LEA 
portion into a white oxide, which comes off 
in flakes when the lead is uncoiled. The 
plates are thus treated repeatedly, until they 
are corroded through. Ceruse is the only 
white substance used in oil paintings. It 
may be dissolved without difficulty in the 
acetous acid, and affords a crystaliizable 
salt, called sugar of lead, from its sweet 
taste. This) like all the preparations of 
lead, is poisonous. 
The sulphurets precipitate lead from its 
solutions, the sulphur falling down in com- 
bination with the lead. Pure alkaline so- 
lutions dissolve a small portion of lead, and 
corrode a considerable quantity : the solu- 
tion is said to give a black colour to the 
hair. 
Oils dissolve the oxides of lead, and be- 
come thick and consistent; in which state 
they are used as the basis of plasters, ce- 
ments for water- works, paints, &e. 
In the dry way, lead alone is oxided and 
vitrified. When fused with fixed alkaline 
salts, it is converted into a dark coloured 
scoria, partly soluble in water. The neutral 
salts in general are not acted upon by lead. 
Nitre oxides this metal when heated with 
it, though scarcely any commotion or appa- 
rent flame is produced by its action. Sul- 
phur readily dissolves it in the dry way, and 
produces a brittle compound, of a deep 
grey colour, and brilliant appearance, which 
is much less fusible than lead itself ; a pi o- 
perty which is common to all the combina- 
tions of sulphur with the more fusible me- 
tals. 
The phosphoric acid, exposed to heat 
together with charcoal and lead, becomes 
converted into phosphorus, which combines 
with the metal. This combination does 
not greatly differ in appearance from ordi- 
nary lead : it is malleable, and easily cut 
with a knife ; but it loses its brilliancy more 
speedily than pure lead ; and, when fused 
upon charcoal with the blow-pipe, the 
phosphorus burns, and leaves the lead be- 
hind. 
Lead decomposes sal ammoniac, or muri- 
ate of ammonia, by the assistance of heat : 
its oxides unite with the muriatic acid of that 
salt in the cold, and disengage its volatile 
alkali. When the volatile alkali is obtained 
by distilling sal ammoniac with the oxides 
of lead, the residue consists of the muriate 
of lead. 
Litharge fused with common salt decom- 
poses it; the lead unites with muriatic acid, 
and forms a yellow compound, at present 
used in this country as a pigment. The 
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alkali either floats at top, or is volatilized 
by the heat if strongly urged. The .same 
decomposition takes place in the humid 
way, if common salt be utacerated with, li- 
tharge, and the solut’on will contain the pure 
alkai'. 
Lead unites with most of the metals. 
Gold and silver are di.ssolved by it in a 
slight red heat. Both these metals are said 
to be rendered brittle by a small admixt.ire 
of lead, though lead itself i.s rendered more 
ductile by a small quantity of them. Pla- 
tina forms a brittle compound with lead ; 
mercury amalgamates with it ; but the lead 
is separated from tlie mercury by agitation, 
in the form of an impalpable black powder, 
if oxygen be present, wdiich is at the same 
time absorbed. Copper and lead do not 
unite but with a strong heat. If lead be 
heated so as to boil and smoke, it soon dis- 
solves pieces of copper thrown into it : the 
mixture when cold is brittle. The union of 
these two metals is remarkably slight; for, 
upon exposing the mass to a heat no greater 
than tliat in which lead melts, the lead al- 
most entirely runs off by itself. This pro- 
cess, which is peculiar to lead with copper, 
is called eliquation. The coarser sorts of 
lead, which owe their brittleness and granu- 
lated texture to an admixture of copper; 
throw it up to the surface on being melted 
to a small heat. Iron does not unite with 
lead, as long as both substances retain their 
metallic form. Tin unites very easily with 
this metal, and forms a compound which is 
much more fusible than lead by itself, and 
is for tliat reason used as a solder for lead. 
Two parts of lead and one of tin, form an 
alloy more fusible tlian either metal alone ; 
this is the solder of the plumbers. Bismuth 
combines readily with lead, and affords a 
metal of a fine close grain, but very brittle. 
A mixture of eight parts bismuth, five lead, 
and three tin, will melt in a heat which is 
not sufficient to cause water to boil. An- 
timony forms a brittle alloy with h-ad. 
Nickel, cobalt, manganese, and zinc, do not 
unite with lead by fusion. 
It will appear from the foregoing obser- 
vations, tliat the uses of lead are very ex- 
tensive. It is easily reduced to thin sheets, ' 
adapted to the covering of buildings ; to be 
formed into pipes of all sizes, and fitted for 
divers purposes. Its oxides are used as 
paints ; in the manufacture of glass ; and in 
the glazing of earthen-ware, &c. 
Lead, black. See the article Iron. 
Lead, sugar of. A salt, denominated 
from its composition, by modern chemists. 
