y6 Mr. Henry Wilde on the 



are correlated directly with atomic condensations and 

 atomic weights within that space. Hence the law that every 

 increase of atomic weight, in a well-defined odd or even 

 series of elements, is attended by an increase of specific 

 gravity is a natural consequence of the theory. This law 

 is well seen in my complete Table of the elements, in which 

 are inserted the specific gravities below the numbers 

 expressing the atomic weights. 



In considering the experimental atomic weights of the 

 series Yin and H2K, one cannot but be struck with the 

 admirable degree of precision with which these constants 

 of nature have been determined ; but the microscopic habit 

 of mind, induced by this extreme precision, in weighing 

 and measuring, constitutes a real danger to the progress of 

 chemical philosophy, and, unless guarded against, may ren- 

 der a good chemist as incapable of taking broad views of 

 his own science, as a cretin in the depths of an Alpine 

 valley would be in forming a just conception of the figure 

 of the earth. 



Dalton's fundamental law of chemical combination in 

 definite and multiple proportions — first announced to the 

 world through this Society* — was founded on approxima- 

 tions differing for the principal elements more than thirty 

 per cent, from later determinations^ and through the 

 doubling of many of the old atomic weights, the differences 

 from the original determinations have largely increased. 



The law of the multiple proportions of the atomic 

 weights of the elements, in whole numbers of hydrogen, is 

 the natural development of the law of chemical combination 

 in multiple proportions, and just as spectral analysis has 

 established the continuity of the phenomena of terrestrial 

 and cosmical chemistry, so this continuity is further mani- 

 fested by the mathematical relations which have been 



* Memoirs of the Literary and Philosophical Society of Manchester, Vol. I. 



[2 series], pp. 250-281. 

 +Dalton's New System of Chemical Philosophy, Vol. II., p. 352, 1827. 



