April 



D> 



1917] 



NATURE 



119 



icali metals, like the other metals previously 

 examined, form metallo compounds isomeric with 

 normal salts, and that, therefore, these metals maj' 

 -ume a valency higher than that usually exhibited 

 them. A class of compounds intermediate between 

 :he metallo and normal salts also exists. These are 

 icrmed metallato compounds. The possibility of most 

 metals, other than carbon and hydrogen, assuming a 

 valency value higher than that usually exhibited by 

 them is shown to explain (i) the constancy in the heat 

 of substitution of CH, for H as contrasted with want 

 of constancy in the case of the substitution of OH or 

 Ci for H ; (ii) the fact that the heat of neutralisation of 

 ' rifanic acids is lower than that of inorganic acids, 

 d exhibits certain distinctive features when only 

 rtially effected ; (iii) that all true acids must contain 

 doubiy linked oxygen atom, and that the apparent 

 -:eptions to the constancy of the heat of neutralisa- 

 ■ a are due to the acid not being a true acid; (iv) that 

 - so-called normal salts of the alkali metals with 

 -^anic acids are strongly alkaline, and that those with 

 ■rganic acids are feebly so,- (v) that the usual method 

 titration of an acid b}- an alkali, as well as the 

 ■cipitation of the acid or base by usual methods, 

 rails in the presence of an organic acid; (vi) that the 

 actual value of the heat of neutralisation constant can 

 ' explained.— Prof. E. Wilson and Prof. J. W. 

 Nicholson : Residual magnetism in relation to magnetic 

 ielding. (i) The paper contains a further contribu- 

 ■ n to the study of the problems presented by the 

 cessity for constructing a magnetic shield capable 

 reducing the earth's field to an order as low as 

 ■01 C.G.S. unit in a large space. Themain problem 

 c treated in earlier papers is that of residual mag- 

 tism in the various shells of the shield, and this 

 oblem is discussed in connection with exhaustive 

 ;)eriments in the presenc paper, (ii) It is found that 

 ■:• ordinary' process of demagnetisation of a mass of 

 ■n fails to be completely efiective if, during the 

 eration of the current which is diminished by steps 

 id continually reversed, a constant magnetic field 

 -uch as that of the earth is present at the same time. 

 This phenomenon has escaped notice hitherto, probably 

 n account of the smallness of the earth's field, but 

 becomes prominent in experimental work involving 

 ■ measurement of fields so small as that specified 

 i\\. (iii) This effect of the steady magnetic field is 

 (wn to be associated with a reversal of the residual 

 U'Cts of hysteresis in iron when tested in the earth's 

 • Id by currents lying within a certain range in which 

 tiiey approximately annul the field, (iv) It has been 

 found possible to ensure complete removal of irregular 

 polarisation or previous magnetic history of the shells, 

 provided that during the preliminary demagnetisation 

 of the shells the earth's steady field on them is annulled 

 by a steady current of suitable amount enclosing the 

 whole shield, (v) The well-known fact that iron, 

 polarised by a large force, and afterwards tested for 

 permeability at a lower force, shows diminished per- 

 meability at the lower force, gives, in combination 

 with these results, an interpretation of the increase of 

 permeability manifested by iron when tested within a 

 magnetic shield. — Dr. S. Chapman : The solar and lunar 

 diurnal variations of terrestrial magnetism. 



Zoological Society, March 20. — Dr. \. Smith Wood- 

 ward, vice-president, in the chair. — E. P. Allis, Jr. : 

 The prechordal portion of the chondrocranium of 

 Chimaera coUiei. — D. M. S. Watson : A sketch- 

 classification ot the pre-jurassic Tetrapod vertebrates. 

