330 Ri. Bunsen on the Washing of Precipitates. 
were washed with hot water, and, after burning the filter, igni- 
ted over the blowpipe fora few minutes ; ; in wei 
platinum crucible was tared by one of about equal weight, 
and vor position of equilibrium of the beam determined by 
vibrations. 
I a attempted to filter one of the precipitates in the or- 
dinary way. = amounted to 2; and consequently, from the 
table, 8:4 fresh additions of water were required in order to 
wash the ae eto the ;;3,, part. The times re 
were as follows 
In transferring the precipitate from poss beaker) 4 
owing it to drain 
For the first addition of water és run through, 
i 
con 
© third “ “ 80 
Total length of time - - - 238 
At this point the experiment was discontinued, as the fil- 
trate Masi di turbid. A second experiment failed from the 
same ¢ 
_Aesondingly I attempted to wash the precipitate by decan- 
volume of the precipitate amounted to about 
ib centims,; the quantity of water required to fill the beaker 
_ Was seven times the volume of the precipitate; hence — — was 7, 
and the requisite number of decantations to reduce the 5 eniotat 
of impurity to the ,,1,, part was 52. The times observ 
were as follows :— 
II. 
For the first decantation to run through the filter. -- 15’ 
at second “ “ “ 12 
s third 6 6 & 18 
= fourth “ ‘ éé 15 
ee “ om 18 
In transferring tia sietinksle t vO the filter | 3... an 30 
equired in washing ag 
Weight of ie the the preiate Septet. | 02458 g 
NRE AY os 1050 fe 5 anes 
ees Ul. : 
Experiment repeated. Number of deeantations 7. Other ci 
cumstances the same as in the foregoing determination. 
inl ies 
Weight of the precipitate __ __. 0°2452 grm. 
Volume of Niahaparar : 1200 cub. centim*. : 
ee ee ee ee 
