Penfylvania, Philadelphia. 65 



length of a foot, and of the thicknefs of a middle- 

 llzed man's leg. They were not fo transparent as 

 the former. 



THE cubic Pyrites of Bifoop Browallius,* was 

 of a very regular texture. But its cubes were dif-' 

 ferent in iize, for in fome of the cubes, the planes 

 of the fides only amounted to a quarter of an 

 inch, but in the biggeft cubes, they were full 

 two inches. Some were exceedingly glittering, fo 

 that it was very eafy to be perceived that they con- 

 iifted of fulphureous pyrites. But in fome, one or 

 two fides only glittered fo well, and the others 

 were dark-brown. Yet moft of thefe marcafites 

 had this fame colour on all the fides. On break- 

 ing them they (hewed the pure pyrites. They 

 are found near Lancafter in this province, and 

 fometimes lie quite above the ground; but com- 

 rnonly they are found at the depth of eight feet or 

 more from the furface of the ground, on digging 

 wells and the like. Mr. Hefjelius had feveral pieces 

 of this kind of ftone, which he made ufe of in 

 his work. He firft burnt them, then pounded or 

 ground them to a powder, and at 1 aft rubbed 

 them ftill finer in the ufual way; and this afforded 

 him a fine reddiih-brown colour. 

 FEW black pebbles are found in this province, 

 which on. the other hand yields many kinds or 

 marble % especially a white one, <with pale -grey bluijh 

 [pots,, which is found in a quarry at the diftance or 

 a few Ertglijh miles from Philadelphia, and is very 



Pyrites cryftaliinus, Linn. Syft. nat. 3. p. 113. Marcba/it<f 

 cdrictf ttflelarss. Waller tufs Mineralogy, p. 211. Mafcajft*, 

 cryftalii pyritafj } Marcafites. Forfteifo Introd. to Mineralogy, 

 39.' 



VOL. I. F good 



