281 



i)iscovi:hy 



Fig. .'.—Tin; POWER ST.\TION AT VER.MORK, SWEDEN. 

 (iS.v kinil permission ol Meisrs. Utigmans, Green & Co.) 



of these power-developments is illustrated in Fig. 2. 

 The supply of water is there derived from Lake Mos- 

 vand, 3,000 feet above sea-level. From there the 

 water is led for about three miles through a tunnel in 

 the rock, to a distributing basin or reserv-oir excavated 

 from the rock, and thence, as illustrated in Fig. 2, 

 down ten steel pipes 4 to 7 feet wide through a fall in 

 level of 940 feet, to the turbines at the base. Each 

 turbine generates 14,500 horse-power, so that altogether 

 145,000 horse-power is generated. After issuing from 

 this power station, the water is again utilised through 

 being led, in a similar manner, to a second station 

 about 1,000 feet lower down, where a further 162,000 

 horse-power is developed. Still further possibilities in 

 power generation at the first site are revealed in the 

 surplus water seen in the photograph, which at present 

 serves only for display. 



It is of interest to note that in the development of 

 these factories in Norway, the co-operation of Germany 

 was extended to the Norwegian Company, through the 

 agency of the Badischc Anilin und Soda Fabrik ' and 

 other allied organisations. Before the war, however, 

 the German interest was withdrawn and, with some 

 foresight, the process was installed in Germany. 

 However, the output of the Norwegian factories, which, 

 after 1916, exceeded 50,000 tons of ammonium 



' Where the big explosion on the Rhine recently took place. 



nitrate annually, formed a material contribution to 

 this countrj-'s supplies of explosives. 



II 

 The experimental manufacture of steel in an 

 electric furnace falls to the credit of this country 

 through the work of William von Siemens, in 1878, 

 and Ferranti, who developed the first type of induction 

 furnace in 1887. Electric furnaces, which are now 

 widely used for the production of steel of all classes, 

 and which have already largely supplanted the 

 " crucible " process, are generally operated by the 

 principle of the low-tension arc. An example of this 

 form of arc is seen in everyday life in the flashes- 

 which appear from the trolley poles of cars, and from 

 the rails at places where the surface is uneven or coated 

 with foreign insulating matter. An electric discharge 

 is thus produced which, tlirough its excessive tempera- 

 ture, leads to a volatihsation of some of the metal, 

 thus giving the appearance of a luminous flame. The 

 principle generally applied in electric furnace opera- 

 tion is that of causing an arc to play between a large 

 block or electrode of carbon (or a scries of such. 

 electrodes) and the surface of metal or material in the 

 crucible to be treated. In this way, temperatures can 

 be reached which are well beyond the zone of those 

 given by any form of fuel-heating. The temperature 



