Michael Faraday, his Life and Works. 155 
action of magnetism and dynamic electricity upon light and 
upon natural bodies in general. It is true that there are some 
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that is to say, they are the fruit of some particular circumstances 
substances carried up by vapor—experiments undertaken in 
consequence of the invention of Armstrong’s machine. Lastly, 
there are others which only contain the more or less indirect con- 
sequences of the fundamental discoveries, which will be ex- 
plained in one of the three subdivisions under which we have 
the study of electrochemistry. It was, moreover, to ; ¢ 
trochemistry that his attention must have been first directed in 
many oxyds, some chlorids and iodids, and a multitude of salts, 
which do not conduct electricity in the solid state, but, without 
any intermixture of water, become excellent conductors when 
liquefied by heat, and are not eee by electricity with 
Separation of their elements in the same way as aqueous solu- 
tions. To the list of these compounds Faraday adds that of 
