THE,,PRESIDENTIAL..ADDRESS. 
| ae Ee CECTRICAL STRUCTURE 
OF MATTER. 
BY 
PROFESSOR SIR ERNEST RUTHERFORD, 
DSc. Orn. MPa... eo: 
PRESIDENT OF THE ASSOCIATION. 
_ Iv was in 1896 that this Association last met in Liverpool, under the 
_ presidency of the late Lord Lister, that great pioneer in antiseptic 
_ surgery, whose memory is held in affectionate remembrance by all 
nations. His address, which dealt mainly with the history of the 
application of antiseptic methods to surgery and its connection with 
the work of Pasteur, that prince of experimenters, whose birth has 
been so fittingly celebrated this year, gave us in a sense a completed 
page of brilliant scientific history. At the same time, in his opening 
remarks, Lister emphasised the importance of the discovery by Réntgen 
of a new type of radiation, the X-rays, which we now see marked the 
beginning of a new and fruitful era in another branch of science. 
‘The visit to your city in 1896 was for me a memorable occasion, 
for it was here that I first attended a meeting of this Association, and 
here that I read my first scientific paper. But of much more import- 
ance, it was here that I benefited by the opportunity, which these 
gatherings so amply afford, of meeting for the first time many of the 
distinguished scientific men of this country and the foreign representa- 
tives of science who were the guests of this city on that occasion. The 
year 1896 has always seemed to me a memorable one for other reasons, 
for on looking back with some sense of perspective we cannot fail to 
recognise that the last Liverpool Meeting marked the beginning of what 
has been aptly termed the heroic age of Physical Science. Never before 
in the history of physics has there been witnessed such a period of 
intense activity when discoveries of fundamental importance have 
followed one another with such bewildering rapidity. 
_ The discovery of X-rays by Réntgen had been published to the 
world in 1895, while the discovery of the radioactivity of uranium 
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