CHEMISTRY. 403 



or Grove cells a considerable volume of nftrogeu and hydrogen is lib- 

 erated in the separate tubes in a few minutes. The re-action may be 

 thus represented : 



— Pole 6NaCl + Pole 



The HCl is of course fixed by the free ammonia. The experiment is 

 suitable for the lecture table. (Chem. News, liv, 16.) 



Electrolytic Aluminium. — L. Senet has devised a new i)rocess for ob- 

 taining aluminium, as well as copper, silver, etc., by electrolysis. He 

 exposes a saturated solution of sulphate of alumina, separated from a 

 solution of chloride of sodium by a porous vessel, to a current of 6 or 

 7 volts and 4 amperes. The double chloride of aluminium and sodium 

 is decomposed, and the aluminium is deposited upon the negative elec- 

 trode. (Cosmos, August 10, 1885.) 



Researches on. Titanium and its Compounds, by Otto Freiherr von der 

 Pfordten — First Part. — The results of this lengthy investigation are 

 thus summarized by the author : • 



(1) Pure sulphuretted hydrogen can be prepared by drying the gas 

 over phosphorus pentoxide and passing it through chromous chloride, 

 which removes the oxygen. 



(2) The hydrogen evolved in the usual way by zinc and acid contains 

 no oxygen. 



(3) With titanium and some other elements having a great affinity 

 for oxygen the sulphides can best be obtained by the action of sul- 

 phuretted hydrogen on the chloride. The action of sulphuretted hy- 

 drogen on the oxide does not give pure products. 



(1) At a low temperature sulphuretted hydrogen reduces tetrachlo. 

 ride of titanium to the dichloride, and at a higher temperature another 

 compound forms, probably a sulpho-chloride. 



(5) On the other hand, at a red heat, a pure crystalline disulphide is 

 obtained, derived from the product first formed. 



(6) Disulphide of titanium is oxidized by carbonic acid gas free from 

 oxygen. (The only known case of a metallic sulphide decomposing 

 carbon dioxide.) 



(7) Disulphide of titanium in nitrogen is changed to sesquisulphide. 

 Hydrogen effects the same at a high heat in glass. 



(8) The same is reduced by hydrogen in a highly-heated platinum 

 tube to monosulphide. 



