636 SCIENTIFIC RECORD FOR 18?3. 



line plates the formula Al B 6 and to the yellow octahedra the formula 

 C 2 AljB 24 . These discrepancies hare led to an examination of the sub- 

 ject by A. Joly, who states that at the elevated temperature used by 

 Deville and Wohler only very small quantities of the large black plates 

 wore obtained, but at a lower temperature, with small quantities of 

 material, smaller black crystals united to the yellow ones are formed. 

 It is this substance that Deville and Wohler probably analyzed, while 

 Hampe reduced boric acid in clay crucibles at a much lower temper- 

 ature and obtained large black crystals containing but little carbon. 

 Joly also finds that the yellow crystals A1B 6 dissolve readily in boiling 

 nitric acid without a residue, but the brown or black crystals obtained 

 at a high temperature leave a carbonaceous residue when treated with 

 the same oxidizing agent. The products of the reduction of boric acid 

 by aluminium therefore embrace : 



(1) A1B, yellow hexagonal plates. 



(2) A1B 6 , large black crystalline scales. 



(3) Yellow cubical crystals containing Al and C. 



(4) Several compounds of carbon and boron not further character- 

 ized. (Comptes rendus, icvii, 45G.) 



Hydrated Carbon Disulphide. — All who have worked with carbon 

 disulphide are familiar with the peculiar cauliflower like growth of a 

 snow-white substance which forms when the volatile liquid is filtered 

 or otherwise exposed to rapid evaporation. Berthelot, Wartha, Ballo, 

 and others, have studied this substance, and the latter has recorded 

 some experiments to prove that the white excrescence is a hydrate and 

 not solid carbon disulphide. Prof. F. P. Venable, of the University of 

 Xorth Carolina, has studied anew this body and obtained evidence 

 that the amount of moisture in the air has a decided effect upon the 

 ease and rapidity of its production. Uo fixed law, however, could be 

 deduced. The following experiment is conclusive and confirms Bailors 

 results : An open-necked bell-jar, ground, greased, and tightly fitting 

 to a ground-glass plate was provided with a large rubber stopper 

 pieiced with two holes. Through one of these openings a calcium 

 chloride tube 250 mm. long was inserted, and through the othera glass 

 tube with a glass rod working tightly in it and rendered air tight by 

 rubber tubing. Inside the bell jar was placed a watch glass contain- 

 ing purified carbon disulphide supported above a vessel of fresh con- 

 centrated sulphuric acid. A small strip of previously dried filter paper 

 was attached to the end of the glass rod within the bell-jar, and when 

 this was lowered it dipped into the volatile liquid; the liquid rose rap- 

 idly in the pores of the paper, but even after some miDutes no sign of 

 a solid incrustation was visible. When, however, the sulphuric acid 

 was replaced by water the solid began to form immediately after the 

 lowering of the paper. By drawing air through the jar until it was 

 filled with aqueous vapor the solid hydrate suddenly and completely 

 melted away. Daring the evaporation of the carbon disulphide in an 





