s 
172 Prof. A. de la Rive’s Memoir of 
distinction so generally accepted between vapors and permanent 
gases. 
tablishes between chemical affinity and the production.of elec- 
the eae of electrical phenomena. By his experiments 
on. t. 
to construct. 
I designedly say, which we are endeavoring to construct ; for 
we must carefully avoid thinking that it is already construc” 
ted. Since the fine discovery of the mechanical equivalent of 
