508 
POPULAR SCIENCE REVIEW. 
spontaneous cow- or horse-pox at will, simply by introducing the virus into- 
the lymphatics instead of into the blood-vessels. 
Absorptive Power of the Shin. — In the earlier numbers of this journal, 
numerous abstracts will be found of papers on this subject, but now we have 
to hand the statements which have recently been formulated by M. Scoutetten. 
These are : — (1) The rapidity of absorption depends on the tenuity of the 
moelcules of the substance applied and its facility of mixing with the fatty 
secretion of the skin. (2) Gases traverse the pores of the skin with great 
rapidity. (3) Liquids which pass easily into the gaseous state are quickly 
absorbed. Such liquids are : — ether, chloroform, essential oils, benzoin, and 
turpentine. (4) Solid bodies susceptible of volatilization also penetrate the 
skin rapidly : such are — camphor, musk, castoreum, &c. : cantharides is 
absorbed because of its essential oil — cantharadine, which may be volatilized. 
(5) The solid bodies, non-volatile, require to be mixed with fatty or oily sub- 
stances, and to be applied with friction. They thus unite with the natural 
fatty matter of the sebaceous glands, and become absorbed. — Vide The Lancet, 
Record of Medical Science , July 7th. 
METALLURGY, MINERALOGY, AND MINING. 
The Origin of Diamonds. — A curious, and it seems to us very improbable, 
theory of the origin of diamonds was put forward by M. Chancourtois in an 
essay published in the Comptes Rendus for June 25th. The author tries to 
show in this that diamonds have been produced by an incomplete oxidation 
of the carbides of hydrogen, in pretty much the same fashion as the sulphur 
of the Solfatara , described by Professor Ansted in one of our late numbers, 
results from an incomplete oxidation of sulphuretted hydrogen, all of whose 
hydrogen is converted into water, while only a part of the sulphur is changed 
into sulphurous acid. It is by a similar process that petroleum has given 
rise to bitumen, and this again to graphite. “ If, then,” says the author, “ a 
mixture of hydrocarbon gases and vapour of water be submitted to slow 
oxidation, diamonds may possibly be obtained.” It is even possible, he 
observes, that the tubes which convey common coal gas along the streets of 
Paris may contain such artificial diamonds in abundance. 
A curious Lode in a Cornish Mine. — It appears from a paper read by 
Mr. C. Le Neve Foster, at the British Association meeting, that the lode 
described by him is to be seen in New Rose Warne Mine at Gwinear. The 
lode is remarkable from the circumstance that it contains a large quantity 
of rounded pebbles. From an examination of the vein, Mr. Foster concludes 
that there were six distinct periods occupied in its formation. The several 
deposits show a gradual change from pure subsulphate of copper to copper 
pyrites ; in fact, it would seem that at one time the mine consisted entirely 
of copper pyrites, and that the sesquisulphide of iron was being gradually 
