324 

 J Oh ike Argificicii Formation of Minerals. By HausmAIS N^, 



A' i\n [Artificial Formation of Minerals hy Igneous Action*^ J^^s^m- 

 ■ nbAo fessor Hausmann of Gottingen. . ,• 



- Mitscherlich, many years ago, published important details on this 

 .subject. More lately, Professor Hausmann of 'Gottingen, in an in- 

 teresting Memoir, of which a copy was forwarded to us, gives an ac- 

 count of minerals he observed forming about furnaces, by furnace- 

 action. He enumerates the following : — Silver, lead, copper, iron, 

 bismuth, lead-glance, blende, oxide of zinc, red copper ore, iron- 

 glance, magnetic iron ore, chrysolite, pyroxene, containing alumina, 

 Humboldite, orthoclase, lead-vitriol, and arseniate of nickel. 



Brown, yellow, green, and black blende were observed formed in 

 the furnaces of the Lauten valley in the Hartz, in regular octahe- 

 drons and dodecahedrons ; also, in lamellar and radiated concretions. 

 _ Lead-glance, he informs us, is often formed by sublimations in the 

 ; chimneys of furnaces, and the crystals are cubical with the usual 

 cleavage ; and crystals of magnetic iron sometimes incrust cavities 

 ^^,%.ston^.ov }|ricl^^w(^l^ of tliq,/^ ,,,, , ..,,, ,,, ^ 



-illim ffi-xoYOH aioW ?fi;jgv'io ofli : hhr, oi'xod hafi „Ria&a"pf.frt .^oilla leri. 

 ii'3i8* -Q^i]?'^^ Artifii:ial Formation of Minerals in the Dry^^^^^r 



bo.l(-onfn:t ^ through the agency of Heat. By M. Ebelmen;*,^ ^^,^^:;> 



*^' The method pursued by M. Ebelmen in his investigations, con- 

 sists in dissolving the constituents of the mineral to be formed in an 

 appropriate solvent, and submitting the whole to evaporation at a 

 high temperature in a porcelain furnace. Boric acid was the so)- 

 ■' vent commonly employed, but the author also used borax, phosphoric 

 ' acid, and certain alkaline phosphates and alkalies. Many minerals 

 were formed by this method. Thus of the minerals belonging to the 

 Spinel group several were obtained by the author. The experiments, 

 however, have been repeated, and with better success, as regards the 

 size and perfection of the crystals obtained. 



Magnesian Spinel was prepared, by igniting a mixture of alu- 



■' mina, magnesia, chromate of potash, and boric acid, the mixture re- 



•maining in the furnace eight consecutive days. The crystals thus 



produced were octahedrons, truncated upon the twelve edges ; some 



of them three or four millimetres in the side ; they were transparent, 



of great lustre, and of a more or less marked rose colour. The angles 



' measured perfectly corresponded to the theory ; the density of the 



'^ crystals was 3-542. Gahnite was obtained by a precisely similar 



'■ process in well-defined, white, octahedral crystals, of density 4'68. 



By adding a small quantity of bichromate of potash to the mixture, 



' ruby-red truncated octahedrons were obtained of great beauty and 



