SCIENTIFIC SUMMARY. 
205 
of antimony and the boiling point of cadmium. — Vide Chemical NewSy 
March 5. 
The Mode of Formation of Precious Stones. — One of the most interesting 
papers presented for some time to the Eoyal Society is that which appears 
in the number of the Pi'oceedings just issued, and which was read on 
February 18 by Mr. H. C. Sorby. It deals with the natural structure of 
the different precious stones, and it leads to the following conclusion : On 
the whole, the various facts seem to show that ruby, sapphire, spinel, and 
emerald were formed at a moderately high temperature, under so great a 
pressure that water might be present in a liquid state. The whole structure 
of diamond is so peculiar that it can scarcely be looked upon as positive 
evidence of a high temperature, though not at all opposed to that supposi- 
tion. The absence of fluid-cavities containing water or a saline solution 
does not by any means prove that water was entirely absent, because the 
fact of its becoming enclosed in crystals depends so much on their nature. 
At the same time the occurrence of fluid-cavities containing what seems to 
be merely liquid carbonic acid, is scarcely reconcilable with the presence of 
more than a very little water in either a liquid or gaseous form. “ We may 
here say that we do not agree with those authors who maintain that the 
curved or irregular form of the fluid-cavities is proof of the minerals having 
been in a soft state, since analogous facts are seen in the case of crystals 
deposited from solution.” 
METEOROLOGY. 
The Mean Temperature of the Superficial Structure of the Earth has 
formed the subject of a communication to the French Academy by M. 
Becquerel. The paper contains too many details for a full abstract, but 
some of its conclusions are of interest. If, says the author, we take the mean 
of flve years, which is the most rational method, we deduce the following 
inferences : — I. The mean temperature presents but slight variations from 
6 to 21 metres, and from 21 to 26 metres. 2. From I to 36 metres the diffe- 
rence has been from I°-36. But if it is demonstrated that during the five years 
the mean temperatures have been sensibly the same from 6 to 21 metres, it does 
not necessarily follow that the temperature at these various points has been 
stationary. To establish a rule in the matter, we must investigate the varia- 
tions of temperature in the course of the year, according to the seasons ; that is 
to say, the differences between the mean, annual, maxima, and minima. The 
variations decrease to 21 metres, where they are nil; at 26 metres the 
variation is half a degree 5 then up to 36 metres there is no variation. 
Thus all the earth strata have a constant temperature at 21, 31, or 36 
metres. Where, then, shall we place the stratum of invariable temperature ? 
Is it at 21, at 31, or at 36 metres ? Or might we not find it still lower, if 
we could extend our observations beyond this point ? 
A New Anemometer, which costs less than other forms and is both 
accurate and durable, has been described by Mr. W. Oxley at the meeting 
of the Manchester Literary and Scientific Society (February 2). The 
