THE BRITISH ASSOCIATION MEETING ,

• 1923.*

To the scientific layman, and particularly since the War, the annual event of the British Association Meetings has attained a considerable status, for even the greatest pedant among the scientists who preside or take part in the meetings never fails to present the more exciting aspects and potentiali- ties of his subject in relatively simple language, in order that the public may be inspired to support the cause of research.

For the last two or three years, physics has been in the public eye, to a greater extent than the other branches of science, partly on account of the excitement aroused four years ago, by the experimental verification of Einstein's theories of relativity ; and partly by the laboratory work which has resulted in a more intimate knowledge of the ultimate structure of matter. Admittedly, Sir Ernest Ruther- ford is the contemporary master-physicist in this special department of research. Therefore, an additional thrill attended this year's meeting inasmuch as he presided and, in the presidential address, dealt at length with his latest researches into the electrical structure of matter. The last Liverpool meeting of the Association took place in the year 1896, and the President took that year as the starting point

• The Advancement of Science, 1923. London : John Murray. [69. net.] for an outline of the work that had been done, and the results that had been achieved since the electrical nature of matter was suspected. In 1897, the closed door- of the atom was thrown open to reveal the electron, and, thereafter, the study of radio-activity revolutionized the whole conception of the atom and of the forces which bind it together. " The radio- active elements provide us for the first time with a glimpse into nature's laboratory, and allow us to watch and study, but not control the changes that have their origin in the heart of radio-active atoms." The atomic explosions in which consist the spontaneous transformation of atoms of radio- active matter accompanied by the emission of the character- istic a, p or y rays, " involve energies which are gigantic compared with those involved in any ordinary physical and chemical process."

But as regards the possibilities for the ultimate intensifica- tion and control of those energies—the dream of all Utopia- builders—Sir Ernest was extremely discouraging. Indeed he disclosed, for the first time, the fact that of late there has been a change of point of view on this subject, and that now it is no longer certain that all atoms alike contain the hidden stores of energy with which the millennium is to be attained.

It is now suggested instead that the radio-active elements in which, without any doubt, these energies arc to be found, represent the sole survivals of types of elements that were common in the long-ago ages of the earth's formation. And, owing to their slow rate of transformation, it is possible to regard these atoms of uranium and thorium, which have survived, as not having completed the cycle of change through which all ordinary atoms have long since passed and as being still in that " excited " state, where the units of the nucleus are not yet arranged in final equilibrium, and where there is still a surplus of energy that can be released in radiation.

Thus it would appear that a store of energy, awaiting release in order either to assist or to destroy mankind, is not a property of all atoms, but only of those radio-active atoms which have not yet achieved ultimate equilibrium.

The President covered so much ground that it would merely be bewildering to attempt to follow him in so short a space. The methods of fixing the mass of a single atom, the difficulties and triumphs of the quantum theory led him finally to the question of the detailed structure of the atom, and from the comparatively simple problems concerning the outer atom to the mystery of the nucleus, so far very little elucidated. Apparently we may rest, quite justifiably, in the thought that the atoms of matter are built up of the electron and the proton or hydrogen nucleus. With these two electrical units analysis must be content for the moment, there being always the reservation that further inquiry may some day wove these units to be complex and divisible into yet other layers of fundamental entities. It is one of the joys of scientific inquiry that, as a rule, the solution of any problem is attended by a number of fresh problems arising on the new horizon. The President of the section of mathematics and physics discoursed at length, and rather technically, on the recent investigations of the origin of spectra and the applica- tion of the quantum theory ; and in the general discussion Sir Oliver Lodge, with his usual vigorous partisanship on behalf of the aether, propounded some interesting hypotheses of a speculative nature as to the genesis of matter by rotations in this otherwise stationary nether.

A somewhat speculative atmosphere seems to have pervaded the whole meeting, for, even in the chemistry section, Pro- fessor Donnan, discoursing on the " physical chemistry of interfaces" (or, the " philosophy of edges and surfaces," as it might be called), was led into pronouncing the rather sig- nificant conclusion that " It is probable that along and across 'living surfaces' there is a continual flux of activity. Does the very existence of these surfaces depend on some special form of activity ? . . . There is encouragement if we may assume that the physico-chemical manifestations of life are functions of .the same powers and potentialities of electrons, atoms, . . . etc., that we find, in what we call inanimate environments. Life would then be simply a new functional relationship of very old parameters. . .

In the physiological section, Profess^: Nato discussed the still debatable question the co-operation in animals and plants and betw:en animals and plants which is known

as symbiosis in contradistinction to parasitism. 'Whether this desirable principle has evolutionary status is not yet decided.

The very vital question of birth-control was approached in the section of economics, both in Sir William Beveridge's most interesting address, and afterwards in the general discussion in which Dr. Marie Stopes took an active part. Sir William, in a general survey of European conditions, and of the problem of unemployment in this country, con- cluded that unemployment wt 13 no proof of over-population ; and he opposed Mr. Keynes' theory that even before the War Europe was threatened by the instability of an excessive population dependent on a complicated and artificial organiza- tion. He deprecated the practice of birth-control as a solution of present-day evils.

Although Dr. Stopes opposed him in her defence of constructive birth-control, by quoting the annual sum spent in this country on the maintenance of the unemployable, she did not bring up the question of the sterilisation of the unfit, which in our opinion is of the first importance and which cannot involve the same waste of time in controversy as that of birth-control.

Egypt and the education of the people are two of the remaining subjects which we have no space to discuss.

In fact, the whole meeting was stimulating from beginning to end, and to the full realized its purpose—that of the detaile4 survey of this great period in the advancement of science.

AMETIIE MCEWEN.