( 44 ^ ) ] 
"f-ciind'that the fine Gold Coiour was nothing clfe but Su!- J 
•'phur: There was alfo another Piece, which they faid was j 
Copper. One of thefe Minerals was mix’d with a little ] 
■ftony Matter, juft like Particles of Sand, which Teem’d 
Tome heterogeneous Matter, to be united to theother Parts 5 
the Mineral. i 
I Teparated Tome of the Sfony Matter from the reft, ] 
and placed it before the Mictofeope^ and found that Tome I 
‘Of the Particles, of which it is compofed, had asfmooth ] 
and exadt Sides and Angles as any polifh’d Diamond can hj 
4iave, that is to fay, when they were not united, or lay 
• under others^ but where there was a union of the Parts, ] 
there appear’d feveral fuch Circles or Circumferences as | 
were in Figure 3 and 5 -. Tome of ’em having particular 
4ides, one of which was twice as broad as another. 
Thefe particular Rings or Circles 1 judged alfo were 
•occafion’d by the Increafe or Coagulation of new Matter: 1 
I took a great deal of Pleafure in viewing them, for they 
appear’d as clear as Chryftal. Both the Gold and thq Cop- 
per, that Teem’d to be in thefe Minerals, were nothing l 
elfe but Sulphur. ‘ f ] 
My Intention was to have left off here, but’ upon R- f ; 
cend Thoughts I fhall trouble you with what follows. I ' I 
formerly fliew’d the Circulation of the Blood in an Eel, | 
and my Cufio ii was to put the Eel into a long Glafs Tube | ' 
with the Tail uppermoft : But I have left off that way } 
for Tome Years, and now I prepare Copper Plates of about { 
a Foot long and feven Inches broad 5 one end of w'hich 
of the extent of an Inch I bend, and at the other end I ! 
Huake a fquare Hole of five Inc! es long and two broad, in 
which I put little Glafs Plates as dear and as thin as I caa [ 
polfibly procure them ; Upon fuch a Glafs Plate I lay one ' 
of the fnalleft Eels I can get, which are fometimes as big 
■a-s ones Finger^ then I bind the Head and the beft part 
the Body of the Ed about with a Linnen Cioth, to the i 
, cud 
