1865.] 



Mining, Mineralogy, and Metallurgy. 



489 



quantities in the district of Estraraadura, in the South of Spain, has 

 been recently analyzed by Dr. Forbes, F.E.S. The specimens re- 

 ceived, though in large blocks, consisted of pure phosphorite, appa- 

 rently unaccompanied by any other minerals ; the mineral itself was 

 massive, and, on breaking, the fracture was uneven and earthy, dis- 

 closing a slightly radiating dendritic structure, but no trace whatever 

 of crystallization. The colour of fresh fracture was chalk-white, but 

 weathered surfaces frequently showed a dirty or rusty white colour 

 externally. Lustre earthy ; opaque ; streak and powder dead white. 

 Hardness about 4*5. The specific gravity was taken on two distinct 

 specimens, and found to be 3*00 and 2-92 respectively at 60° Fahr. 

 The result of a very careful analysis gave the following composition : — 



Fluoride of Calcium 











8-01 



Chloride of Calcium 









0-16 



Lime 









41-03 



Magnesia 











0-12 



Alumina 











1-75 



Sesquioxide of Iron 





( 







1-19 



Phosphoric Acid 











44-12 



Sulphuric Acid 











trace. 



Carbonic Acid 











0-40 



Insoluble matter 











1-41 



Water . 











1-44 



Total 99-63 



I 



ilETA 



LLTJR< 



3Y. 







M. Pastera, Chemist of the Department of Mines and Works, has 

 been experimenting at Vienna on some new processes for the extrac- 

 tion of the gold disseminated in argentiferous minerals. Each metal 

 is extracted separately — the gold by chlorine water, and the silver by 

 a solution of salt, or by hot water after the silver has been converted 

 into a sulphate by a roasting process. M. Pastera, after having made 

 his first experiments on a small scale, proceeded to treat the roasted 

 ores from Nagyag, in Transylvania, and he obtained the most com- 

 plete success.* 



Attention has again been drawn to the question, whether the 

 molecular condition of metals, especially iron and steel, alters by 

 continued vibrations or repeated percussion. 



At a recent discussion on the Submarine Atlantic Cable, the 

 liability to this alteration was insisted on as though it were a proved 

 fact,"}" and in an established periodical,^ it is implied that Mr. 

 Sorby's microscopic researches have established the fact. It should 

 be clearly understood by all, that there are not any experiments which 

 confirm this statement, although there are many which at first appear 

 to prove its correctness. Mr. Brunei showed that the same piece of 

 go od iron might be broken with either a fibrous or a crystalline struc- 



* Institut Imperial de Geologie, Vienna. 



t 'Phil. Mag.,' May, p. 340. 



% ' Society of Arts Journal,' May 12, 1865. 



