M. Godon’s mineralogical observations. 14h 
But I observe, that the property of emitting a sound somewhat metal- 
lic appears dependent ingis mineral on a certain degree of cohesion, 
together with its tabular shape, which might be easily obtained by art 
from several other stones. Some thin tables of black marble are im- 
ported from the East Indies, which are used in China instead of bells; 
and even ice itself possesses the same sonorousness, when in large 
plates and condensed by a great degree of frost. Some fragments of 
sonorous péetrosilex are found ae by veins of compact epi- 
dote. 
22, I give the name of jasper-petrosilex to a species, which pre- 
sents a red brown or dark red colour, with but very littletranslucency on 
the edges. ‘This kind, fusible before the blowpipe, sometimes into a 
white enamel, often presents several veins of different shades of red- 
dish [Malden 1] ; sometime#white and red yeins, running parallel 
to each other, in straight or curved lines [Chelsea beack O]. Most 
of the varieties of jasper petrosilex are susceptible of an hign polish, 
From the likeness of the veined jasper-petrosilex with some stones, 
which were used by the ancient Grecks and Romans in making bas- 
‘s0-relievos, called camchuja, we are induced to admit, that most of 
the stones, called antique engraved stones, consist of a mineral of this 
‘Kind. An ingenious naturalist has before observed, that the jasper, 
veined red and green from Siberia, was a petrosilex. 
Some fragments of jasper-petrosilex include often.spots of a fesh 
colour [Milton 1], perfectly analogous to the petrosilex of Carlshakt 
in Sweden. 
23. Petrosilex of a homogeneous texture and a middling hardness, 
when sme ed | conveniently, is susceptible of being used as whet- 
stone. age is found exactly analogous to the Turkey-stone, which, 
as Bened. de Saussure first observed, ought to be considered as be- 
longing to this genus, It is probable that this part of Massachusetts. 
