'292 HISTORY OF CHEMISTRY. 



tion, whom we have to pursue : and it is only in proportion as wo 

 ourselves overtake those figures in the race, and pass beyond them, 

 that we are enabled to look back upon their faces ; to discern their 

 real aspects, and to catch the true character of their countenan- 

 ces. Except, therefore, I were of opinion that the great truths which 

 Davy brought into sight have been firmly established and clearly 

 developed by Faraday, I could not pretend to give the history of this 

 striking portion of science. But I trust, by the view I have to offer 

 of these beautiful trains of research and their result, to justify the 

 assumption on which I thus proceed. 



I must, however, state, as a further appeal to the reader's indulgence, 

 that, even if the great principles of electro-chemistry have now been 

 brought out in their due form and extent, the discovery is but a very 

 few years, I might rather say a few months, old , and that this novelty 

 adds materially to the difficulty of estimating previous attempts from 

 the point of view to which we are thus led. It is only slowly and 

 by degrees that the mind becomes sufficiently imbued with those new 

 truths, of which the office is, to change the face of a science. We 

 have to consider familiar appearances under a new aspect; to refer 

 old facts to new principles ; and it is not till after some time, that the 

 struggle and hesitation which this employment occasions, subsides into 

 a tranquil equilibrium. In the newly acquired provinces of man's 

 intellectual empire, the din and confusion of conquest pass only gradu- 

 ally into quiet and security. We have seen, in the history of all 

 capital discoveries, how hardly they have made their way, even among 

 the most intelligent and candid philosophers of the antecedent schools : 

 we must, therefore, not expect that the metamorphosis of the theoreti- 

 cal views of chemistry which is now going on, will be effected without 

 some trouble and delay. 



I shall endeavor to diminish the difficulties of my undertaking, by 

 presenting the earlier investigations in the department of which I have 

 now to speak, as much as possible according to the most deliberate 

 view taken of them by the great discoverers themselves, Davy and 

 Faraday ; since these philosophers are they who have taught us the 

 true import of such investigations. 



There is a further difficulty in my task, to which I might refer ; 

 the difficulty of speaking, without error and without offence, of men 

 now alive, or who were lately members of social circles which exist 

 still around us. But the scientific history in which such persons play 

 A part, is so important to my purpose, that I do not hesitate to incur 



