246 = J. H. Talbot—Separation of Tin and Tungsten. 
a ae eae in another as ae sulphid by ignition 
na currrent of SH,. In this man 
0°3132 gr. Mn,P,0, gave 0°3126 gr. aa P,0, = 49°56 pr. ct. 
Mno. 
0°3786 gr. Mn,P,O0, gave 0°2310 gr. MnS = 49°65 pr. ct. MnO. 
The formula requires 49°64 pr. ct. MnO. It is perhaps worthy 
of notice that ammonic sulphid does not fe ile iad 
manganous pyrophosphate under the circumstances above de- 
scribed. The greater portion of the salt is Pee ere at once 
as crystalline ammonio-phosphate of mangan 
2. On the quantitative separation of tin so tungsten. 
The quantitative separation of tin from tungsten has always 
been regarded as a difficult robe not hitherto solved in a 
satisfactory manner. The following method will, I think, be 
found to leave nothing to be desired as respects both ease and 
accuracy. It depends upon the fact that stannic oxyd, SnO,, 
is reduced by potiasit cyanid with great facility, while tungstic 
acid, WO,, undergoes no reduction, even when heated with the 
ceyanid to a ‘high temperature. The oxyds of tin and tungsten 
are to be heated in a porcelain crucible with 8 or 4 times their 
ized, ie thoroughly mixed with the ‘two oxyds. The mass is 
kept fu used for a short time, when the tin separates in the form 
of metallic pies while the tungstic acid unites with the 
alkali of the potassic cyanate and carbonate present. After 
cooling, the mass is to be treated with hot water, which dis- 
solves the alkaline tungstate and other salts, and leaves the tin 
metal. This is to be filtered off, washed, ‘dried and aude 
cipitated tungstic acid by means of an alkali. To test the 
method, weighed porte of ne stannic and tungstic oxyds 
were mixed and treated as abov 
0°6662 gr. SnO, and 0°5880 gr. Ho: gave 0°6679 gr. SnO, = 
53°24 Be et The calculated percentage of stannic oxyd is 
here 
0°7098 ly ‘Sn0, and 075460 gr. WO, gave aie oe a Sn0, = 
56°51 pr. ct, the calculated percentage bein 
05878 gr. SnO, and 0°4373 gr. WO, gave 0s gt Sn0O, = 
55°43 pr. ct., the calculat reentage bei 
bagi ae! SnO, and 0°4334 gr. O, gave ee gr. ‘sn0, and 
or, WO,. This corresponds to 
