THE 



PHILOSOPHICAL MAGAZINE 



AND 



ANNALS OF PHILOSOPHY. 



[NEW SERIES.] 

 SEPTEMBER 1830. 



XXV. Table of the Atomic Weights of Simple Bodies, accord- 

 ing to Thomson and Berzelius, with a mean Weight deduced, 

 for each Substance. By Mr. John Pride aux. 



To the Editors of the Philosophical Magazine and Annals. 

 Gentlemen, 

 r T , HE well-earned high reputation of Dr. Thomson, who 

 • has, perhaps, done more for the diffusion of the science 

 than any contemporary chemist ; the simplicity of the experi- 

 ments on which his "First Principles" were founded; and 

 the mathematical precision of his results; — gave a general cur- 

 rency to his numbers, the more highly appreciated from their 

 conciseness and facility. And it is proportionately disappoint- 

 ing, when habituated to their convenient application, to ob- 

 serve, that, of several of those experiments which have been 

 disputed, hardly one, in other hands, has exactly corresponded 

 to his results. 



If thus obliged, for the present, to defer our expectation of 

 precise knowledge of the relative atomic weights, we are, 

 however, not required to undervalue the importance of Dr. 

 Thomson's investigations. It is a practice, in atomic inquiries, 

 to obtain approximations by different modes of operation, and 

 take a mean number, subject to such corrections as may seem 

 requisite. 



We have now two general tables of atomic weights, ob- 

 tained by different experimental methods, and on the au- 

 thority of men of the first eminence in the science of Chemistry. 

 Although considerably at variance, yet each is so near the 

 truth as to have been adopted by a great body of the most 

 competent judges ; the numbers of Berzelius being generally 

 used on the continent of Europe, and those of Thomson in 

 Britain and America. Is it not probable, until more defini- 



N. S. Vol. 8. No. 45. Sept. 1830. Y tive 



