202 



ANNUAL OF SCIENTIFIC DISCOVERY. 



action itself. Even should this hope remain unrealized, the field itself is too 

 wide to remain unexplored; and, to say nothing of discovery, the use of 

 photography merely as a chemical test may prove very valuable, as I have 

 myself quite recently experienced, in the evidence it lias afforded me of the 

 presence in certain solutions of a peculiar metal having many of the charac- 

 ters of arsenic, but differing from it in others, and strikingly contrasted with 

 it in its powerful photographic qualities, which arc of singular intensity, sur- 

 passing iodine, and almost equalling bromine. There is another class of 

 phenomena which, though usually considered as belonging peculiarly to the 

 domain of general physics, and so out of our department, seems to me to 

 want some attention in a chemical point of view. It is that of capillary 

 attraction. The coefficient of capillarity differs very remarkably in different 

 liquids, and no doubt also in their contacts with different solids, a fact which 

 can hardly be separated from the idea of some community of nature between 

 the capillary force and those of elective attraction. I hardly dare to hint at 

 the existence of some slight misgiving I have always felt as to the validity 

 of the received statical theory of capillary action, which carries with it the 

 authority of such names as those of Laplace and Poisson. Any discussion 

 of this point would be matter for another Section of this Association; and 

 if I here touch upon it, it is only to observe, that my impression of the requi- 

 siteness of a force so far allied to chemical affinity as to be capable of saturation, 

 rests on other grounds besides that of the mere diversity of action above 

 alluded to. But I must remember that you are not met here to listen to 

 generalities, of whatever nature, but that we have plenty of real and spe- 

 cial business before us. 



EQUIVALENTS OF THE ELEMENTS. 



The following is a resume of results of recent researches on the above 

 subject, recently communicated to the French Academy, by M. Dumas: 



Among the simple bodies or elements studied by him, twenty-two have 

 equivalents that are multiples of hydrogen by a whole number, viz. : 



Seven have equivalents which are multiples of lialf an equivalent of 

 hydrogen. 



Cl 

 Mg 



35-5 

 12-5 



Mn 

 Ba 



27-5 I Ni 

 68-5 Co 



29-5 I Pb 

 29-5 



103-5 



Three have equivalents which are multiples of one-fourth of an equivalent 

 of hydrogen. 



Al 13-75 Sr 43-75 Zn 32-75 



Among the comparisons that may be made there arc the following: 



It is seen that on adding 108 to the number for nitrogen we have the num- 

 ber for antimony (14 + 108= 122); and adding it to the number for fluorine, 

 we have the number for iodine (10 + 108 = 127. 



So also on adding sixty-one to the equivalent of nitrogen we obtain that of 



