- 

 tory manner for all the various phenomena of chemical affini- 

 ties and vegetation. Perhaps all the motions among inanimate 

 bodies on the surface of the globe may be traced to the same 

 cause, namely, to the non-conducting power of Fluids, with 

 regard to Heat." 



Pursuing his investigations, the Count recognizes the 

 fact that as the motions in a liquid, when undergoing a 

 change of temperature, are caused by a change in the 

 specific gravity of those particles of the liquid which 

 become either hotter or colder than the rest of the mass, 

 there will be a difference in the conducting power of the 

 liquids, according as their respective specific gravities are 

 more or less changed by any given change of tempera- 

 ture. The less, then, that the specific gravity of a liquid 

 is changed by any given change of temperature, the 

 30 



