le 3 Scientific Intelligence. 
It was evident, therefore, that the 400 lbs. of pig-iron used did séally 4 : 
contain nearly and a half of copper. It more 
that copper cannot be removed from iron by puddling. Calculating how 
much copper ought to be left in the iron which lly removed 
rom the furnace, in case none had been = in the slag, it is found that 
there should be 0°58 per cent, almost exactly the quantity obtained m 
analysis No. 3.—Dingler’s lei laecke Joma 1860, clv, 
2. Preparation of Oxyd of Lead free from Copper and Tron; ; by Ta. 
ich. —Of the many plans which have been proposed for utilizing 
the sulphate of Jead which is formed in considerable quantity as a secon 
dary product ia the preparation of alumina mordants at print works, the 
method of reducing it in furnaces to the metallic state has been gr fre- 
quently resorted to, since the quality of the lead thus prepared is of pect 
liar excellence. Instead of thus reducing the sulphate of Jead, Wichmann 
proposes to convert it ie into oxyd of Jead, maintaining that the 
oxyd thus prepared being uncontaminated with copper or iron will be 
well suited for the ies iar of white cs for pottery—[ probably also 
for making flint giass| it being somewhat ult to obtain in commerce 
oxyd of lead which does not contain traces ‘of these impurities. In his 
method, suggested by that of Mohr* - a preparing caustic baryta, a quan- 
tity of caustic soda lye of from 28° to 30° (B.)= about 1-25 sp. gr., hav- 
ing been brought to boil in an iron Kettle, the sulphate of lead is added 
to it little by little, with constant stirring, oxyd of lead and sulphate of 
soda being produced. The amount. of sulphate of lead which shall be 
added to a kettle of soda, and a is somewhat less than the pe 
which theory would indicate, must etermined once for a by direct 
experiment} sulphate of lead being added until the sharp caustic taste a 5 4 
the soda is no longer manifest. It is en however, to leave some 
_ soda in the solution Jest a portion of undee epee sulphate of lead should 
contaminate the oxyd of lead which is faeiiaal Ithough a small amount 
of the latter will combine with the soda and remain in solution, During 
the belay. the decomposition is rapid, and complete, unless the soda lye 
tained much carbonate of soda in which case a white scum of cal 
sles of lead will — 
an ‘equivalent ‘Seige ot albica ay nitrate of fdhoring added. As soon as the ba 
ryta sa completely dissolved, the hot solution shpuid be be rapidly filtered in of 
der to separate any sulphate or carbonate of baryta which may have been formet 
erop of crystals of hydrate ef baryt . These cryst e 
from the solution of nitrate o u funnel loosely plugged with cotton and 
drying completed [according t | ofa 
required fur pu where the adhering nitrate of soda should be avoided the 
ate of baryta may be ryst ° of the nitrate of baryta 
use chlorid of barium—or in pla tash ; bu 
of chlorine in the product would be more objectionable than that of nitric 
mall seale the pr iling is best conducted i ge but where 
larger Taser are desired a covered iron kettle may be u 
met ing caustic alkalies, or ee chiv as Pirate. ani 38; ia 
hod : 
Chemises Conrallat, 1856, [N. F., 
‘+ For y method of obtaining ‘he ‘ecicht of moist hag oy of lead, see Mr. 
F. Shiny ee: in the March No. of this Jourual, [2], xxix, 280.] 
