12 Professor T. E. Thorpe [Jan. 17, 



wire gauze, which, when the receptacle is in position, completely 

 surrounds the cathode. The positive electrode is connected with the 

 lid of the vessel, which is provided with openings for the escape of 

 the gases resulting from the electrolysis, and is suital)ly insulated. 



As the electrolysis proceeds the alkah metal, being much lighter 

 than the molten caustic, rises from the negative electrode and passes 

 into the receiver, the gases escaping around the edges of the cover. 

 The molten metal collects on the surface of the caustic, and is 

 removed by means of a large perforated spoon, the perforations 

 enabling the melted caustic to flow out, while the metal remains in 

 the spoon. As the several vessels are thus skimmed in succession the 

 fused sodium is collected into an iron vessel, whence it is poured into 

 moulds in which it congeals, forming blocks of the size and shape of 

 an ordinary building brick. These, after being trimmed to remove 

 adherent oxide, are immersed in paraffin oil, and are then packed 

 into large iron drums holding about 6 or 7 cwt., capable of being 

 closed air-tight, and protected in transit by an outer casing of wood. 



The due regulation of the volume and intensity of the current is 

 a matter of the greatest importance in order to obtain the most 

 economical yield of the metal. Xo very high temperature is needed ; 

 indeed, the temperature of the fused caustic soda should not be much 

 higher than that of its melting point. By suitably regulating the 

 current, the soda, in fact, may l)e maintained at the proper temperature 

 and in the proper degree of fluidity without extraneous heat. Fresh 

 melted caustic soda is added to the vessel from time to time to replace 

 the metal removed, and in this manner the process is made con- 

 tinuous. 



The Oastner process is now worked in England at Wallsend-on- 

 Tyne, and at Weston Point, in Cheshire ; at Rheinfelden, in 

 Germany ; at Clavaux, in France ; also in Switzerland, and at 

 Niagara, in America. The present yearly output amounts to about 

 5000 tons, but the plant already laid down is capable of producing at 

 least twice this quantity. 



The greater quantity of the sodium made in England is sent to 

 Glasgow, where it is converted into sodium cyanide by the Cassel 

 Cyanide Company for use in the extraction of gold. As gold is, I 

 suppose, generally considered the principal material factor in pro- 

 curing the comforts and conveniences of life, Davy's great discovery 

 may be thus said to have secured the primary object which the pro- 

 jectors of the Royal Institution had in view. Other important uses 

 of sodium are in the manufacture of peroxide for bleaching purposes, 

 of artificial indigo, and of a number of other synthetic dye stuffs and 

 of drugs like antipyrin. 



It need hardly be said that this extraordinary development of 

 the manufacture has not been without its influence on the price of 

 sodium. A quarter of a century ago it was a comparatively rare 

 metal, and a stick of it was regarded as a chemical curiosity, to be 



