Scientijic Intelligence . — Chemistry. 383 



13. Combinations and Crystallizations, effected by the action of 

 weak electrical forces. — Let the owners of diamonds be comforted : 

 chemistry and physics do not yet furnish the means of making them. 

 It was thought that by the decomposition of carburet of sulphur, the 

 carbon might be obtained in a crystallized state, that is, in the state 

 of diamond. M. Becquerel has just communicated to the Acade- 

 my of sciences, in its session of 27th of July, the result of several 

 experiments, in which he effected the decomposition of carburet of 

 sulphur by electric action of a low power; but instead of dia- 

 mond, he obtained only carbon in thin plates, very pure it is true^ 

 but of an aspect altogether metallic. 



M. B. disposes his apparatus in two different modes ; sometimes 

 a bent tube, like the letter U, at the bottom of which is placed a wad 

 of amianthus, or preferably of fine sand or argil, to prevent, or at 

 least greatly to retard the mixture of the two different liquids, placed 

 in each branch, and which are united by a homogeneous metallic 

 arc. Sometimes it is a tube closed at one end, at the bottom of 

 which is placed an oxide, or some powdered charcoal, and which is 

 then filled with a conducting fluid, and through which passes a me- 

 tallic rod, touching the substance at the bottom. In either case, an 

 electric current is established. If a solution of sulphate or nitrate of 

 copper be put into one branch of the bent tube, and a solution of 

 common salt into the other, and the connection effected at the top by 

 a bent wire or strip of copper, there will in the course of a long time 

 be found crystals of a double chloride of copper and sodium depos- 

 ited on the end of the copper which dips into the alkaline solution, 

 while the other extremity is covered by degrees with copper. The 

 first extremity is positive, the second negative. In changing the li- 

 quid and the strip of metal, new products are obtained ; and in this 

 way M. Becquerel has enriched chemistry with several new pro- 

 ducts, such as double chlorides, and double sulphurets, Sic, the 

 crystalline forms and chemical composition of which he carefully de- 

 scribes. 



It is by the second apparatus that he obtains metallic oxides in a 

 crystalline form. Protoxide of copper for example, in crystals, is 

 procured by placing in the bottom of the tube, deutoxide of copper, 

 filling the tube with a saturated solution of nitrate of copper, and 

 placing a strip of copper in it so as to touch the deutoxide, and then 

 closing the tube hermetically. In ten days, there are visible on the 

 copper, small cubic crystals of metallic brilliancy, which prove to be 

 protoxide of copper. 



