260 
MANUFACTURE OF ACETATE OF LEAD. 
The mother-liquor, containing neutral and basic acetates of lead 
and other metallic salts, may either be treated with vinegar, evapo- 
rated, recrystallized, and the residue employed as washings in sub- 
sequent operations, or it may be decomposed by carbonate of soda 
or lime, and used as carbonate of lead, or dissolved in acetic acid, 
and the supernatant acetate of soda or lime recovered. 
The vessels employed in the manufacture of acetate of lead are 
in most cases made of lead. In Wales the mixing pans are of lead, 
three-quarters of an inch thick, seven feet long, by four and a half 
feet wide, and one foot deep. These pans are set on iron plates 
over arches, and the fire-places are outside the building in order 
that the acetate may not be darkened by the sulphurous vapors 
from the coal. The crystallizing pans are of wood lined with thin 
copper, and are about four feet long by two feet wide, and from six 
to eight inches deep, sloping inwards at the edges. At Pitch- 
combe the mixing and crystallizing vessels are both of copper, 
having a strip of lead soldered down the sides and across the bot- 
tom of the vessel to render the copper more electro-negative, there 
is thus no action on the copper from the acetic acid. Great care is 
requisite in the drying of the sugar of lead ; the temperature of 
the drying house should not exceed 90° Fah. In Wales the heated 
air of a stove placed outside the drying house is conveyed through 
pipes passing round the interior ; at other places steam heat is em- 
ployed for this purpose, which is much to be preferred on account 
of its being more easily regulated. 
We now come to speak of the product of sugar of lead from a 
given quantity of litharge. 112 lbs. of good Newcastle litharge 
should produce 187 lbs. of sugar of lead by the employment of 127 
lbs. of acetic acid of sp. gr. 1.057, but not more than 180 lbs. is 
obtained in practice. The quantity of produce given in Ure's 
Dictionary of Arts and Manufactures and in other works, is evi- 
dently a misprint, being almost three times. the weight of the lith- 
arge employed. A manufacturer of sugar oflead would indeed be 
fortunate who could obtain such a return. In one works in Wales, 
a ton of Welsh litharge produces, with the acid obtained from one 
ton of acetate of lime, from twenty-eight to thirty cwt. of sugar of 
lead; and in another manufactory one ton of best Newcastle lith- 
arge, with the acid from one ton and a half of acetate of lime, pro- 
duces thirty-three cwt. of acetate. 
