January 20 1898] 



NATURE 



2^5 



The electrolytic extraction of metals from their ores is now 

 employed on a large scale, in the casq of gold, where it can be 

 profitably applied to the treatment of tailings and waste sludges ; 

 of zinc, especially by the recent Hoepfner method of working 

 from the chloride ; of aluminium, and of sodium. Aluminium 

 made its first appearance as a commercial product at the Paris 

 Exhibition of 1855. Its price at the time was not far off that of 

 silver. The cost is now equivalent to that of copper, whilst the 

 production has mounted to 2000 tons per annum, and is rapidly 

 increasing. I'rof. Richards, well known as the author of the 

 most complete treatise on aluminium, predicts that it is bound 

 to rank next to iron in its production and usefulness to man- 

 kind. The principal methods of extraction at the present time 

 are Hall's process, consisting of an electrolytic bath of pot- 

 assium fluoride, in which alumina produced from bauxite 

 IS continuously dissolved ; and Heroult's process, in which the 

 solvent consists of cryolite, the double fluoride of aluminium 

 and sodium. 



The manufacture of alkali has already undergone many 

 changes the past twenty-five years, one of which is the super- 

 session of the Le Blanc process by the ammonia-soda process of 

 Hemming and Solvay. The electrolytic 

 treatment of brine for the production of 

 soda and chlorine now threatens to 

 displace all the older chemical processes, 

 especially since the introduction of the 

 successful rocking apparatus of Castner 

 and Kellner, in which an end-to-end 

 flow of mercury through three compart- 

 ments prevents the mixing of the elec- 

 trolyte, and effects the separation of the 

 sodium and chlorine. A similar industry 

 is the manufacture of chlorate of potash 

 by electrolysis, in a tank divided by a 

 porous partition, with very thin iridio- 

 platinum anodes and iron kathodes. 

 The electrolyte is usually a solution of 

 chloride of potassium maintained at a 

 temperature of 45° to 50° C. The action 

 of this cell results in the formation at 

 the anode of hypochlorite, which is 

 immediately decomposed, with the for- 

 mation of chloride and chlorate of 

 potassium. In Switzerland and in 

 Sweden this process is worked with 

 great commercial success by the aid of 

 power derived from water. 



Amongst the class of electro-chemical 

 processes depending on dissociation and 

 combination at extremely high temper- 

 atures, Mr. Swan referred to the 

 manufacture of phosphorus and of 

 carborundum in the Acheson furnace. 

 To the same category belongs the pro- 

 duction of calcium carbide and a 

 number of analogous products obtained 

 by Moissan. Calcium carbide, for the 

 production of acetylene gas, is now 

 being manufactured at the rate of 20,000 

 tons per annum. 



The production of ozone, with its 

 secondary derivatives, vanillin and 



heliotropine, is dependent on another variety of electrical 

 action, in which intermittent or alternating currents of high 

 tension are employed. By the Andreoli and other practical 

 processes, ozone is now being commercially produced and 

 applied to numerous industries, such as the oxidation of oils, 

 the seasoning of linoleum, and the pnrification of brewers' 

 casks. 



Such are a few of the principal uses to which Volta's dis- 

 covery of the galvanic current is being applied. It remains to 

 be seen how far the electrolytic and other electrical processes 

 will supplant the older chemical processes as time goes on. We 

 are probably at present only on the edge of the field that remains 

 to be explored. Mr. Swan's advice to the numerous young 

 electricians who are setting out in life, is that some of them 

 should turn their eyes towards the rich possibilities that await 

 them in this direction. We often hear that the profession of 

 electrical engineering is already crowded. Here at least is a 

 world that still remains to be conquered. 



T//E BRIGHTOA MUNICIPAL SCHOOL OF 

 SCIENCE AND TECHNOLOGY. 



T^IIE accompanying illustration shows the external features 

 of the new School of Science and Technology opened at 

 Brighton by the Duchess of Fife a few days ago. The 

 building was designed by Mr. F. J. C. May, the Borough 

 Engineer and Surveyor. 



On the ground floor is a large vestibule with mosaic 

 flooring, from which a wide marble staircase leads to the top of 

 the building. A second staircase gives access to the three floors. 

 On each of the floors there is a corridor extending from the 

 front to the back of the building, for a depth of 162 feet, and 

 from these corridors the workshops, class-rooms, lecture 

 theatres, and laboratories open out on each side, with a master's 

 private room for each department. In the basement are situated 

 the boilers and engines for the electric lighting of the building, 

 and for the supply of hot water and steam for the laboratories ; 

 here also is a smithy with forges, electrical workshop, carpenter- 

 ing, plumbing, and brickwork and masonry shops, and a dynamo 

 room. 



On the ground floor leading from the vestibule are rooms 

 for the Principal, Secretary, Committee, and office ; on either 

 side of the corridor are an engineering drawing hall, an engineer- 

 ing workshop, engineering laboratory, metallurgical furnace 

 room, typography shop, and various class-rooms. The workshop- 

 is fitted with a Tangye's gas engine, lathes, planing, slotting and 

 drilling machines, &c. 



The first floor is devoted mainly to chemistry and physics. 

 The lecture theatres in both departments are fine halls, capable 

 of seating 220 and 120 respectively. The chemical laboratory is 

 fitted for forty-eight students working at one time, and is fully 

 equipped. Besides class and preparation rooms for each de- 

 partment, the accommodation on this floor comprises, among 

 others, rooms for photometry, and advanced physics, chemical 

 research room, balance room, and photographic dark room. 

 The second floor contains a lecture theatre and laboratory for 

 the natural sciences, and lecture and class rooms for dressmaking 

 and cookery. 



NO i473> VOL. 57] 



