R. Bunsen on the Washing of Precipitates, 329 
paper, that on cautiously pouring water over it it remains 
completely undisturbed. The washing is effected by carefully 
— vessel, After the filter has in this manner been replen~ 
ished four times with water and allowed to drain for a few 
minutes, it will be found to be already so far dried, in conse- 
pei, of the high pressure to which it has been subjected, 
that without any further desiccation it may be withdrawn, to- 
gether with the precipitate, from the funnel, and immediately 
ignited, with the precautions to be presently given, in the 
ible, 
If the porosity of a paper filter containing a precipitate 
speak presently) to drain crystals from adhering mother li- 
occupied in the filtration is scarcely longer than that needed 
to pour a liquid slowly from one vessel to another. In filter- 
1 grm., successive portions of the liquid were withdrawn, 
and the chromium oxyd contained in them precipitated with 
pe hy ammonia. iquid, 
the quantity of ammonia employed, the time ae ay in boil- 
3 in permitting the precipitate to settle, the angle of 
lon yy the and the size of the filter 
Were the same in all the experiments. All the precipitates 
Ax. Jour. Sci—Szconp Serres, Vor. XLVII, No. 141.—Mar, 1869. © 
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