114 Review of Dr. Thomson 



of M. Gay Lussac and Dr. Wollaston ; and the individual, who 

 should collect and arrange these into a compendious volume, 

 would do no mean service to science. Of such philosophical 

 principles we can perceive no trace in Dr. Thomson's book ; 

 though the modern multiplication of chemical objects, simple and 

 compound, loudly demands their general connexions and depen- 

 dencies to be developed. 



" An Attempt to establish the First Principles of Chemistry by 

 Experiment," is the title of Dr. Thomson's book; a title which 

 may be understood in two senses. First, it may seem to imply 

 that the doctor modestly offers his labours as a mere attempt ; or 

 secondly, that others before him might perchance have laid down 

 first principles of chemistry, but that the grand sera of esta- 

 blishing them by experiment, was reserved for himself. The reader 

 is not left long in suspense by the ambiguity of the title ; for the 

 first pages show that the latter conceit has taken possession of 

 the author's mind. From the preface, indeed, one might be led to 

 look for some of those Herculean achievements with which Sir 

 H. Davy astonished the world in his Elements of Chemistry, 

 although his title-page did not blazon them forth. But nulla fides 

 fronti is an adage which the reviewer has too many reasons to 

 recollect. 



We shall not, however, deal ungenerously with the Doctor ; far 

 less mete out to him with his own measure. We are ready to ad- 

 mit that by noting the mutually precipitating quantities of two 

 neutral salts, he has in several cases given useful corrections of 

 the primitive combining weights of bodies ; and that he has, on 

 some occasions, shewn errors in the second, and even first, decimal 

 places of numbers formerly found. But, undoubtedly, his chief 

 ingenuity is displayed in concealing, throughout the details of the 

 book, the previous researches on the same topics of other experi- 

 menters, even when their results do not perceptibly differ from 

 his own, which he presents as absolute perfection. Hence a young- 

 student will be led by the perusal of Dr. Thomson's " Attempt," 

 to consider it both as the commencement and completion of che- 

 mistry, since he deigns to notice few precursors, and those chiefly 

 for the purpose of pointing out their mistakes. He demonstrates 

 his own numbers to be true, frequently to a millionth part ; and 

 rarely rests satisfied with a possible error of one part in a 

 thousand ! 



Nothing places in so strong a light the vast improvement of 

 practical chemistry during the last thirty-five years, as a compa- 

 rison of modern results on chemical equivalents, with those ob- 

 tained by Richter in his Researches published in 1792, and some 

 succeeding years. He mixed together two neutro-saline solutions, 

 in such a proportion, as to produce their mutual decomposition, as 

 indicated by the complete precipitation of the new-created com- 



