SCIENTIFIC SUMMARY. 
569 
in specimens of each of these minerals. Many years ago he discovered 
cavities in various minerals, some of which contained two fluids, supposed 
to he hydro-carbons, whilst in others there were crystals of various forms. 
In examining minerals by polarized light he has more recently discovered 
“ pressure cavities,” the optical properties of which show that the con- 
taining mineral while in a soft state has been compressed by an elastic 
force proceeding from the cavity. He considers that the existence and 
arrangement of these cavities completes the evidence for the igneous origin 
of the minerals, and of the rocks which contain them. 
Lepidolite. — Several varieties of European lepidolite have furnished the 
new metals rubidium and caesium. Mr. 0. D. Allen, of Yale College, U.S., 
examined specimens of the same mineral from Hebron in Maine, and 
found the new element in comparative abundance. Lepidolite there occurs 
in large quantity in a coarsely crystalline granite, associated with tour- 
maline and albite. Like the lepidolite of Penig, in Saxony, it is also 
associated with the rare species, amblvgonite. The Hebron lepidolite con- 
tains more than three-tenths per cent, of csesium. 
Conversion of Arragonite into Marble. — By heating arragonite in an iron 
crucible made as air-tight as possible, and by heating lithographic stone 
or chalk in a porcelain vessel with a ground stopper, G. Rose and Dr. 
Siemens have succeeded in producing marble. That prepared from arra- 
gonite was especially distinct, and closely resembled Carrara marble. Arra- 
gonite, chalk, lithographic stone, and marble, are all varieties of carbonate 
of lime ; when heated in open vessels they lose carbonic acid, and furnish 
quicklime. 
Sulphur in Corfu. — A communication from the Board of Trade states 
that sulphur has been discovered on the Island of Corfu, and that Professor 
Ansted has expressed his opinion that the vein is of considerable extent 
and value. The Newcastle Chamber of Commerce is seeking for further 
information regarding it. 
Minerals of California. — The total value of the gold obtained from all the 
California mines in 1862 was 42,539,799 dollars. The production of mer- 
cury in the State has attained an enormous extent. Last year the amount 
was 3,025,875 lb. ; most of which was exported. 
Minerals of Australia. — The “ South Australian Register ” informs us 
that Mr. Hargraves has carefully examined Western Australia from King 
George’s Sound to Perth, and has found copper, tin, and silver, but no 
gold. 
Calamine in Tipperary. — Mr. George Darlington has described a remark- 
able deposit of calamine (carbonate of zinc) at silver mines in Tipperary, 
which has been found within the last four years. The result of exploration 
has shown an extensive deposit of this ore, varying from ten to sixty feet 
thick, and covering a known area of several acres. The deposit seems to 
occur between two stratified rocks ; and it yields an ore which averages 
about thirty per cent, of metallic zinc when freed from its accompanying- 
ochre. Probably 100,000 tons of marketable ore have been laid open. 
It is the only deposit of the kind yet discovered in the United Kingdom. 
