TEANSACTIONS OF SECTION A. 513 



which are perliaps not altogether to be regretted the experiment was only par- 

 tially successful. In the meantime the work of Section A became heavier and 

 heavier, and as it seemed necessary to find some way of relieving its meetino-s it 

 was decided to hand over to the already established sub-section of Astron'omy 

 other subjects, such as meteorology, terrestrial magnetism, seismology, and, in 

 fact, anything that the majority of physicists are only too glad to ignore. 



When the Council of the British Association asked me to act fTs President of 

 such an enlarged sub-section I was very doubtful whether I ought to accept the 

 honour. In the first place, I felt incompetent, owing to my almost complete i"-nor- 

 ance of most branches of astronomy, and in the second place I do not approve of 

 the formation of sub-sections dealing with important branches of physics. If 

 I eventually consented, it was partly because I lacked the strength of mind to refuse 

 an honour of this kind, but partly because I was glad to have an opportunity of 

 raising the whole question of the organisation of our meetings. The ground for 

 such a discussion has, however, to a great extent disappeared, because"when the 

 Organising Committee of Section A met in the spring there appeared amongst those 

 present a sudden revival of interest in the subjects assigned to the sub-section, and 

 it was decided that the main section should not meet at all to-day, so as to allow 

 all members to help us in our discussions. The parent Section has, therefore 

 voluntarily submitted itself to absorption by its neglected offspring, which nov? 

 has to show that cosmical physics obey the laws of terrestrial phvslcs, and that 

 good absorbers are also good radiators. 



_ Gratifying as this reunion must be to us, it fails to realise one of the original 

 objects for which we have been called into existence, because instead of lighte'uincr 

 your work it has added to it by imposing upon you the burden of having^to listen 

 to a second Presidential Address. I will try to make this additional burden as 

 light as possible by concentrating my general remarks into a few sentences, and 

 then introducing the business of the Section by means of a contribution to its 

 scientific work, which I otherwise would have made in the ordinary course of the 

 meeting. 



To make pur meetings as fruitful as possible, we would make the fullest use of 

 the opportunities afforded us of personal contact and interchano-e of ideas. This 

 is not accomplished by dividing into separate camps as soon as we have come 

 together, but rather by finding some common ground for our debates. We should 

 not try to minister to the separate needs of the specialist in electricity, or in meteo- 

 rology, or in astronomy, but should impress upon each of these specialists that 

 he must bring before us the results of his investigations in so far as they bear 

 on the more general questions in which we all are, or ought to be interested. If 

 it is necessary to lighten the work of the Section this should be done by excludino- 

 all papers which are of interest only to specialists, or by establishing sub-section^s 

 for such papers. Let us divide— if divide we must— according to the character of 

 the^ contribution, rather than according to the subject it happens to deal with. The 

 difficult and, perhaps, unpopular censorship which such a course would involve 

 would probably be temporary only, as the character of the papers which are de- 

 sired for the main Section would soon become known, and the Increased attraction 

 and usefulness of our discussions would, I am convinced, in a few years compen- 

 sate for the initial trouble. AVe all require, occasionally, to be reminded that the 

 detail work which is necessary, and on which most of us are engaged, is only of 

 importance or interest if it helps us forward towards the solution of the great 

 problems of nature. 



Addressing myself more particularly to astronomers, I should like to say that 

 we shall always welcome them as members of Section A, and that the benefit we 

 shall derive from their contributions will be great in proportion as they consider 

 themselves to be citizens of the general empire of that Section, rather than inhabi- 

 tants of an independently governed state. 



There is a minor reform, or perhaps I ought to call it a protest, against one 

 of the traditions of the Association which I feel called upon to urge on you. Discus- 

 sion is our principal aim, and we are always trying to find suitable subjects for dis- 

 cussion ; yet wc are prevented by rule or custom from discussing the Presidential 



1902. 



