546 
LEAD. 
pointing out, as the metal is daily employed for 
some purpose or other, in almost every family. It 
is easily extended into thin plates, though its tena- 
city is so trifling that a leaden wire a tenth of an 
inch thick, will not support a weight of thirty 
pounds. Sheets of lead are made by passing this 
metal, without heat, between two cylinders, or 
rollers of iron, by which means they are rendered 
of an uniform thickness, and as smooth as the rollers 
themselves. This is called milled-lead, and it is 
said to be harder and more brittle than cast sheet- 
lead, which may be safely bent in any way without 
cracking. The cast sheets of lead are made by 
pouring this metal, when fused, upon the top of an 
inclined table with a flat surface. If the sheets are 
required to be thin, the bottom is covered with a 
woollen, and above this with a linen cloth, neither 
of which is at all scorched by the metal ; and the 
thickness of the sheets will depend, in a great de- 
gree, on the velocity with which the melted metal 
descends. For making thick sheets of lead, the 
bottom of the table is covered with damp sand, pro- 
perly levelled, and the fused metal is conducted over 
it by a wooden strike, which bears on the borders of 
each side. 
While lead, so well known for its great use in 
painting, is nothing more than sheets of this metal 
dissolved by vinegar. In France they put, for this 
purpose, some weak vinegar into glazed earthen 
pots, upon which the plates of lead, loosely rolled 
up in a spiral form, are placed, so as not to touch the 
