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FOREIGN CORRESPONDENCE. 



By De. T. L. Phipson, of Paris. 



Dauhree's researches on recently -formed Minerals — -Action of Mineral 

 Waters upon old Roman Cement — Daily production of Zeolites , Fluor- 

 Sjmr, Arragonite, ^'c. — Plomlierite — Time an importayit element in 

 Geological Experiments — Delesse on the Metamorphism of Argillaceous 

 and Siliceous Rocks — Earthquakes at the Cape of Good Sope — Appari- 

 tion of different kinds of Fish after violent Farthguakes. 



Professor Daubree, of Strasburg, has obliged us with a copy of his 

 interesting Memoir on the Mineral Deposits of the Thermal Springs of 

 Plombieres." We hasten to make known to our readers the important 

 results contained in this new work. 



The investigations already made concerning the natural beds of those 

 minerals, which have been classed in the family of Zeolites,"^' have led 

 mineralogists to believe that water has been active in their formation. 

 "We have already shown f how M. Daubree has reproduced in his 

 laboratory a certain number of Silicates, and how he discovered that 

 they had been formed in certain springs at Plombieres since the time of 

 the Romans. The present Memoir completes our knowledge of these 

 interesting phenomena — and what can be more interesting than the 

 formation of a stone before our eyes ! It appears, moreover, that Zeo- 

 lites have rarely or ever been artificially produced, and their origin 

 has always been more or less enveloped in mystery. 



In order to augment the volume of water in the warm springs of 

 Plombieres, the author has been constructing a deep aquaduct, for which 

 it was necessary to cut through a crust of cement which the Romans 

 formerly spread over the valley where the springs rise. This cement 

 is composed of fragments of bricks, variegated sandstone, and lime. It 

 has been powerfully acted upon by the mineral waters which come in 

 contact with it at a temperature ranging from 50 to 60 degrees 

 (centigrade). The lime and the bricks themselves have been thus 

 transformed into new combinations, which have crystallised in their 

 cavities. Among the products of this transformation, the most frequent 

 are certain Zeolites, and especially Chahasite and Apophyllite. The 

 former, which is a silicate of alumina and lime, is generally found in 

 the spilites of certain basalt formations, in the Tyrol, Bohemia, the 

 Hebrides, &c. ; the latter, a silicate of lime and potash, is seen also in 

 the cavities of spilite rocks and in the beds of magnetic ironstone in 

 Norway, Sweden, &c. The samples taken from the warm springs of 

 Plombieres were in perfect, well-defined crystals, and in every respect 

 similar to the minerals from the above-named countries. 



Besides these, many other Zeolites are formed at Plombieres, but their 

 exact species has not yet been accurately ascertained. M. Daubree 

 names, therefore, with uncertainty Scolezite, Harmotome, and Gismondine. 

 He mentions, also, the presence of a probably new species of hydrated 



** Hydrated Silicates, partly soluble in strong acids, — T. L. P. 

 t Vide the Geologist for Feb. , 1858. 



