Chemistry and Physics. 379 
effected hot, the stannic oxide and the lake resulting are both in- 
soluble ; while if the heat used be very moderate, a purple of Cas- 
sius is obtained in this way — soluble _ ammonia.—Moni- 
teur or III, ii, No. 372, 1007, Dec., 1872. G. F. B. 
t the Determination of Free Oxygen in Solution.—Scuit- 
ZENBERGER and GERARDIN have made some experiments upon the 
determination of free oxygen by titrition with a graduated solu- 
tion of the new sodium hydro- (or more oo nyt pe) ee 
phite, discovered by the former, which, a well known, has’ 
strong attraction for pend so In eed of fies oxygen, "it Se 
comes sulphite at on 
HNa80,--0 = =HNad0,, 
A half hour before the determination, a flask i 60 to 100 «ec. 
capacity is filled be ap 9 Ay full with water, a spiral of leaf 
zinc is placed in it, and to it is added 10c.¢, of a solution of hydro- 
sodium wg of 20" B. It is then filled with —_ and closely 
phite does not affect it) used as an indicator. Into a burette of 
50 to 60 cc, capacity divided into tenths ¢.c, the hyposulphite 
solution is placed. Its titer is first ascertained by noting the 
amount necessary to decolorize the copper solution, Then at once 
and from the same burette, the solution is added to the liquid to 
be examined until it is decolorized. During these LAE the 
Opening of the burette is kept below the level of the 
ae calculation, the amount of dissolved oxygen is seal as- 
ained.—Moniteur Scientifique, UI, iii, No. 373, January, = 
. 
Gs 
mine, has lately, in connection with GryeEr, undertaken to study 
the results of this reaction in other cases. "They find that both 
aniline and toluidine, heated with pier i coranee in a sealed 
tube to 160° for four or five hours, pro a blue coloring mat-- 
ter, ‘whieh they call azodiphenyl blue. The reaction is: 
C,2H,,N,+C,H,N=C,,H,,N;+NHs. 
is a oe aaK dark hes in “in color, insoluble 
u 
ie it noes a leucobase the aniline-violet obtained by Girard, 
