1 98 THE ADDRESSES, LECTURES, ETC., OF 



which amount is equivalent to the total coal consumption of the 

 world. 



In stating these facts in my inaugural address on assuming the 

 presidency of the Iron and Steel Institute, I ventured to express 

 the opinion that in order to utilise natural forces of this descrip- 

 tion at distant towns and centres of industry the electric con- 

 ductor might be resorted to. This view was at that time 

 unsupported by experimental data such as I have been able since 

 then to collect, and before concluding this lecture I propose to 

 bring some of the results of these further inquiries before your 

 notice. 



Our knowledge of electric force is, as you are aware, of very recent 

 origin. The frictional electrical machine and the galvanic battery 

 have been utilised for producing slight effects at great distances, 

 thus giving rise to one of the great institutions of the present age, 

 the Electric Telegraph. We have hitherto failed, however, to 

 produce by means of electricity, effects in any way commensurate 

 with those produced through the combustion and distillation of 

 coal, which provide us with the means of driving our factories 

 and lighting our towns with gas. It can be demonstrated, indeed, 

 that the galvanic battery, which is dependent for its development 

 of energy on the combustion of zinc, could never rival the effects 

 due to the combustion of coal economically, for the simple reason 

 that it takes 12 pounds of coal to separate a pound of zinc from 

 its ores, while the amount of energy liberated in the combustion or 

 oxidation of a pound of zinc is represented by 1400 heat units, 

 whereas that by the combustion of a pound of ordinary coal is 

 represented by 12,000 similar units. 



The great discovery by Faraday of the induced current has 

 enabled us, however, to produce electricity by the expenditure of 

 force, and by a particular arrangement of a rotative armature and 

 electro-magnets (which is chiefly due to my brother, Dr. "Werner 

 Siemens), the current so produced may be accumulated and 

 directed in such a manner as to produce continuous currents, more 

 powerful in their quantitative effects than could be accomplished 

 by batteries or any other means. 



Very powerful currents indeed are produced by means of these 

 machines, Plate 4, properly called Dynamo-Electric, by the expen- 

 diture of mechanical force only, in imparting rotative motion to an 



