56 Hf, Wurtz on the Indigo Test. 
bya hlorid of iron is also rendered almost completely colorless 
y a little chlorid * cobalt, but this is of course a matter of no” 
In of mant 01 
which I he having found it to add materially to the pee = 
* A few other observations were made e upon the effects of mingling colored solu- 
tions. The nitrates of cobalt and nickel when mixed in proper proportions neutral- 
ize each other just as the chlorids $ With the a. of nickel and the nitrate — 
cobalt t nis probably more perfect ids 
used. With chlorid of cobalt and "hilente of nickel the resultant color was rath 
brownish than grayish. The nitrates of copper and cobalt did not seem to 
ra 
co nae came anne into the green 
the chlorid, and every trace of blue Sree Sh leaving the ne. cat with the peculiar 
_ of cobalt also, vo perfect neutrali- 
upon sin 
a solution mater and i wgear o furnis a new and valua' able means of i oe 
igating this importan 5 cecbiin The aie ect will therefore be resumed at a 
not seem to be much present prospect of devising a rand for 
the expensive chlorid of cobalt for nullifying blue and green colors, in the 
ligo test. The co i 
tion eh TO pe o oxygen. 
tion destroys the green color of chlorid of nickel as perfectly as chlorid of pee 
the resultant tint moreover being extremely similar; with chlorid of chrommm 
in certain proportions an a Sg among a was pro oduced, but in whatever propor- 
_ tions _the two were mixed, a esidual red or blue was always left; with 
id of copper a fine deep violet: Stine color, like that of the ammonia- sulphate, 
@ here to urge upon the attention of chemists this pone pein! ie =e 
erence of colors with each other when in admixtur 
wed and cog tara! by the ions of Gor- 
ianese compounds (Liebig und pi 's Saket fiir 1853. 
, xvi, 416), which explain perfectly the discrepant ob- 
! i ors of ay 
upon 
ri- 
i 
of « othe substances prec precipitated Wi : 
o! 1 investigation, and woul probably lead us to new 
ick detection of cxrtain © ubstai ss a 
3 to obtain ¢ cas double chloride corresponding to * 
chlorid e green and blue Pegsane' but 
