248 S& P. Sharples—Precipitation of Antimonous Sulphid. 
0°7782 gr. K,Cr,0, gave 0°4023 gr. Cr,0, = 68°02 pr. ct. chro- 
mic acid. 
kage hg K,Cr,0, gave 0°8102 gr. Cr,0, = 68°13 pr. ct. chro- 
ger 
The Pa requires 68°04 pr. ¢ 
Alumina treated in the same P ats is also very easy to 
sh. 
2°4097 gr. potassic alum gave 0°2626 gr. Al,O, = _—— = pr. ct. 
1:9571 gr. “ -0'2130 gr. "= 8 pr. ct. 
The formula requires 10°86 pr. 
The Lee applies with slinbet equal advantage to iron. 
Weighed ns of ammonio-ferrous sulphate were dissolved in 
water, an ais chlorid sidid 4 in large excess to furnish solid 
matter to be washed out. The iron was then oxydized with 
nitric acid, precipitated by ammonia, and evaporated as above. 
1°5824 gr. gave 0°3229 gr. Fe,O, = 14°28 pr. ct. Iron. 
1°4840 gr. gave 0°3019 gr. “ = 14°24 pr. ct. Iron. 
The formula requires 14:29 pr. ct. 
Nickelous sige also loses its gelatinous character when 
treated as above. 02201 gr. metallic nickel gave, after solu- 
tion, precipitation as carbonate, and reduction by hydrogen, 
metallic nickel = 99-91 pr. ct. of the quantity taken. 
Gobelins carbonate may be treated in the same manner, but 
the alkali cannot be completely Miegoey out, and the method is 
in this case not to be recommen 
It seems at least extremely some that other gelatinous 
oxyds and hydrates will give equally good results when treated 
in the mannet which I have described. 
§4. 
On the eens . — sulphid -™ boiling solutions ; 
EPHEN P. SHARPL 
In the one 3s antimonous sul bia I have found it 
of very great advantage to employ the following process : 
the solution, containing as usual tartaric and free chlorhydric 
acid, a current of sulphydric acid gas is to be passed, the liquid 
being, — the passage of the gas, gradually heated to <a 
boiling The boiling is then to be continued for 15 
20 Dandies, She current = gas passing uninterruptedly, aantil 
the voluminous sulphid has become a dense granular powder, 
occupying but a small Sortie of the o volume of the 
Th 
sulphid. e sulphid may then be washed with great facility, 
and dried upon a sand filter at 200°-800° C. xn the deter- 
minations of reenciptdiee made in this Laboratory for some years 
have been executed in this manner, the results leaving nothing 
ie Set ln a la 
