Technical Chemistry. 117 
When the proper quantity of sulphate of lead has been added to the 
lye and the decomposition is finished, the contents of the kettle must be 
thrown into a vessel containing water in order that the sulphate of soda 
‘which has been formed may be retained in solution, which would not be 
the case if no water were added to the mixture. The oxyd of lead, which 
is in the form of exceedingly fine crystalline scales of a light yellow ish 
red color* and of great — is ~~ deposited ; after being thoroughly 
washed, to remove the sulphate of soda, it is dried and finally ignited in a 
reverberatory- furnace—the args being subsequently allowed to cool as 
slowly as possible. 
s thus seat ed the oxyd is an exceedingly soft eps of a yellowish 
red color like prepared litharge; it contains about 2 ent of alumina 
which can not readily be removed, but which is not at “all conaseieaia to 
- its use in glazing pottery, and also a larger or smaller quantity of carbonate 
of lead according as the soda lye was more or less contaminated with car- 
bonate of soda. 
The crude sulphate of lead as it comes from the print works should be 
agitated and washed with water—or, better, forced through a fine seive 
in order to break up lumps and to remove any foreign substances, —be- 
fore being used. 
, 18 
13. Clacneag of “Mehiianted Cloth before rt go A ; by J. Lewentnat. 
—It is weli known that cotton cloth upon which alumina or iron mor- 
dants have been gure must be submitted * the so-called dunging pro- 
cess before it can be « 
ing it readily soluble so that it can be easily removed from the clot 
y direct experiment he has satisfied himself that the addition of malt 
to baths of bids » (previously ssp or of cowdung, is decidedly leerern 
A temperature of 35° to 40° R. {ou to [ap alc that 
’ the malt shall act pooutalies 
__ * Ifa more concentrated be used, say of 40° somewiat lager ry 
| ey of = eek. red color cng ig 4 = 