 The classification introduced in this paper is founded 

 on a detailed consideration of all parts of the skeleton 

 of such old amphibia and reptiles as are at all well 

 known. In previous papers the author has analysed 

 the features presented by many of these forms, dis- 

 tinguishing between those which are common to all 

 NO. 2475. VOL. 99I 



early reptiles and those which are restricted to definite 

 stocks, the latter being divided into those dependent 

 on "adaptive radiation " and the more fundamental 

 characters, especially those of the brain-case and ear, 

 which are not to be correlated with any special mode 

 of life. These non-adaptive characters, which appear 

 Jh typical forms even in early members of a stock, 

 serve for the ordinal and superordinal grouping, 

 adaptive changes being used for groups of lower 

 order and the gradual loss of primitive structures 

 giving horizontal dividing lines. 



Dublin. 

 Royal Dublin Society, March 27.— Prof. Hugh Ryan 

 in the chair, — Prof. W. Brown : The change in Young's 

 modulus of nickel with magnetic fields. The change 

 is smaller for alternating than for direct longitudinal 

 magnetic fields. With transverse magnetic fields, both 

 direct and alternating, the Young's modulus first 

 increases, then decreases ; and the magnetic field in 

 which the maximum value occurs is smaller the 

 greater the constant load on the nickel wire. 



Paris. 

 Academy of Sciences, Februarv' 26. — M. A. d'Arsonval 

 in the chair. — E. Aries : The entropy of perfect gases 

 at the absolute zero of temperature. The entropy at 

 the absolute temperature is not - 00, but is in the 

 indeterminate form of two infinite quantities of 

 opposite signs. It is shown that for a gram-mole- 

 cule of a solid, the increase in the entropy, when 

 vaporising entirely at a low temperature as a perfect 

 gas, tends towards the gas constant R, as the tem- 

 perature apfH-oaches the absolute zero. — P. Vuillemin : 

 Eurotittm amstelodami, suj^K)sed parasite of man. — 

 Henri Lecomte was elected a member of the section 

 of botany, in the place of the late Ed. Prillieux. — G. 

 Julia : Binary forms of any degree. — P. Ganbert : A 

 new property of sphaerolites. — L. Gentil : The Upper 

 Marine Miocene of West Algeria. — M. Stuart-Menteath : 

 The interior basins of the Pwenees. — M. Miege : New- 

 attempts at the disinfection of the soil. The anti- 

 septics used included toluene, carbon bisulphide, hy- 

 drogen peroxide, lysol, formol, potassium perman- 

 ganate, copper sulphate, sulphur, bleaching powder, 

 and wood charcoal. In large-scale experiments, tolu- 

 ene and carbon bisulphide proved the most efficacious, 

 as regards both increased yield and the health of the 

 plants. — M. Weinberg and P. Segnin : Study on gas 

 gangrene. B. oedematiens and anti-oedematietts 

 serum. 



March 5. — M. A. d'Arsonval in the chair. — 

 A, Lacroix : The phonolitic rocks of Auvergne. 

 A delicate case of interpretation of the chemical 

 composition of felspathoid rocks.— G. Bigourdan : 

 Some seventeenth-centur\- obser^•atories in the 

 provinces. Historical details are given of La Fleche, 

 Le Maurier, Loudun, and Aries.— G. Giraud : Hyper- 

 fuchsian functions and systems of total differential 

 equations. — E. Cotton : Characteristic number and 

 radius of convergence. — R. de Montessus de Ballore : 

 Left algebraic curves,— E. Belot : The possible role of 

 volcanoes in the |M-oduction of meteorites. — J. 

 Gnillaume : Observations of the sun made at the 

 Observatory of Lyons during the fourth quarter of 

 19 16. Observations were made on sixty-four days 

 during the quarter, and the results are given in tables 

 showing the number of spots, their distribution in 

 latitude, and the distribution of the faculae in lati- 



I tude. A. Berget : A differential refractometer for 



measuring the salinitv of sea-water. The two liquids 

 to be compared are placed in a rectangular box 

 separated into two parts by a diagonal glass parti- 

 tion. An image of a slit, after passage through this 



1 double prism, is focussed in a microscope, and the 



