179 
Lead l 
water and nitric acid, and converted into a sulphat by 
means of sulphat of soda as before* 
Lead is separated also from iron and copper by dis- 
solving both in nitric or muriatic acid, and adding suL 
phat of soda to precipitate the lead. If the nitric acid be 
used, some of the oxyd of iron will first precipitate as a 
brown red ochre, which should be removed. 
The same method will separate lead from tin, cobalt* 
and zinc. 
The composition of the sulphat of lead artificially form- 
ed in these processes, has been given with some small va- 
riation by different chemists ; Klaproth estimates it as fol- 
lows. 
100 parts of sulphat of lead, dried at a low red heat , are 
composed of 73.96 of oxyd of lead and 26.04 of sulphu- 
ric acid,, and the above oxyd of lead is composed of 69.44 
of metallic lead, and 4.52 of oxygen. This is not the on- 
ly state of oxygenation of which lead is capable, but it is 
that in which, according to Klaproth, it is inferred to ex- 
ist in ail the native salts and oxyds of this metal hitherto 
analyzed. 
It must be observed however, that this calculation gives 
a much lower state of oxygenation than is found by other 
experiments, as will be noticed presently, and the estima- 
tion of the quantity of metallic lead is made by other che- 
mists, and even in other experiments of Professor Klap- 
roth, to rise as high as about 71 per cent. Mr. Hatchett 
reckons it to be 70,9. 
But where the muriat of lead is free from other admix- 
ture, the quantity of metal may be estimated without con- 
verting it into a sulphat, by the following data 100 parts 
of lead dissolved in nitric acid, and decomposed by drop- 
ping in muriatic acid as long as any turbidness ensued, 
and evaporated to perfect dryness (but short of volatiliza- 
tion of any part of the combined muriatic acid) produced 
