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Scientific Intelligence. 
lowing as the most distinctive characters of the Newry pitch- 
stone ; its ready divisibility into laminae ; its proneness to_ dis- 
integrate ; the regularity of its rhomboidal fragments, and its 
oily or bituminous smell. The bituminous smell led Mr Knox 
to believe, that the pitchstone contained some inflammable matter ; 
and after a series of experiments, detailed in his memoir, he found, 
that the pitchstone of Arran, Newry and Meissen in Saxony, af- 
forded two inflammable substances; the one more volatile than the 
other, but both inseparable from the stone, except at a heat ap- 
proaching, if not entirely amounting to, whiteness. He conjectures 
it to be a combination of naphtha and nicotine. The following is 
the result of his analysis of the Newry pitchstone : Silica 78.800, 
Alumina 11.500, Lime 1.12, Protoxide of Iron 3.036, So- 
da 2.857, Water and Bitumen 8.500, = 99-813. Professor Ja- 
meson, in his Mineralogy of the Scottish Isles, vol. i. p. 48., says, 
when describing the Arran pitchstone, “ when pounded, it emits 
a bituminous smell , which renders it probable it may contain an 
inflammable matter? The pitchstones mentioned by Kirwan as 
containing inflammable matter, appear to be not true pitchstone, 
but opals. The pitchstone of Planitz in Saxony, like that of Ar- 
ran, we know contains bituminous matter ; and we have speci- 
mens from that quarter, containing a black silky fibrous shining 
substance, which is a compound of silica, carbon, alumina and 
iron. And we may add, that, according to some chemists, the 
pitchstone of Potschappel in Saxony, contains, besides the usual 
ingredients, three parts of Liihion. Mr Knox formed a sub- 
stance resembling pumice, by exposing the pitchstone to the ac- 
tion of heat ; but for the details on this curious subject, we must 
refer to the memoir itself. 
23. Changes in Carrara M arble. —According to Em Ili- 
petti (Giorn. Arcad. xlv. 54.) the marble of Carrara affords an 
example of the chemical change of a mountain rock without 
its disintegrating. The marble rocks of Carrara have not 
every where the pure snow-white colour for which they are 
so famous, but are for the most part greyish-white, and are only 
snow-white in certain parts, where veins and spots of oxide of 
iron, sulphate of iron, and iron-pyrites, have been formed. Some 
of these spots seem to be of old formation, and fixed ; others, 
on the contrary, appear to be forming at present, and are again 
