4 



Penfyhania, Philadelphia, 83 



the cubes, the planes of the fides only 

 amounted to a quarter of an inch, but in 

 the biggeft cubes, they were full two inch- 

 es. Some were exceedingly glittering, fo 

 that it was very eafy to be perceived that 

 they confifled 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 breaking them 

 they mewed the pure pyrites. They are 

 found near Lancajier in this province, and 

 fometimes lie quite above the ground ; 

 but commonly they are found at the 

 depth of eight feet or more from the 

 furface of the ground, on digging wells and 

 the like. Mr. HeJJelius 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 laft rubbed them ftill finer in the ufuai 

 way, and this afforded him a fine reddifh- 

 brown colour. 



Few black pebbles are found in this pro- 

 vince, which on the other hand yields ma- 

 ny kinds of marble, efpecially a white one, 

 with pale-grey bluijh fpots, which is found 

 in a quarry at the diflance of a few Englijh 

 miles from Philadelphia, and is very good 



F 2 for 



