Foreign Literature and Science. 18S 



These analyses prove the chrysolite and olivine to be iden- 

 tical. The presence of oxide of nickel in these minerals is 

 remarkable, and has never before been detected ; it appears 

 to exist in all the specimens which occur in volcanic rocks, 

 for M. Stromeyer has found it in those of Vesuvius, of Au- 

 vergne, of Eifel, and of Itabichtswalde, while, to the contrary, 

 it is wanting in the olivine of meteoric stones. 



The mineral of Grimmoe differs totally from olivine and 

 chrysolite in its composition. — Annales des Mines, Tome XII. 

 1826. 



41. Anhydrous Sulphate of Soda. — Dr. Thomson has dis- 

 covered the existence of an anhydrous sulphate of soda. It oc- 

 curred in a manufactory of carbonate of soda at Glasgow, 

 where the process consisted in mutually decomposing proto- 

 sulphate of iron and common salt. The sulphate of soda 

 thus produced is decomposed and converted into carbonate 

 of soda in the usual manner. They were formerly in the habit 

 of boiling their saturated leys, during which part of the pro- 

 cess, large crystals were observed to form on the inside of the 

 boilers ; these crystals are the anhydrous salt, their form is 

 that of an octohedron with a rhombic base, they are translu- 

 cent, firm and solid in their texture, and of a glassy appear- 

 ance. 



Thus it is ascertained, that sulphuric acid and soda are ca- 

 pable of combining and crystallising without water, as well 

 as sulphuric acid and potash. Three distinct species of sul- 

 phate of soda are now known to exist. 



1. Anhydrous sulphate, crystallising in a boiling solution, 

 in the form of an octohedron with a rhombic base. 



2. Common sulphate of soda, containing ten atoms water, 

 crystallising in a cold solution, and forming crystals which 

 have the shape of doubly oblique four-sided prisms. 



3. Sulphate of soda, crystallising in a supersaturated solu- 

 tion of sulphate of soda, made in a high temperature, and set 

 aside for some days in a well corked phial, the crystals are 

 opaque, white, four sided prisms, and contain eight atoms of 

 water instead often. — Annals of Philosophy. Dec. 1826. 



42. Identity of Epistilbite and Heidandite. — It is extreme- 

 ly probable that epistilbite is identical with heulandite. Dr. 

 Rose who described epistilbite, was led to regard it as a dis- 

 tinct species, chiefly in consequence of its difference from the 



Vol. XIII.— No. 1. 24 



