

SIR WILLIAM SIEMENS, F.R S. 367 



In glancing back upon its history during the 128 years of its 

 i-xistriiiv, \\v discover that the Society of Arts was the first 

 institution to introduce science into the industrial arts ; it was 

 Hirou-li die Society of Arts and its illustrious Past President, the 

 late Prince Consort, that the first Universal Exhibition was pro- 

 pusi-d, mid brought to a successful issue in 1851 ; and it is due to 

 the same society, supported on all important occasions by its 

 present President, the Prince of Wales, that so many important 

 changes in our educational and industrial institutions have been 

 inaugurated, too numerous to be referred to specifically on the 

 present occasion. 



Amongst the practical questions that now chiefly occupy public 

 attention are those of Electric Lighting, and of the transmission 

 of force by electricity. These together form a subject which has 

 occupied my attention and that of my brothers for a great number 

 of years, and upon which I may consequently be expected to 

 dwell on the present occasion, considering that at Southampton I 

 could deal only with some purely scientific considerations involved 

 in this important subject. 



I need hardly remind you that electric lighting, viewed as a 

 physical experiment, has been known to us since the early part of 

 the present century, and that many attempts have, from time to 

 time, been made to promote its application. Two principal diffi- 

 culties have stood in the way of its practical introduction, viz., the 

 great cost of producing an electric current so long as chemical 

 means had to be resorted to, and the mechanical difficulty of con- 

 structing electric lamps capable of sustaining, with steadiness, 

 prolonged effects. 



The dynamo-machine, which enables us to convert mechanical 

 into electrical force, purely and simply, has very effectually disposed 

 of the former difficulty, inasmuch as a properly conceived and well 

 constructed machine of this character converts more than ninety 

 per cent, of the mechanical force imparted to it into electricity, 

 ninety per cent, again of which may be re-converted into 

 mechanical force at a moderate distance. The margin of loss 

 therefore, does not exceed twenty per cent., excluding purely 

 mechanical losses, and this is quite capable of being further 

 reduced to some extent by improved modes of construction ; but 

 it results from these figures that no great step in advance can be 



