490 Chronicles of Science. [July, 
surface of the earth, a temperature of 4,600° would be required at the 
depth of 100 miles. ‘“ Reasoning from these facts, we came to the con- 
clusion that the earth’s nucleus, under the enormous pressure to which 
it is subjected, may not be fluid but solid, or probably in a semi-fluid 
state.” 
In the Swiney Lectures on Geology, recently delivered by Dr. 
Perey in the Theatre of the Royal School of Mines,* the lecturer 
states, that there are many difficulties which have always stood in the 
way of receiving the hypothesis that granite is an igneous rock, 
** difficulties” known, at all events, to those who have been accustomed 
to make experiments on the fusion of minerals at high temperatures. 
This is especially seen by examining the condition of quartz; it is 
always found in the crystalline condition, and has invariably a spe- 
cific gravity of 2°6. There is not a single instance known to the con- 
trary. Hence there is reason to believe that the quartz never could 
have been fused, for the moment silica is fused, no matter in what 
condition it was previously, a peculiar glass-like colloidal mass is pro- 
duced, having a specific gravity, which never exceeds 2:3. Therefore, 
there is good reason to conclude that granite could never have been 
formed under the condition of a high temperature. 
Rammelsberg has recently presented to the Physico-Mathematical 
class of the Berlin Academy of Sciences a memoir upon the combi- 
nations of the oxide of lead and titanic acid which are found native. 
Some very fine examples of the mineral vanadinite had been ob- 
tained from Windiskappel, in Carinthia. 
We find an extensive examination of the vanadium minerals 
has been made by Czudnowicz.t He shows that the determination of 
vanadiec acid in the rhom/ic vanadinite from Carinthia is incorrect, and 
the conclusions that the mineral was a simple vanadate of lead is not 
justified. His analyses show it to be a ter-basic vanadate of lead and 
zine. 
e the granite of the Island of Elba, associated with beryl, tour- 
maline, and quartz, two substances were found long since, to which 
the names of Castor and Pollux were given. These minerals were - 
described by Breithaupt, and subsequently examined by Plattner. On 
the authority of this analysis Gmelin says, ‘ Pollux appears to contain 
a larger quantity of alkali than any other known silicate mineral.” It 
has now been more closely examined by M. Felix Pisani, and the 
results obtained by this chemist have been communicated by Henri 
Sainte Claire Deville to the Academy of Sciences of Paris. The 
analyses of Plattner and Pisani agree very nearly as far as the silica 
and alumina are concerned. In place, however, of the potash and 
* These lectures have been most satisfactorily reported in the ‘Chemical 
News.’ 
+ ‘ Poggendorff’s Annalen,’ vol. cxx. 
+ ‘Revue Universelle des Mines, de la Meétallurgie, des Travaux Publics, des 
Sciences et des Arts—appliqués & I’Industrie,’ sous la direction de M. Ch. de 
Cuyper. This journal contains several valuable papers on mineralogy, metallurgy, 
and mining, with notices of the allied science geology, and of the applications of 
science to manufacture. We shall, from time to time, avail ourselves of the useful 
matter which this journal may communicate. 
