Physics and Chemistry. 411 
e 
to a determination of the amount of active oxygen present.— 
60 i 69. Be Po Be 
15. On the preparation of concentrated Lodhydric acid.—The ex- 
tensive demand for a concentrated solution of iodhydric acid in the 
€ . 
lodine being added gradually,—and the whole is exposed to a gen- 
tle heat, the receiver being kept cool by ice. On repeating the 
xi, 125, Feb., 1869. G. F. B, 
es Platinum Compounds,—ScunEwer has 
is poured into a solution of platinic chlorid, containing 0°01 grm. 
Platinum, the fluid is colored at first dark yellow, then brigh 
orown, and finally becomes so dark b as to be o If 
long as each addition increases the depth of color produced, it will 
found that nearly three molecules of the tin salt will be re- 
Am. Jour. Scr.—Seconp Serres, VoL. XLVILI, No. 144.—Nov., 1869. 
28 
