426 MODERN CHEMISTRY. 



occurred ; and their intimate relation to the state and pro- 

 gress collaterally of the other physical sciences. They are 

 revolutions depending not solely on the accession of new 

 facts, but involving also new principles and methods of re- 

 search ; a larger scope and more profound objects of enquiry, 

 and modes of experiment infinitely more subtle and exact 

 wherewith to attain them; and with all this, an altered 

 nomenclature and new symbolical language, needful to meet 

 the exigencies thus created. A chemist of forty years ago, 

 well versed in the subject as it then stood, would be utterly 

 lost in the labyrinth of new names, new facts, and new com- 

 binations which appear in the works before us. This is true, 

 even as to the elementary parts of the subject, and what is 

 called Inorganic Chemistry : yet more true as regards the 

 wide domain of Organic Chemistry, a land newly opened, 

 rich in products, and cultivated with such zeal and success, 

 that any one stationary in knowledge, even for half the time 

 we have named, would enter it as a stranger to all he saw 

 around. We might give passages without number, taken 

 almost at random from the descriptive parts of organic 

 chemistry, which would come upon the eye of a reader of the 

 old chemical school with the same obscurity as a page of 

 ' Saunders on Uses ' or ' Sugden on Powers ' on the mind of 

 the youthful student of law first opening these mystical 

 volumes.* 



In attestation of the same fact we find that the chemical 

 writings of greatest reputation thirty years ago the original 

 works of Fourcroy, Berthollet, Thomson, Murray, Henry, 

 &c. are now utterly out of date and useless. Even those 

 which replace them to the modern student have their value 



* Pentetkyline-tetrathylated-tetrammonium; Dibromide of Ethylcne-dicthyl- 

 diammonium, are names before me at this moment in a recent paper by Dr. 

 Hofmann presented to the Royal Society. 



It will be seen that each of these names is in effect an analytical description 

 of the compound body under observation. 



