Heinrich Rose. 313 
salts of antimony and copper, the Fahlerz of the German min- 
eralogists, or tetrahedrite, of whose composition little was known 
from the want of accurate methods for their analysis. 
In a chemical point of view they are a continuation of the great 
work of Berzelius on the sulphur-salts, and show that the dis- 
tinction made by him of sulphur acids and bases is as marked in 
nature as in the products of the laboratory. They also suggested 
the isomorphism of the sulphurets of copper (Cu,S) and silver 
(AgS), and the consequent necessity of halving the atomic weight 
of the latter; an idea which he developed at length in several 
Subsequent papers, which gave rise to his last discovery, and 
was the subject of his latest communication, written but a few 
months before his death. 
mined. The hypophosphorous acid, discovered in 1816 by Du- 
g, was erroneously considered by him to contain half as much 
oxygen as the phosphorous acid, and Davy had mistaken the 
relation of the oxygen in all three of the acids, Thus the sub- 
ject was in a most unsettled state; and, to increase the confusion, 
simultaneously with the work of Rose came out a research by 
Dumas, followed by one from Buff, both differing from the con- 
clusion at which Rose had arrived. Rose was led in consequence 
to reéxamine the points about which he was at variance with 
these chemists. The results of his new investigation were pub- 
lished in 1832; it is the most important paper of the series, and 
1s “Aang: by an abstract of the former ones, from which a 
sufficient idea of them may be obtained. 
Am. Jour. Sct.—Seconp Series, VoL. XXXVIII, No. 114—Nov., 1864. 
40 
