282 



DISCOVi:UY 



is not less fundamental in importance — the appli- 

 cation of electricity to the crucible of the chemist. 

 By^this alliance with chemistrj' Galvani, Volta, and 

 others first achieved systematically the production of 

 electricity, and Davy, in breaking up chemical com- 

 pounds into their constituent elements by means of 

 an electric current, demonstrated the molecular 

 structure of matter. From this early time in the 

 nineteenth century onwards, as improved methods of 

 producing an electric current in increasing magnitudes 

 were discovered, one of the first experiments to be 

 tried with the new power weis its effect on chemical 

 change. In all instances experiments were first done 

 in a laboratory, scientifically and on a small scale, but 

 the industrial application of electricity was always 

 kept in view, and the course of research was largely 

 guided by industrial needs. 



It is noteworthy that a very large share both of the 

 pioneering work in industrial electro-chemistry, and 

 of purely scientific discoveries which are the basis of 

 these processes, was done by workers of this country. 

 The lead, however, in the development of these 

 industries has, in nearly every instance, been left to 

 other countries, where large-scale industrial enter- 

 prises are not characterised by the same degree of 

 inertia as at home. Nevertheless, the development in 

 this country has been very rapid. As recently as 1887, 

 a noteworthy landmark was created in the construction, 

 for the electrical production of aluminium alloys in 

 Staffordshire, of an electric generator working the 

 then record production of 500 horse-power. To-day, 

 the installation of turbo-generators of 50,000 horse- 

 power passes without public notice, and it is hardly a 

 matter for comment that at least one electric supply 

 company in this country distributes coal-generated 

 power approaching in magnitude the total developed 

 capacity of the Niagara Falls. 



In one respect our country appears to be at an 

 obvious disadvantage, namely, in the scarcity of 

 waterfalls which can be harnessed for the production 

 of power. For this we have largely to use coal, and 

 as coal is dearer than water, the utilisation of large 

 water powers such as exist in Scandinavia and 

 America seems to offer a marked advantage economi- 

 cally over steam-power stations. But, fortunately 

 for this country, present-day tendencies have already 

 reversed this position. For the most favourable 

 water-powers in accessible parts of the world have 

 already been harnessed, and further developments can 

 only be made at greater cost and in places farther afield, 

 while, in the case of steam power, continual progress 

 in power-development is being made, with a consequent 

 increase in economy. The operation of this factor is, 

 indeed, now leading to a redistribution of electro- 

 chemical industries from large water-power centres 



like Norway and Niagara, to districts near the coal- 

 fields where, incidentally, there are available also the 

 very large supplies of water needed for cooling modern 

 condensers. 



Apart from the commercial bearing of this subject, 

 there are several directions in which electro-chemistry 

 is of vital and national interest. The present dis- 

 cussion of this subject \vill be limited to two of the 

 more outstanding of these developments ; 



(i) The manufacture from the atmosphere of 

 nitrogen compounds wliich form the basis of fertilisers 

 and explosives. In this electrical synthesis, the 

 starting-point or raw materials used consist solely of 

 the ecu-th's atmosphere and water, together, in some 

 cases, with lime. 



(2) The preparation of alloy-steels of extreme hard- 

 ness and tensile properties. These products are utilised 

 in the manufacture of high-speed cutting steels, and 

 for the construction of the armour plate of battleships. 

 It is largely to the special properties of this metal that 

 we owe our margin of superiority in naval armaments. 



I 



The li.xation of atmospheric nitrogen is based on the 

 scientific discovery of Cavendish, as early as 1784, 

 that nitrogen can be made to combine with oxygen, 

 by exposing both gases to an electric discharge. This 

 reaction was investigated later more completely by 

 Lord Rayleigh in 1897, and the industrial manufacture 

 of nitric acid by this means was first undertaken by 

 McDougal and Howies at Manchester in 1900. 



The stimulus which has, in recent years, been given 

 to this enterprise was created by the realisation that 

 the world's supphes of nitrates, which have resided 

 hitherto mainly in the saltpetre beds of Chile, are 

 within a measurable distance of exhaustion. More- 

 over, the experience of the recent war has emphasised 

 the disadvantages of fetching from so great a 

 distance the material which forms the primary 

 requirement of agriculture and of all explosives. 

 There is, however, a source nearer home. The air 

 over a single square mile of the earth's surface is 

 estimated to contain about 20,000,000 tons of nitrogen, 

 which is approximately equivalent to thirty times the 

 quantity of combined nitrogen contained in the world's 

 production for the year 1913 of Chile nitrate and 

 ammonium sulphate, an alternative source. The 

 conversion of this into the nitrogen compounds so 

 sorely needed in the arts of peace is therefore a most 

 important chemical and engineering problem. 



One of the main processes for accomplishing the 

 artificial production of nitrates consists in subjecting 

 air to an electrical discharge or so-called high-tension 

 arc. By this means, the nitrogen and oxygen are 



