370 Mineral Caoutchouc. 
6. Mineral Caoutchouc. 
_ This remarkable mineral, hitherto nearly or quite ou 
to the Owdin mine at Castleton, i in Derbyshire, has been 
céently found at Southbury, twenty m thiles N. W. of me 
Haven. This region is a secondary trap basin (see Vol. Il 
pa. 231 of this Souraad) and although only six or eight miles 
in diameter, it presents all the characteristics of the great 
trap region of Connecticut and Massachusetts described by 
Mr. Hitchcock. Among other things, it contains slaty rocks 
with bituminous minerals; these have induced a research 
for coal which is now going on. We understand that they 
find bituminous slate or shale with small veins of coal. Spe- 
cimens confirming this statement are now on the table, and 
they exhibit fibrous limestone, forming very distinct veins, 
or rather layers, running parallel with, and lying between 
those of the aoe The fibres of the satin spar or fibrous 
limestone, are one inch and more in length; they are often 
cracked in the ditecio’ of the fibres and between them 
there are veins occupied by the mineral caoutchouc. It 
has but little elasticity, it is soft, easily. impressible by the 
nail, and compressible between the a es ae otassium, 
and: can be formed into a perfect ball; our is jet 
black; some varieties of it are a little ie far have a re-. 
sinous and splendent lustre, and a flat conchoidal fracture; 
it burns with extreme brilliancy with much black smoke 
and an odour between that of a bitumen and that of an aro- 
pines: during the combustion, drops of liquid fire fall in a 
ream, or in quick succession, and with a whizzing noise 
Seactty like the vegetable caoutchouc and it melts precise- 
ly as that substance does. Rubbed on paper it leaves a 
black streak and acquires a high polish, it does not remove 
pencil marks from paper. The veins containing this min- 
eral are about one quarter of an inch wide and several inch- 
es long.—Ed. 
as 10, 1823. 
td bapa a0 lest his readers 
shoul intra in jury: from ntemptig the mcpitinnacte: are a few ty- 
ical errors; the most important which we observed is, is, that hydrogen 
po 
Fy as the basis of nitric acide (p. 21.) We do not observe any table of 
errata. ‘I his little work cannot fail to be very useful in mares and to pri- 
vate experimenters, and contains a great deal ina small c 
