t 3o| 1 
fefed to cool, and then a globule of metallic lea<j 
will be left upon the coal. If any iron is contained 
in the lead ore, the lead, which is melted out of 
it, is not of a metallic fliining, but rather of as 
black and uneven furface : a little borax muft in 
this cafe be melted with it, and as fopn as no bub-, 
ble is feen to rife any longer from the, rnetal into 
the borax, the fire muil be difcontinued : when 
the mafs is grown cold, the iron will be fouud 
Icorified with the borax, and the lead left pure, 
and of a fiiining colour. 
SECT. XXXVIIL 
The borax does not fcorify the lead in thele 
fmail experiments, when it is pure; if the fiarhe 
is forced with violence on it, a bubbling will enfue,|- 
refembling that which is obferved when boraj^ 
difiblyes a body melted with it, but when the fire 
ceafes, the flag will be perfeftly clear and tranfpa- 
rent, and a quantity of very minute lead particles 
will be feen fpread about in the borax, which have 
been torn off from the mafs during the bubbling, 
SECT. XXXIX, 
If fuch a lead ore (Se£t. xxxviL) is rich in filyerj 
this lafl; metal may likewife be difcovered by this, 
experiment ; becaufc, as the lead is volatile, it 
may be forced off, and the filver remain. To efieft 
this, the lead, which is melted out of the ore, 
muft be kept in conftant fufion with a flow hear, 
that it may be confumed. This end willbe fooner 
obtained, and the lead part quicker, if, during 
the fufion, the wind through the Blow-pipe is di- 
reded immediately, though not forcibly,, upon the 
melted mefs itfelf, until it begins to cool,, then the 
fire mufl: be direded on it again. The lead, which 
