690 Chronicles of Science, | Oct., 
This salt may, no doubt, under strong pressure be heated to the melting 
point without losing its carbonic acid; this is a laboratory experiment 
often cited by the Plutonists; but it is quite a different thing with a mix- 
ture of carbon and carbonate of lime at a high temperature. If we reject 
the Neptunian origin of granulated limestone, we must then, as with crys- 
talline rocks, suppose that graphite has been introduced by the wet way 
at a more recent period. The same remark applies to magnetic pyrites 
(sulphide of iron) often very rich in plumbago kerns. Does graphite, like 
all carbon, belong to the organic kingdom? It is certain that anthracite, 
lignite, coal, are the result of the slow decomposition of an enormous 
quantity of vegetables. The impressions found on them often indicate 
the kind of vegetables, most of them extinct, which have contributed to 
these carbonaceous formations. Graphite, if not formed in precisely the 
same way as coal and anthracite, nevertheless bears signs of an organic 
origin. The formation of nuclei and veins of graphite in crystalline rocks 
is sufficiently explained by the decomposition of carbonized hydrogen gas 
at a high temperature; this gas, disengaged from organic matters, and 
penetrating the fissures of the burning rock, would undergo decomposition 
into hydrogen and carbon. 
“It is this deposited carbon which forms graphite. If in our labora- 
tories we do not obtain exactly the same product, it must be remembered 
that nature has means at her command which escape our researches. We 
find it impossible to make coal from wood. The wood may be carbonized 
by the dry or by the wet way. In the first case the carbonization is very 
rapid; in the latter it is extremely slow, as is shown by the blackened 
points of piling sunk in water. Finally, graphite has been found in me- 
teorites or aérolites. Attempts have been made to explain its presence 
here by the continuance of these stones in soil more or less rich in ¢ar- 
bonized principles. But with regard to newly-fallen stones, this explana- 
tion is inadmissible. If it be maintained that graphite is an organic 
product, it must be admitted that in the case of newly-fallen meteorites 
it can proceed only from organic matters belonging to another world 
than our own.” 
A very interesting account of the mode of occurrence of the 
emeralds of Salsburg has been lately communicated to the Imperial 
Institute of Geology at Vienna, by M. Lipold. These emeralds are 
found in the valley of Habach, in the district of Haut-Pinzgau. The 
locality in which they are discovered is 2.212 metres (of rather more 
than 39 inches) above the level of the Adriatic. These emeralds are 
cemented in a mica schist which is regularly bedded in the great system 
of the crystalline schists of the central Alps, passing on one side into 
a talcose schist, and on the other to a very fine grained gneiss, rich in 
mica. In each of those the emeralds are found inclosed. The bed of 
emeralds has been opened upon for the length of 227 metres, with a 
thickness of from 2 to 4 metres. These emeralds have usually the form 
of prisms with six faces, and are cither of a deep dark-green, or of an 
apple-green colour. Stones of a fine green colour and free from flaws 
are rare. The largest which have yet been found have been about 13 
centimetres (the English inch is about 24 centimetres) in thickness 
and 52 centimetres in length. 
M. Henri Ste. Claire Deville communicated to the Académie des 
Sciences a ncte from M. Weehler, in which he relates some experiments 
which appear to show that M. Lewy was not quite correct in stating 
