(/ 



PROCEEDINGS 



OF THE 



AMERICAN ACADEMY 



OF 



ARTS AND SCIENCES. 



VOL. XV. 

 PAPERS READ BEFORE THE ACADEMY. 



RESEARCHES ON THE COMPLEX INORGANIC ACIDS. 

 By Wolcott Gibbs, M. D., 



Rumford Professor in Harvard University. 

 Presented June 24th, 1879. 



I propose the term " complex inorganic acid " for a class of com- 

 pounds which may be considered as formed by the union of two or more 

 acids with elimination of water in such a manner as to form a whole 

 which in its chemical relations behaves like an acid containing a single 

 radical. Compounds of this character were observed at an early period 

 in the history of chemistry, but their real nature was for a long time 

 entirely unknown, and our positive knowledge of the subject dates from 

 the discovery of the silico-tungstates by Marignac in 1861.* Berzelius 

 had long before described and analyzed a compound which we should 

 now write 



3 Si0 2 . 2 V 2 5 . 2 P 2 5 . 6 H 2 0, 



the chemical relations of which are still to be studied.f He had also 

 noticed the formation of peculiar yellow compounds when phosphoric 

 or arsenic acids are digested with molybdic teroxide.t These were 

 again noticed and partially studied by Svanberg and Struve,§ who 



* Ann. de Chimie et de Physique, (4,) iii. 55. 



t Lehrbuch der Chemie, iii. 3058. 



X Lehrbuch, iii. 1044. 



§ K. Sv. Vet. Handlingar, 1848, p. 1. 



VOL. XV. (N. S. VII.) 1 



