( ) 
It is plainly 'this fulpfaurous part that rifes upon Iron 
and polifh’d Steel when beared, and gives them all thofe 
different Colours, from a Yellow, to a Violet, Water- 
Colour, or Black. 
If one continues to hold this Piece of Iron on the 
Charcoal, it intirely melts ^ and at the fame time calls 
forth very bright Sparkes in a great quantity, fometimcs 
to above a toot ancc from the Cod. 
If one faves it files off during this fparkling, by 
holding a. Sheet of Paper under the Ccal 5 we find 
that they are fo many very fmall Globules of Iron, 
and the greateft part of them hollow. 
All the Iron »^hat is held in fnfion upon the Coal, 
flies away in fparkles after this manner, rhill none re- 
mains. Sometimes the Metal leaves off fparkling, when 
the Coal is in part confumed, and cover’d w ith a Bed 
of Cinders, upon which lies the meleed Iron. For as 
the fparkling of the Iron Teems to me to proceed from 
nothing but the oily parts of the Coal ading upon 
tbofe of the Metal, the Cinders hinder this Oil from 
palling from the Coal to the Iron, fo that it remains 
quietly in lufion. But if thro’ any fliake, or the like 
accident, the Cinders are fo removed that the Iron 
comes to touch immediately, the Coal, it will begin to 
fparkle afreili. Sometimes the Heat that keeps in fufion 
the Metal, vitrifies alfo the Cinders ^ and this vitrified 
Matter mixing wiih the Metal makes a confiderable 
Ebulfrion. If one at this inftant withdraws the Metal 
out of the Focus, it appears half vittified, or reduced 
to a blackifii friable Mafs. O.hertiines this vitrified 
Matter fwims on the fuiface of the Metal, and there 
forms it felf into Drops, that are fometimes dear and 
tranfpirent, and other times opakc, according as it is 
more or lefs mixed with the Metal. 
Lil 
