and chiefly on the use of the word Acid. 263 



racy — which, like fossiTs in a rock, tell of the successive changes 

 by which the existing state of things has been brought about. 

 The more strictly technical language, on the other hand, is always 

 formed with more or less premeditation, and is therefore, to a 

 corresponding extent, under control and capable of being re- 

 formed. The existence of such a language and its preservation 

 in the highest possible state of efficiency are of the utmost scien- 

 tific importance ; for, although none but a pedant would in all 

 cases employ it (when the use of more popular expressions could 

 lead to no ambiguity), it is quite certain that accurate language 

 is an essential instrument of accurate thought, and that the 

 progress of any science will be greatly retarded unless its lan- 

 guage is such as to admit of its facts and theories being stated 

 with any required degree of precision. 



These general remarks are meant as answer, by anticipation, to 

 the objection, so often urged to attempted reforms in Chemical 

 Nomenclature, that the proposed modes of expression would be 

 too troublesome for general use. It is contended that this 

 objection, even when real, is by no means necessarily conclusive. 

 A particular innovation might render important services as a 

 part of what has above been called the legal language of the 

 science, although it might never come into general use, from 

 the fact that it corresponded to a degree of precision beyond 

 that required for ordinary purposes. Our aim should be to 

 render our language such that it may be in the power of every 

 chemist to know accurately the ideas which he will convey to 

 the minds of others by his use of it. The extent to which each 

 one avails himself of its resources must, of course, be left to his 

 own discretion. 



At the present time, one of the most important questions 

 which has to be considered, in relation to chemical nomencla- 

 ture, is as to the use of the term Acid. The sense in which 

 this word has been employed of late years has been gradually 

 becoming more uniform than it was previously ; and those che- 

 mists who regard the now prevalent usage as the correct one 

 might well have been content to watch, without attempting to 

 hasten, its still further spread, were it not that a return to a 

 former and, as they consider, improper use of the term has 

 quite recently found an advocate of no less authority than Pro- 

 fessor Williamson, President of the Chemical Society*. 



This distinguished chemist desires to apply the term acid to 

 the class of substances now very frequently called anhydrides or 

 anhydrous acids, and to call, for instance, N 2 5 nitric acid, 

 N 2 3 nitrous acid, (C 2 H 3 0) 2 acetic acid, SO 2 sulphurous 



* "Remarks on Chemical Nomenclature and Notation," by Professor 

 Williamson : Journ. Chem. Soc. vol. xvii. p. 421 (December 1864). 



