



Chemistry and Physics. 427 



those now described have one common origin and cause. He then 

 considers Plucker's results in relation to those which he formerly ob- 

 tained with heavy optical glass and many other bodies. In conclusion 

 he remarks, " how rapidly the knowledge of molecular forces grows 

 upon us, and how strikingly every investigation tends to develop more 

 and more their importance and their extreme attraction as an object of 

 study. A few years ago magnetism was to us an occult power . Peel- 

 ing only a few bodies ; now it is found to influence all bodies, and to 

 possess the most intimate relations with electricity, heat, chemical ac- 

 tion, light, crystallization, and, through it, with the forces concerned in 

 cohesion ; and we may, in the present state of things, well feel urged 

 to continue in our labors, encouraged by the hope of bringing it into a 

 bond of union with gravity itself." 



2. Method of obtaining crystalline combinations by Heat, and of re- 

 producing- thereby various mineral species; by M. Ebelman, (Comptes 

 Rendus de PAcad. des Sci., t. xxv, pp. 279 and 661; Annuaire de 



j Chemie, 1848, p. 141.) — It is known that borax, boracic acid, phos- 



j phoric acid, and the alkaline phosphates, dissolve metallic oxyds with 



ease, at a certain temperature, and abandon them at a much higher 

 temperature by virtue of their volatility. These bodies enjoy, there- 

 fore, in regard to the oxyds which they hold in solution, the function 

 which water possesses at the ordinary temperature, or at temperatures 

 more elevated in relation to bodies held in solution Uy it, — that very 

 often on evaporating it leaves such bodies in a crystalline condition. 

 This simple principle has led M. Ebelman to a method which will 

 enrich chemistry by the dry method, with a great number of novel 

 combinations, and which will establish the most intimate connection be- 

 tween mineralogy and chemistry. On miflgling together, for example, 

 alumina and magnesia in a little larger proportion than they exist in 

 pinel, with a portion of fused boracic acid, and exposing the mixture to 

 the most elevated temperature of a porcelain furnace, octahedrons are 



.... . .- i n ■ i rTM 



obtained which possess the composition and properties of spinel. These 

 crystals are rose-red or blue according as the oxyd of chrome or of co- 

 balt is used. M. Ebelman has obtained in this way chrysoberyl Al 2 O a , 

 Gl O, and many other aluminates. He has obtained the compound 

 Cr 2 6 3 -f-MgO, crystallized in regular octahedrons. He has prepared 

 many varieties of chrome iron which all present regular octahedrons 

 with the usual mineralogical characters ; in their composition they 





approach spinel and the compound Cr Mg. 



By the aid of this process, M. Ebelman has also obtained the emerald 



and peridot crystallized. 



Boracic acid is too volatile to aid in crystallizing alumina, and in this 

 case he employed borax. By the addition of a little oxyd of chrome, 

 crystals of red ruby are obtained, having the formula of transparent 



corundum. 



3. Researches upon Wax; by Benjamin Collins Brodie, (Philos. 



Mag. for Sept. and Nov., 1848, from the Phil. Trans.)— This research 

 has settled a hitherto disputed subject in a most satisfactory manner, 

 and the care exhibited in the processes employed and the analytical 

 results entitle it to great confidence. 





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