Intelligence and Miscellaneous Articles. 231 



Society, which I inclose for insertion in the Philosophical Magazine, 

 if you think they would prove of sufficient interest to your readers. 

 2 Park Terrace, Highbury, I am, dear Sir, yours truly, 



August 17, 1844. E. F. Teschemacher. 



MINERALOGICAL NOTICES. BY J. E. TESCHEMACHER, ESQ. 



Glauberite, brought from Tarapaca, Peru, by Mr. John H. Blake. 



This mineral is found in small crystals, which are imbedded in a 

 beautiful, silky, fibrous borate of lime, published in Alger's edition 

 of PhilUp's Mineralogy under the name of Hayesine. 



This glauberite was analysed by A. A. Hayes, and found to contain 



Sulphuric acid 57-220 



Soda 21-324 



Lome 20-680 



Iron -444 



It is essentially a compound of sulphate of lime and sulphate of soda. 

 The first crystals I measured, the figure and measurements of which 

 are in the last edition of Dana's Mineralogy, were extremely dull, 

 so that I could only consider them as approximative. Mr. Hayes 

 afterwards sent me some extremely brilliant crystals, the measure- 

 ments of which coincided exactly with those of the glauberite from 

 Villa Rubia in Spain. The figure above named is that of the first 

 crystals I found. Subsequently others came to light, of very diiFer- 

 ent forms, produced by other modifications. 



It is stated in Dana, that if crystals of glauberite are left in water, 

 they will at length fall to pieces. This is probably true. Those 

 from Tarapaca, if treated carefully with cold water, will permit 

 nearly all the sulphate of soda to be dissolved out, leaving the form 

 of the crystal unaltered, and the edges as sharp as ever. Their ap- 

 pearance before the microscope, after the loss of the sulphate of soda, 

 is that of snowy- white, fine granular sulphate of lime (alabaster). 

 From 15 grains of this glauberite I have obtained 6^ grains anhy- 

 drous sulphate of soda, and do not doubt that the whole quantity 

 might with care be extracted. If some forms of these alabaster 

 crystals had been first found and analysed, they would have been 

 pronounced to be pseudomorphous forms of an unknown mineral, of 

 which sulphate of lime had taken the place. 



Now, if the action of the solvent powers of various chemical so- 

 lutions, as well as those of the gases which can be held by water, 

 be studied with care, the natural decomposition of many minerals, 

 as well as their replacement by other substances, in what are called 

 pseudomorphous forms, will be very much illustrated. 



Pyrrhite. 



Prof. J. W. Webster, of Harvard University, has lately returned 

 from the Azores, and brought with him some interesting minerals, 

 several of which he has most kindly placed in my hands ; amongst 

 others, a beautiful arragonite, at first sight much resembling the 

 needlestone. 



He also favoured me with two small specimens of a felspathic 



