August 26, 1920] 



NATURE 



825 



supplying to the water the oxygen necessary for the 

 respiration of living protoplasm. Our object must be 

 to estimate the rate of production and rate of destruc- 

 tion of all organic substances in the sea. 



To attain to an approximate census and valuation of 

 the sea — remote though it may seem — is a great aim, 

 but it is not sufficient. We want not only to observe 

 and to count natural objects, but also to under- 

 stand them. We require to know not merely what 

 an organism is — in the fullest detail of structure 

 and development and affinities — where it occurs 

 —again in full detail — and in what abundance in 

 different circumstances, but also how it lives and 

 what all its relations are to both its physical and its 

 biological environment, and that is where the physio- 

 logist, and especially the biochemist, can help us. 

 In the best interests of biological progress the day of 

 the naturalist who merely collects, the day of the 

 anatomist and histologist who merely describe, is 

 over, and the future is with the observer and the 

 experimenter animated by a divine curiosity to enter 

 into the life of the organism and understand how it 

 lives and moves and has its being. " Happy indeed 

 is he who has been able to discover the causes of 

 things." 



Cardiff is a seaport, and a great seaport, and the 

 Bristol Channel is a notable sea-fisheries centre of 

 growing importance. The explorers and merchant 

 venturers of the south-west of England are celebrated 

 in history. What are you doing now in Cardiff ta 

 advance our knowledge of the ocean ? You have here 

 an important university centre and a great modern 



national museum, and either or both of these homes 



of research might do well to establish an oceano 



graphical department, which would be an added glorj 



to your city and of practical utility to the country. 



This is the obvious centre in Wales for a sea-fisheries 



institute for both research and education. Many 



important local movements have arisen from British 



Association meetings, and if such a notable scientific 



I development were to result from the Cardiff meeting 



j of 1920, all who value the advance of knowledge and 



I the application of knowledge to industry would 



applaud your enlightened action. 



In a wider sense, it is not to the people of 

 Cardiff alone that I appeal, but to the whole popula- 

 tion of these islands, a maritime people who owe 

 everything to the sea. I urge them to become better 

 informed in regard to our national sea-fisheries and to 

 take a more enlightened interest in the basal principles 

 that underlie a rational regulation and exploitation 

 of these important • indiistries. National efficiency 

 depends to a very great extent upon the degree . in 

 which scientific results and methods are appreciated 

 by the people and scientific investigation is promoted 

 by the Government and other administrative authori- 

 ties. The principles and discoveries of science apply 

 to aquiculture no less than to agriculture. To in- 

 crease the harvest of the sea the fisheries must be 

 continuously investigated, and such cultivation as is 

 possible must be applied, and all this is clearly a 

 natural application of the biological and hydro- 

 graphical work now united under the science of 

 oceanography. 



Summaries of Addresses of Presidents of Sections of the British Association. 



Mathematical and Physical Science. < 



Prof. Eddington's presidential address to Section A I 

 deals with the investigation of the internal conditions | 

 of the stars. Most of the naked-eye stars have densi- i 

 ties so low that they may be treated as spheres of 

 perfect gas (giant stars). In familiar hot bodies the 

 energy existing in the aether (radiant heat) is ex- 

 tremely small compared with that associated with the 

 matter (molecular motions) ; conditions might exist in 

 which this disproportion was reversed; but the stars 

 are of just such a mass that the two kinds of energy 

 are roughly equal. It is thought that this balance 

 cannot be a coincidence, but determines why the 

 masses of the stars are always close to a particular 

 value. From astronomical data as to the masses and 

 radiation of the stars it is possible to determine the 

 opacity of stellar material to the radiation traversing 

 it. The opacity turns out to be very high and of the 

 same order of magnitude as that found for X-rays in 

 the laboratory. (At the high temperatures in the stars 

 the radiation consists mainly of soft X-rays.) A 

 rather surprising result is that the opacity varies very 

 little with the temperature of the star or wave-length 

 of the radiation. The discussion leads to many 

 astronomical results which appear to be generally con- 

 firmed by observation ; in particular, it fixes within | 

 fairly narrow limits the period of a mechanical pulsa- j 

 tion of any star, and this agrees in all known Cepheid 

 variables with the observed period of light-pulsation. 

 The question of the source of a star's heat is raised in 

 an acute form by these investigations. It apF>ears that 

 the energy of gravitational contraction is quite in- 

 adequate. The recent experimental results of Aston i 

 and Rutherford seem to throw some new light on the 

 often-discussed question whether sub-atomic energy 

 can be made available in the stars. The address con- 

 cludes with some observations on the legitimate place 

 of speculation in scientific research. 



NO. 2652, VOL. 105] 



Chemistry. 



Mr. C. T. Heycock deals in his presidential address 

 to Section B with the manner in which our present 

 rather detailed knowledge of metallic alloys has been 

 acquired, starting from the sparse information which 

 was available thirty or forty years ago, and sketches 

 briefly the present position of the subject. He 

 considers chiefly the non-ferrous alloys, not because 

 any essential difference in type exists between these 

 and ferrous alloys, but because the whole field pre- 

 sented by the chemistry of the metals and their alloys 

 is too vast to be covered in an address of reasonable 

 length. Though Reaumur in 1722 employed the micro- 

 scope to examine the fractured surfaces of white and 

 grey cast-iron and steel, and Widmanstatten in 1808 

 polished and etched sections from meteorites, the 

 founder of modern metallographv is undoubtedly 

 H. C. Sorby, whose methods of polishing and etching 

 alloys and of vertical illumination are used to-day by 

 all who work at this subject. The first important clue 

 to what occurs on cooling a fused mixture of metals 

 was given by Guthrie's experiments on cryohvdrates, 

 and these researches, with those of Sorby, undertaken 

 as they were for the sake of investigating natural 

 phenomena, are remarkable examples of how purely 

 scientific experiment can lead to most important prac- 

 tical results. Raoult's work on the depression of the 

 freezing point of solvents due to the addition of dis- 

 solved substances led to the establishment bv van't 

 Hoff of a general theory applicable to all solutions. 

 Later experiments established the similarity between 

 the behaviour of metallic solutions or alloys and that 

 of aqueous and other solutions of organic' compounds 

 in organic solvents; and in 1807 Neville and Hevcock 

 determined the complete freezing-point curve of the 

 copper-tin alloys, confirming and extending the work 

 of Roberts-Austen, Stansifield, and Le" Chatelier. 

 These were probably the first of the binary alloys on 



