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H, Wurtz’ Contributions to Analytical Chemistry. ~ 879 
n exposed for some hours to a very gentle heat to drive oif 
all traces of free acid, was deliquescent in moist air, and gave 
with water a clear dark brown solution leaving little or no insol- 
uble residue. It still contained a trace of chlorine. 
The influence of the codperation with the nitric acid of some 
other oxydizing agents was tried, but so far without success. 
Those experimented with were the deutoxyds of lead and man- 
einese and arsenic acid. Chlorine was still present after four 
_ Waporations with the acid in conjunction with the deutoxyds. 
VER eee Se ape et aa Gh ee ng Pen ky 
. Hanganese—Both the dry chlorid of manganese and its 
solution lost all chlorine by one evaporation with excess of 
nitric acid. 
12. Cobalt.—Chlorid of cobalt was also converted entirel y into 
nitrate by one evaporation. In applying the indigo test | 
nitric acid in cobalt solutions, the colors of which interfere with 
it, I resorted to the ingenious expedient for the application of 
Mum's manganese tests to these solutions given by Dr. Gibbs, in 
his “Contributions to Analytical Chemistry,”* which consists in 
Previously neutralizing the color of the cobalt solution by adding 
®solution of chlorid of nickel. ease 
48. Nickel—Chlorid of nickel behaved with nitric acid pre- 
asely like chlorid of cobalt. The green color of nickel solu- 
HS interferes still more with the indigo test than the cobalt 
colors, but the difficulty is readily and effectually overcome by 
Dr, Gibbs's method, that is, by previously destroying the green 
“olor by addition of chlorid of cobalt. rs 
14. Zinc.—A fer five repetitions of the treatment with nitric 
cof ap. gr. 129° the ehlorid still retained chlorine. Pure 
peed chlorid of zine was then boiled with acid of sp. gr. 1-43. 
witlissolved gradually, with evolution of brown gas, and gave 
po) 
i 
d, the residue was boiled with water. A white sub- 
Stance remained undissolved in considerable quantity. The 
Solution contained both ehlorine and nitric acid in large quan- . 
Uty, and the white substance having been well washed, contained 
but ittle chlorine. and was most probably one of the basic 
, Utrates of Grouvelle and Schindler.t 
Cadmium.—The chlorid, like that of zinc, resisted five 
& ), 
Tebetitions of the action of nitric acid of sp. gr. 1:29. Pure 
3 h a 
_ “WYstallized chlor; d of cadmium, dried at a gentle heat to expel 
* Am, Jour. Science, [2], xiv, 204. + Gm. Handbuch, iii, 82. 
