220 Meeting of the British Association, 



as to the multiple relations of these numbers to the equivalent of 

 hydrogen. At the same time, the more recent determinations for 

 the atomic weights of carbon, silver, and some other elements, so 

 closely coincided with this view, that it was very desirable to ex- 

 tend new experiments to the bodies which had fractional atomic 

 weights assigned to them. 



In M. Dumas' Memoirs there are the results, thousrh not the 

 details, of a large series of experiments, on many of the elements. 

 He obtained numbers of precisely the same value as that by the 

 method of the Swedish philosopher — numbers which are not the 

 multiple of the equivalent of hydrogen. But when he pursued 

 his experiments upon these same elements, with the methods of 

 discovery and his own inventiveness, then atomic weights were 

 obtained which corrected themselves from the error inherent in 

 former methods of analysis, and resulted in being multiples of 

 the combining proportions of hydrogen, or in standing in a very 

 simple relation to that number. There is on this point evidence 

 so clear that there is scarcely a chance of deception. The labours 

 of Dumas, Pierre, Peligot, and others, have established the relation 

 by recent determinations of clorine, iodine, bromine, silver, tita- 

 nium. &c. Elements differing so much in chemical character as 

 well as in atomic weight, that it is difficult to conceive any fortui- 

 tous combinations which could have produced such uniformities in 

 the results of analysis. Hence the general view of Prout, that 

 the equivalents of the elements, compared with certain unities, 

 are represented by whole numbers, seems to be established by 

 recent experiment, although it would be premature to declare that 

 there are no exceptions to the law. 



In this country we are familiar with many ingenious discussions 

 on the natural grouping of the elements, and the relations of their 

 equivalent numbers to each other. I allude to the paper of Glad- 

 stone, Odeling, and Mercer, and to the views of Cork, in America. 

 Altho' these efforts point to important dependencies of the elements 

 on each other, yet we cannot adopt them as parts of our scientific 

 system. Another question of a different character, as regards 

 equivalents, has recently received attention. I refer to the pro- 

 posal, to double the equivalents of Carbon and Oxygen, that is to 

 raise them from 6, and 8, to 10, and 16 respectively. As these 

 two elements are essentially connected with the whole system of 

 chemistry, the right determination of their equivalents is a matter 

 of extreme importance. 



