ADVERTISEMENT. 



THE rapid progress of modern invention and dis- 

 covery, involving the continual increase of discrimina- 

 tive nomenclature, has long made it evident that no 

 absolutely complete Dictionary of Technical Terms 

 can ever he compiled. Yet there are some, even among 

 the critical, who look upon every such work as the pre- 

 sent with undue expectation, and do not hesitate to 

 find fault because impossibilities are not achieved. It 

 is necessary, therefore, to explain that an exhaustive 

 dictionary of Chemistry alone, up to the existing stage 

 of that science, would fill several volumes larger than 

 the present, and be, from the necessary cost, almost 

 inaccessible to either the general or the special student. 

 AVith the terminology of all the other sciences added, 

 it is plain that a work would be involved of such 

 dimensions that a remunerative cimilation could 

 hardly be expected. 



Still, however, a Scientific Dictionary, accurate in 

 its definitions, and something much more than merely 

 general in its scope and details, was seriously wanted 

 when the first edition of the present work appeared ; 

 and Mr. Buchanan, in his " Technological Dictionary," 

 A 2 



