102 
THIS GKOLOaiST. 
It is a curious but well-known fact that substances which do not 
possess a crystalline structure may be made to take it under the 
influence of mechanical forces ; thus, iron becomes crystalline by 
repeated percussion, and above wc have an example of a crystalline 
struct)ire being given by pressure. The foregoing facts will also tend 
to explain why coal sometimes takes the form of hexagonal jjrisms in 
contact with trap-rock. The rhombohedron and the hexagonal prisms 
are certainly the crystalline forms of carbon in the state of coal and 
graphite ; whilst the diamond, as is well known, crystallizes iu forms 
derived from the cube or tlie regular octahedron ; whence carbon is 
. dimorphous. 
M. Wohler, Professor of Chemistry in the University of Gottingen, 
has sent to the Academy of Sciences at Paris the following description 
of the composition of a meteoric stone : — 
'• I have just made the analysis of a meteoric stone which fell at 
Kuba in Hungary on the 15th of April, 1857. The aerolite iu 
question is black, and its colour is owing to amorphous coal. It also 
contains — besides those elements generally found in meteorites — a 
certain quantity of organic matter, that is to say, a carburet of hy- 
drogen similar to paraffine, to cozokerite, or to scheererite. The quan- 
tity of this bituminous matter is certainly very small ; but I have 
assured myself of its presence by the most incontestable proofs. This 
organic matter is soluble in alcohol, and becomes cai-bonized by calci- 
nation. I liave since found the same organic matter in the meteoric 
stone which fell in 1838 at the Capo of Good Hope. This stone is 
also of a black colour, and contains 1'5 per cent, of carbon. It is 
probable that this bituminous matter is a product of organic nature, 
and that the presence of coal in these meteoric stones is to be attri- 
buted to the action of heat upon the bituminous matter whilst the 
meteorite was in an incandescent state, i. e. during its passage through 
the terrestrial atmosphere." 
This remarkable discovery, which we have given in the author's 
own words, would appear to be favourable to those philosophers who 
still look upon meteoi ic stones as products of our earth. We should 
not, however, without reluctance abandon anotlier opinion : — When 
the periodicity of remarkable -falls of aerolites became tolerably cer- 
tain, Arago, in 1839, wrote : "We thus become more and more con- 
firmed iu the belief that there exists a zone composed of millions of 
small bodies, the orbits of which cut the plane of the ecliptic at about 
the point which our earth annually occupies between the 11th and 
13th of November; it is a new planetary world beginning to be 
revealed to us." {Annuaire, 1839.) 
It is now almost doubtless that there are other periods besides the 
November one. 
Sir Isaac Newton once said that he took all the planets to be com- 
posed of the same matter as the earth, namely, earth, water, and 
stone, but variously concocted. " Recalling to mind the remarkable 
interview between Newton and Conduit at Kensington," says Alex. 
