Part III. Of Regular Stones. 311 
Windows , inftead of Glafs. Ambrofinus (a) mentions a M U bi 
Lead-colour d fort fo big, as to make not only Tiles, but ^p^« 
Tables. 
The BONONIAN STONE , Prepared and given by 
Fr.WiUugbbyYio^. Tis fomewhat Affile, and may be here 
ranked. Now of a grey ifh colour, and in Tome places like 
the Rombick, Lead-Spar. No Acid will touch it. Its qua- 
lity of fhining in the Dark, after its being expofed a little 
while to the Sun, is now loft. See the manner of its prepa- 
ration in Wormius. Given in Powder, (b) or the infufion $ Muf - 
. r • r i • > i - n r- • / Wormian. 
or it, arter calcin d, is a itrong hmetick^ 
An odd SPAR, Green by day $ by Candle-light of an 
Amethyftine colour. Softer than to cut Glafs, yet harder 
than the common Rhombick. Lead-Spar. 
A FLORENTINE SLATE. A fort of Saxum fiffile. 
Hereon is naturally reprefented the PROSPECT of a City , 
Houfes, Churches and Steeples, Handing in length. To 
make them all vifible, it muft be wetted. > 
ANOTHER, with the PROSPECT of a TOWN, lying 
round upon the fide of a Hill. 
Another with the like PROSPECT 3 but (hewing it, as 
at a much greater diftance. 
Another, with one half of the TOWN on a Rock, the 
other in a Plain. There are fome of this kind in Sepaliuss 
Mufaum. 
A SALTRAM SLATE. Very like to Efford-Jlate (ufed 
for Writing,and Mathematick Schemes ) but not all out fo 
good. 
An odd SLATE with yellow Mundick in fmall Grains 
or Sparks immerced throughout the body of it. 
RUMPLEY-STONE. A common blewiih Slate, for 
colour and fubftance. But excelleth, in that it rifes large 
enough for Building. It may be cleft as thin as you pleafe. 
A kind of whitifti Slate, mixed with a rufly Iron-colour s 
plentiful ifldfome jft^fie^ 
Some others} one grey and fpotted with tawny. 
Another, of a brown Purple. A Third, Red. Thefe abound 
in the High- Ways about the Mines in Cornwall. With thefe 
may be placed. 
The WAXEN VEIN. Ludus Helmontij. AStonecom- 
pofed of two diftincl: Bodies. One, and the far greater, is 
of 
