EVENING DISCOURSES. 



FIRST EVENING DISCOURSE 

 Friday, September ii, 1936. 



SCIENCE AND ELECTRIC LIGHTING* 



BY 



CLIFFORD C. PATERSON, O.B.E. 



There are here two lamps. A casual glance does not indicate any great 

 difference between them. That is because one of them is one of the very 

 latest products of the research laboratories of the industry of modern lamp 

 manufacture. It is the latest born of a family of which the brothers and 

 sisters are very different from this, for they have the most varied colours 

 and shapes. We see some of them high up on buildings — long stems of 

 different coloured light ; others as brilliant sources lighting our streets 

 with yellow or with greenish light ; others in large reflectors floodlighting 

 buildings with colours. The experience gained with all these other 

 members of the family has in effect led research men to this latest simple 

 and ordinary looking lamp. They are modern — these lamps — the new 

 generation of the lighting world. 



This other lamp is the youngest descendant of an ancient and illustrious 

 line, an entirely different family, which started nearly sixty years ago at 

 Newcastle, when Joseph Swan first showed how a fine rtem of carbon could 

 be made to glow in a vacuum when electricity was passed through it. His 

 was one of the very earliest electric lamps. Since that day few industrial 

 products have had lavished upon them a greater measure of scientific 

 thought and research. This research has had for its object to obtain as 

 much light as possible out of a current carrying filament, with as small an 

 expenditure of electricity as possible. The result of all the effort has been 

 to yield an improvement, of about ten times, of the modern filament lamp 

 over Swan's lamp of sixty years ago. 



Scientific research on the newer and more varied family of lamps is 

 naturally being carried on with the greatest intensity. 



I want first to use these two lamps to illustrate the two fundamentally 

 different methods for producing electric light. In the one we obtain light 

 from solids, in the other from vapours or gases. In the newer kind of 

 lamps the light comes from vapour which becomes brilliantly luminous 

 when electricity is made to pass through it. The inner part of the lamp 

 is only a container for a very small volume of vapour contained in a space 

 about 1 in. long and J in. diameter. A current has to be made to pass 

 along this little enclosure. The secret of success has lain, of course, in 

 learning how to do this with the materials which nature and man's art 

 can put at our disposal. But we need not concern ourselves at the moment 

 with how it is done. 



* Readers who wish to pursue this matter in greater detail are referred to the 

 Journal of the General Electric Co. Ltd., Wembley, Feb. (1937), i Q which the dis- 

 course is printed complete with illustrations, and from which reprints are available. 



