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Magnesium, Boron, Aluminium. — Photogj-aphy, 2G1 



Magnesium^^ Boron, Aluminiitm. — We o^ye to M. R StClaire 

 Deville a series of facts of great interest, to "whicli we can here 

 only allude. 



^ Magnesium is volatile like zinc, and may be as easily dis- 

 tilled; it also fases at the same temperature, and burns with a 

 bright flame, in the midst of which some points of indigo blue 

 may be distinguished ; at the same time it disengages a white 

 cotton-like oxyd, like that of zinc, which is fixed and infusible. 

 These arc but a few points from the researches of Deville and 

 Caron, at the laboratory of the Normal School 



The results respecting horon are communicated by Deville and 

 Wohler. Wdhler recently visited Paris to compare his results 

 with those of Deville. It appears that crystallized boron is akin 

 to the diamond ; it has very nearly its hardness, and may be of 

 great use when hard stones are wanted in watch or clock mak- 

 ing, or their powder for grinding, especially grinding glass. 

 Crystallized boron is obtained by reducing boric acid by means 

 f of aluminium ; it forms borate of alumina and boruret of alu- 



* minium, and from the latter at a lower temperature boron sepa- 



rates, just as graphite in the cooling of fused iron. 



Waters of Artesian Wells.-— On examining the waters of the 

 Artesian well of Grenelle with reference to the gases present, M. 

 Peligot has ascertained that they contain not the least trace of 

 air. Subterranean waters ought therefore to be aerated before 

 being used as an aliment, and accordingly they are about to con- 

 struct at Grenelle a species of tower, from the top of which the 

 water will descend in innumerable threads, so as to present as 

 i^uch surface as possible to the air. 



Photography, The regular Universal Exhibition ly tJie French 

 Photographic Society. — This exhibition is open and is remarkable 

 for the magnificent display of pictures it affords : and they are 

 numerous in spite of the severity of the jury of admission. All 



the processes are 

 collodion, including 



represented, from the Daguerrian plate to diy 

 ing moist collodion, albumen, albuminized col- 



lodion, waxed paper, chloridized albimien, etc., with all the 

 methods of fixing pictures employed, and all kinds of photo- 

 graphy. . There are portraits, landscapes, buildings, panoramic 

 views, etc. Only photographs from living nude subjects, callecJ 



^Academies," are excluded. 



The arrangement of the pictures is according to the nations 

 contributing them. Visitors stop in crowds before the photo- 

 gal vanogTaphs exhibited by M. Pretsch, representing objects such 

 as the Yenus of Milo, the Cathedral of Strasburg, with a finish, 

 ^nd beauty which would make ns believe that they had been 

 touched up with a graver, if men of truth had not on their honor 

 affirmed the contrary. • 



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