T 



July 7, 1923] 



NA TURE 



21 



during the quiet hours of the night. In three years 

 he recorded 22 cases of the disturbance of pheasants. 

 On seven occasions the birds crowed before the tremor 

 was felt, on five at the same time, and on five after- 

 wards. In four cases they crowed while no tremor 

 was felt, though slight movements were recorded by 

 the seismographs ; and in only one case did an 

 earthquake occur without the accompaniment of 

 pheasant-crowing. Thus, in half the cases observed, 

 the movement was noticed by pheasants more readily 

 than by a trained observer under good conditions. 



North Sea Fisheries in 1920-22. — There was 

 something unusual in the physical conditions of the 

 North Sea in 1920-22. A much greater influx of 

 Atlantic water occurred, and the pelagic fauna 

 showed marked deviations from its normal character. 

 The pelagic tunicate, Salpa, appeared in great 

 numbers, and there were swarms of medusae in regions 

 where they had not usually been seen in quantity. 

 The herring fishery of 1921 was very poor, both as 

 regards the catches made and the quality of the 

 fish. The latter were ill-nourished, and this may be 

 regarded as an indirect effect of the changed physical 

 conditions. Several papers that have appeared 

 recently provide data for a treatment of this remark- 

 able hydrographic occurrence. Rapports et Proces- 

 Verhaux, vol. xxix., published in May by the Inter- 

 national Council for Fishery Investigations, gives 

 the first report of a committee formed to investigate 

 the Atlantic slope W. and S.W. from the British 

 Isles, and hydrographic and planktonic results for 

 the year 1921 are recorded. Publications de Cir- 

 constance, Nos. 78, 79, and 80, also published by the 

 Council (in April), contain papers by A. C. Hardy, 

 J. N. Carruthers, and J. R. Lumby, dealing with 

 the plankton, the non-tidal movements of North Sea 

 water, and the salinity and temperature of the 

 southern North Sea and English Channel during 

 192 1. The results are interesting and of importance 

 for a consideration of the causes of the unusual 

 conditions of the North Sea mentioned above. That 

 inadequate food-supply does not completely explain 

 the failure of the herring fishery of 192 1 is apparent 

 from results obtained by Mr. B. Storrow (Report 

 of the Dove Marine Laboratory, Cullercoats, 

 Northumberland, for 1922). There was an actual 

 shortage of fish having three winter rings on their 

 scales ; this result was obtained from a great number of 

 careful measurements made at Cullercoats. There- 

 fore, whatever happened to make the fishery a failure 

 happened about 191 7 as well as in 192 1. The failure 

 characterised the North Sea fishery but not that of 

 the Firth of Clyde, and there the 191 7 year class of 

 fish was well represented. 



Constitution of Dolomite. — Dolomite has always 

 been regarded by mineralogists as a definite com- 

 pound, CaCOs.MgCOg, the reason for this conclusion 

 being apparently the very constant composition of 

 different specimens of the mineral from various 

 parts of the world. The suggestion has recently 

 Jieen made by Spangenberg that the mineral is a 

 solid solution of calcite and magnesite, the limits of 

 miscibility being placed between the proportions 

 CaC03,2MgC03 and 2CaC03,MgC03. The substances 

 prepared by him, however, have not the properties 

 of dolomite. The matter has recently been investi- 

 gated by Mr. A. E. Mitchell, at the suggestion of 

 Prof. Donnan, and the results of some preliminary 

 experiments are given in the May issue of the Journal 

 of the Chemical Society. The dissociation pressure 

 curves of calcite, magnesite, and dolomite have been 

 determined from 700° to 1200°. In the case of 

 calcite it is shown that the equation of Nernst is 



NO. 2801, VOL. 112] 



in good agreement with the results, the more com- 

 plicated equation of Johnson being not only un- 

 necessary but inaccurate. The curve for dolomite 

 lies about half way between those of calcite and 

 magnesite. Some measurements of the specific heats 

 were made, in order to apply the Nernst equation, 

 and an attempt to measure the heat of formation 

 of dolomite gave the small value of 4-52 kg. cal. per 

 mol. It is concluded that the dissociation of dolomite 

 occurs according to the equation CaCOg.MgCOs 

 = CaO,MgO -I-2CO.2. The experiments have not, 

 however, been carried far enough to enable a decision 

 to be made as to whether dolomite is a compound 

 or a solid solution. 



Moisture in Freshly Felled Timber. — In the 

 Notes of the Royal Botanic Garden, Edinburgh, 

 for January 1923, Prof. W. G. Craib has a third 

 paper upon the " Regional Spread of Moisture in the 

 Wood of Trees." As described in the earlier papers, 

 specially selected trees are carefully felled and 

 sections of timber taken for investigation, moisture 

 determinations being separately carried out for 

 blocks at different depths right across the section ; 

 this process is repeated at different levels and the 

 results expressed graphically. This interesting line 

 of research not only provides data of great practical 

 interest to the forester, but also contributes to our 

 knowledge of the ascent of sap in trees. Prof. 

 Craib has previously shown that in winter there 

 appears to be considerable storage of sap in the 

 heart-wood of Acer Pseudoplatanus, the sap moving 

 outwards later until it is mainly in the outer ring 

 of young wood as the transpiration current becomes 

 active in the summer. The present paper demon- 

 strates a somewhat similar but slower change of sap 

 distribution in the wood of the holly, while in resinous 

 conifers no storage of sap in the heatt-wood takes 

 place, probably because the resin hinders radial 

 migration of the sap. In the non-resinous yew tree 

 there is again a storage of sap in the heart-wood. A 

 very interesting plate shows the distribution of sap 

 in a tree of Populus trichocarpa, felled on a windy 

 day. In the sapwood on the side towards the wind 

 there is the usual high percentage of moisture, but 

 on the side away from the wind it has fallen very 

 low. Prof. Craib 's further papers will be awaited 

 with interest, and there will be general congratula- 

 tions from his colleagues that this paper seems to 

 show him well on the way to a full renewal of the 

 scientific activities so severely interfered with by his 

 accident at the time that the British Association 

 met in Edinburgh. 



Ewing's New Ferromagnetic Model. — In our 

 issue for March 9, 1922, p. 321, we gave an account of 

 the new model of an atom of a ferromagnetic material 

 proposed by Sir Alfred Ewing as an improvement on 

 that brought forward by him in 1890. A portion only of 

 the atom was taken as capable of alignment with the 

 external field, and the controlling force on this part 

 was considered to be due in the main to the fixed 

 portion of the atom. In the February issue of the 

 Science Reports of the University of Sendai, Profs. 

 Honda and Okubo examine the new theory, and show 

 that it is not in agreement with the discontinuous 

 changes of magnetic properties which are found in 

 steels during heating and cooling between 700° and 

 730° C, nor with those found in pure iron at 910° 

 and 1410° C. respectively. They conclude that the 

 quantitative extensions of the older theory made by 

 them in 191 6 and 191 7 reproduce the hysteresis loop 

 and the effects of temperature on magnetisation much 

 more accurately than does the new theory. 



