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with those of light and heat ; light and heat were ripples, 
the Hertzian waves billows in the aether. The long Hertzian 
waves, sometimes 1,000 feet in length, could be created by 
the rapid vibrations of electric charges of ordinary magnitude. 
What was more natural, therefore, than to suppose that 
light-waves, themselves electric waves so much more minute 
and delicate, were produced by the vibration of the very 
minute electric charges or “ electrons ” of which it was now 
supposed all matter was constituted ? This view had been 
confirmed by one of the most remarkable experiments of 
modern science — an experiment in which it was shown that 
a beam of light had actually been magnetised. 
Light-waves formed only a small percentage of the waves 
emitted by illumination produced artificially. Using ordinary 
incandescent lamps, one horse power would produce illumina- 
tion equal to that of 250 candies, whereas if the same power 
were utilized in producing only luminous rays without also 
producing useless heat, they could create an illumination 
equal to that of 5,000 candles. This increase in efficiency 
of our sources of artificial illumination was only likely to be 
brought about when the process of heating a solid substance 
to produce light was abandoned, and some other means of 
setting the “ electrons ” in vibration adopted. The glow 
worm and the firefly possessed this art, the whole of their 
radiation being useful light, and none of it useless heat. 
Mr. Birtwistle then went on to review the great progress 
made during the past ten years in the domain of electrical 
science, and what it had revealed as to the significance of the 
“ electron ” and its sources. The marvellous experiments 
of Professor J. J. Thomson, in which he succeeded in measuring 
the speed and mass of flying electrons in an X-ray tube, were 
reviewed ; it was shown that the origin of the X-rays them- 
selves was the sudden stoppage of the electrons on striking 
the tube, and that they differed from light in being a rapid 
succession of separate aether disturbances rather than a steady 
stream of waves. The sun’s corona and the Aurora Borealis 
were explained as due to the projection of electrons from the 
sun into the rarified atmosphere of the sun and earth res- 
pectively, in the latter case the electrons being guided into 
the Polar regions by the earth's magnetic force, and there 
producing the glow of the Aurora. It was then pointed out 
that the whirl of the electrons within the atom must cause 
it to lose its internal energy and in the end lead to its dis- 
integration, and thus to the transition of one kind of matter 
into another. In the past few years this had been discovered 
— it was the phenomenon of radio-activity. 
