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that this Stone is in fpecific Gravity to Water as 170 
to 100. 
A Fragment of the greater Stone, which weigh'd 
in Air Gr. 83 ^4 weigh'd in Water of the fame 
Degree of Warmth, Gr, 34 fo that the fpecific 
Gravity of this is the fame as of the other. 
A Quantity of the larger Stone, weighing four 
Ounces, being diddl'd in a coated Retort, yielded 
Gr. 3 7 7^ above 20 Ounces of a firong alcaline Spi- 
rit, of a brown Colour, fuch as is drawn from Hart's- 
horn 5 leaving a black Coal weighing Gr. 74 ts fhort 
of 2 Ounces j Gr. 36^ being converted into Air* 
and otherwife loft in colie&ing the Produce of the 
Diftillation 5 a fmali Quantity of black Oil adher'd to 
the Neck of the Receiver, and a few Drops of this 
Oil appear'd in the Spirit, when it was firft pour'd 
off 5 but, after (landing fome time, fell to the Bot- 
tom in the Form of a black Sediment. 
The black Coal, calcined under a Muffle in a very 
firong Fire, loft but 22 Grains, and became a white 
inlipid Earth. 
A Fragment of the great Stone, which had lain 
expofed to the Air and Weather above twelve Months, 
as mention'd above, weighing in the Air Gr. f8, 
weigh’d in Water Gr. 24f* 0 , after it had flood a 
confiderable Time, that the Water might enter its 
Cavities : So that this Stone, tho' feeming of a loofe 
Texture, came out not much inferior to the other 
in fpecific Gravity 5 this being to Water as 165 to xoo, 
A 
3 
