376 



NATURE 



[July io, 1919 



tion. On Monday last a kcture on Chemistry 

 in Reconstruction was gw^n bv Sir WiUiam 

 Tilden, and yesterday Prof. W. H. Bragg lec- 

 tured on Sound under Water and its Applications. 

 The following lectures will be delivered at 5.30 on 

 the dates named: — July 11, Coal Conservation, Prof. 

 H. E. Armstrong; July 14, Progress in Range-finders, 

 Prof, .\rchibald Barr;"july iS, Explosives, J. Young; 

 July 21, Progress in Aviation during the War Period, 

 L. Bairstow; July 23, How the Cotton Plant Feeds 

 as well as Clothes Is, S. E. de Segundo; July 25 

 (6 p.m.), \ Few Thoughts on the Development of 

 I.ondon, Raymond Unwin ; and July 28, Scientific 

 Lighting and Industrial Efficiency, L. Gaster. 



STRONG ELECrROLYlES AND 

 lONISATION. 



IT is well known that the behaviour of strong electro- 

 lytes is verv difficult to reconcile with the usually 

 accepted theory of ionisation, in that the change of 

 the degree of ionisation with the concentration is 

 completely at variance with the requirements of the 

 law of mass action. The abnormality of this very 

 important group of substances is discussed in a series 

 of papers by J. C. (ihosh (Journ. Chem. Soc., 1918, 

 vol. cxiii., pp. 44c), 627, 707, 790), who contends that 

 the fundamental idea underlying the Arrhenius theory 

 is not applicable to strong electrolytes. In place of this 

 theory the author puts forward the view that the strong 

 electrolytes are completely ionised, and that there is 

 no question of the existence of non-ionised molecules 

 in the usually accepted sense. The relations between 

 the ions are c-ontrolled by the electrical forces, the 

 magnitude of which corresponds with a certain 

 potential which is characteristic of a given solution 

 of an electrolyte. This potential affords a measure 

 of the work which is required to free the ions from 

 the influence of their mutual forces. Kinetic con- 

 siderations susrgest that the ions become " free " 

 when their velocitv exceeds a certain critical value, 

 the fraction of the ions in this condition at any 

 moment being shown by the ratio of the conductivity 

 of the electrolvte in the given solution to the con- 

 ductivity at infinite dilution. Assuming that the mar- 

 shalling of the ions in solution corresponds with the 

 arranp-ement of the atoms in the crystallised electro- 

 lyte, (he author derives an expression for the charac- 

 teristic potential in terms of the ionic charge, the 

 dielectric constant of the medium, and the dilution of 

 the solution. By introducing the Clausius virial 

 theorem, the connection between the proportion of 

 free ions ;ind the osmotic ratio is deduced, and this 

 relation differs notablv from the well-known equation 

 hased on the .Arrhenius theory. Experimental data 

 relative to the influ'^nce of concentration, temoerature, 

 and solvent on the conductinp' ]X)wer of strong 

 electrolvtes are shown" to be in accord with the 

 author's hvpothesis, which is developed in the last 

 pap°r of the series so as to account for the abnormally 

 lii"-h speeds of the hydrogen and hydroxvl ions, for 

 Avhich no satisfactory explanation has yet been given. 



THE FISHERIES AND THE INTER- 

 NATIONAL COUNCILA 



IT. 

 "\X^E now come to the consideration of the hvdro- 

 ' * graphical. meteorolo.'«ical. and physical work of 

 the International Council in relation to the fisheries 

 -nroblems pnt before it. Out of a total of seventv 

 fascicules of the '" Publications de Circonstance," no 



1 From a 'ertn'-e eivn in AberHeen on i\[arrh 4 by Prof. Mcintosh, 

 F.R.S. Continued from p. ^sS. 



XO. 2593, VOL. 103] 



fewer than thirty-one belong to this section, and this 

 in an inquiry specially devoted to the food-fishes. 

 Besides, there is a great bulk of large quarto hydro- 

 graphic and planktonic volumes which far exceeds 

 anything else in the Council's publications. The special 

 value of these to hydrographers does not concern the 

 present criticism, but considerable dubiety surrounds 

 the attempt to connect, for instance, oceanic currents 

 with the eggs, larvae, and young of the fishes, 

 especially when, in their own words, such give.s "some 

 notion of how verv complicated the question of the 

 passive movements of the pelagic stages under the 

 influence of the currents really is, and how it assumes 

 a different form in each species." This viev^^ takes 

 for granted that the larvae and young are as passive 

 as the eggs — a supposition dealt with long ago. 

 Secondly, in other words, there are special currents 

 which keep and carry the eggs and larvae of the 

 haddock annually to deep water, and others which 

 bear with unfailing regularity the young cod shore- 

 wards; likewise others, with similar annual rhythm, 

 sweep the larval and post-larval frog-fi.shes from their 

 floating ribands of gelatinous mucus to deep water, 

 along with such vagrant larvae of the skulpin as 

 have been hatched near the shore ; still others which 

 take the young plaice during the change of the eye 

 to the beach and. with nice discrimination, leave the 

 long rough dabs and a number of dabs in deep water 

 in the neighbourhood of their birthplace. 



It would be interesting to inquire for the special 

 currents which distribute the young of the viviparous 

 Norway haddock in the open water, or for those which 

 pass bv the voung of the viviparous blenny in the 

 rock-pools, or, by wav of varielv, for those motionless 

 waters which leave the young herrings, like a carpet 

 of threads, over square miles of the inshore waters, 

 and for those soecial currents which invariably plant 

 the voung wolf-fishes, after their escape from the 

 huge masses of large adhesive eggs, on rough ground. 

 The hydrographers have, moreover, overlooked the 

 "currents" which carry fishes and invertebrates 

 hatched on the bottom to the surface of the water, 

 and those, when they are older, which carry them 

 down again. They have missed those discerning 

 currents which, in the case of the ubiquitous pelagic 

 eggs of the rocklings, convev some shorewards and 

 send others to the deeper water. Moreover, thev have 

 forgotten the variable action of the winds in mo(lif\- 

 in.'^ the currents. 



Briefly, each species would thus appear to have a 

 current to itself and adapted to its special needs — a 

 supposition which cannot be accepted. The case of 

 the North Sea Bank is given, in illustration, as a 

 spawning area from which the small larvae are dis- 

 tributed over the whole deep part of the Skagerak, the 

 Norwegian channel and sea. It is stated that " tvoical 

 tidal movements have been demonstrated in the North 

 Sea. the resultant movement of which is often different 

 in the different depths. This might oossiblv be suffi- 

 cient to separate the eggs in one laver from those 

 in the other. For the rest, this disposition is natnrallv 

 verv different in the different parts of the North Sea." 

 Such uncertain groping for an anchorage of an im- 

 portant science in the fisheries is unworthy of it. 

 Support is drawn bv the Council from Jobs. Schmidt's 

 observations in Iceland, alreadv mentioned, but these 

 might readilv be interpreted otherwise. An interesting 

 local case, however, is that of the .\tlantic current in 

 the Baltic Sea, where it forms an intermediate one 

 between the ton and the bottom, and. it is said, the 

 ertgs of plaice have alone been found in it as far as 

 Bornholme. The adults pass higher up. but it is 

 suggested that thev come back to spawn there. These 

 observations would require confirmation, and, in any 

 case, cannot hold for the plaice of the North Sea 



