182 Scientific Intelligence. 



He has likewise detected its presence in the ashes of some animals, espe- 

 cially in those of the Janthina violacea, one of the testaceous mollusca. 



From the circumstance of brome being intermediate between chlorine 

 and iodine in some of its more important chemical relations, M. Balard 

 at first suspected it to be some unknown compound of these bodies ; but 

 as, on further examination, he failed in obtaining the least trace of de- 

 composition, he was induced to adopt the opinion that it is an elementary 

 substance. The facts which have been related are greatly in favour of 

 this view. They have not, however, as yet, been confirmed by other che- 

 mists, and therefore it would be premature to form a decided opinion on 

 the subject. We may observe, however, that MM. Vauquelin, Thenard, 

 and Gay-Lussac, in their report to the Parisian Academy of Sciences, 

 speak in the most flattering terms of the memoir of M. Balard, and re- 

 gard his opinion as highly probable, though they express themselves in a 

 very guarded manner. 



'ill. NATURAL HISTORY. 

 MINERALOGY. 



12. Thenardite, a new mineral species. — The mineralogical characters of 

 this substance were ascertained by M. Cordier, from specimens sent to him 

 for the purpose by Professor J. L. Casaseca of Madrid, a pupil of M. The- 

 nard, in compliment to whom it is denominated. According to M. Cordier, 

 it possesses the following characters. Form, a scalene four-sided pyramid, 

 whose base is a rhomb of nearly 125° and 55°, the ratio between the axis 

 and a side of this rhomb being = 7.3 nearly. Crystals frequently have 

 the apex of the pyramid taken off by a plane. It cleaves readily in a. direc- 

 tion perpendicular to the axis of this pyramid, and likewise parallel to planes 

 replacing its lateral edges. It is not transparent, and its specific gravity ap- 

 proaches to that of glauberite, which is 2.73. 



From the details given by M. Casaseca, it appears that Thenardite is one 

 of those substances, whose formation and decomposition is continually go- 

 ing on in the grand chemical laboratory of nature, and which hence forms one 

 of those links by which minerals, commonly so called, are connected with 

 the substances produced by nature with the assistance of chemical art, and 

 arbitrarily excluded in the usual definitions from the mineral kingdom. 

 It was dicovered nearly nine years ago by M. Rodas five leagues from Ma- 

 drid, and two and a half from Aranjuez, in a place called the salt-mines of 

 Espartines, and considered by him as a sulphate of soda, mixed with a 

 small quantity of subcarbonate of soda. During the winter season water 

 impregnated with particles of the salt exudes from the sides and the bottom 

 of a hollow, and when sufficiently concentrated, it deposits part of its con- 

 tents in more or less regularly formed crystals. Mr Casaseca states, that, 

 when exposed to the action of the atmosphere, it is changed into powder, 

 the change beginning from the surface, upon which the powder forms a coat- 

 ing. This is not however owing to the same cause upon which de- 

 pends the decomposition of common glauber-salt, which loses water, 

 whereas Thenardite attracts a portion of it, and forms a hydrous salt, 



