2 THE PRESIDENTIAL ADDRESS. 
by Becquerel was announced early in 1896. Even the most imagina- 
tive of our scientific men could never have dreamed at that time of 
the extension of our knowledge of the structure of matter that was to 
develop from these two fundamental discoveries, but in the records of 
the Liverpool Meeting we see the dawning recognition of the possible 
consequences of the discovery of X-rays, not only in their application 
to medicine and surgery, but as a new and powerful agent for attacking 
some of the fundamental problems of physics. The address of Pro- 
fessor J. J. Thomson, President of Section A, was devoted mainly to 
a discussion of the nature of the X-rays and the remarkable properties 
induced in gases by the passage of X-rays through them—the beginning 
of a new and fruitful branch of study. 
In applied physics, too, this year marked the beginning of another 
advance. In the discussion of a paper which I had the honour to 
read, on a new magnetic detector of electrical waves, the late Sir 
William Preece told the meeting of the successful transmission of 
signals for a few hundred yards by electric waves which had been made 
in England by a young Italian, G. Marconi. The first public demonstra- 
tion of signalling for short distances by electric waves had been given 
by Sir Oliver Lodge at the Oxford Meeting of this Association in 1894. 
It is startling to recall the rapidity of the development from such small 
beginnings of the new method of wireless intercommunication over the 
greatest terrestrial distances. In the last few years this has been followed 
by the even more rapid growth of the allied subject of radiotelephony as 
a practical means of broadcasting speech and music to distances only 
limited by the power of the transmitting station. The rapidity of these 
technical advances is an illustration of the close interconnection that 
must exist between pure and applied science if rapid and sure progress is 
to be made. The electrical engineer has been able to base his technical 
developments on’ the solid foundation of Maxwell’s electromagnetic 
theory and its complete verification by the researches of Hertz, and also 
by the experiments of Sir Oliver Lodge in this University—a verifica- 
tion which was completed long before the practical possibilities of this 
new method of signalling had been generally recognised. The later 
advances in radiotelegraphy and radiotelephony have largely depended 
on the application of the results of fundamental researches on the 
properties of electrons, as illustrated in the use of the thermionic valve 
or electron tube which has proved such an invaluable agent both for 
the transmission and reception of electric waves. 
It is of great interest to note that the benefits of this union of pure 
and applied research have not been one-sided. If the fundamental 
researches of the workers in pure science supply the foundations on 
which the applications are surely built, the successful practical applica- 
tion in turn quickens and extends the interest of the investigator in 
