January 19, 191 1] 



NATURE 



395 



n.irvr an account is given (i) of improvements in the 

 leness and parallelism of the standards ; (2) of changes 

 oduced in the author's measuring machine to cope 

 1 the more accurate standards. It is easy to get con- 

 :nt readings of length provided the standard is not 

 . ed ; but if, as is required, the standard is moved, it 

 L difficult mechanical problem to provide a movement 

 ^- nearly parallel that the readings before and after move- 

 ment shall be consistent. Curves and tables are given 

 ?h.>\ving the degree of accuracy at present obtained. A 

 It advance in refinement is expected on the present 

 5 of work. 



Linnean Society, December 15, 1910. — Dr. D. H. Scott, 

 1 R.S., president, in the chair. — Dr. O. Stapf : Report 

 the International Botanical Congress, held at Brussels 

 May 14—22, 1910. The Linnean Society ap{x>inted five 

 gates for the congress with the view of having the 

 rent departments concerned in the discussion on taxo- 

 lic nomenclature so far as possible represented. The 

 gates were Messrs. Arber (fossil plants). Cotton (algae, 

 ens, and fungi), Gepp (MUsci and Hepaticae), Henr\" 

 ves and Dr. Stapf (phanerogams and vascular crypto- 

 s, and Mr. H. Groves also Charceae). Phytogeography 

 - not taken especially into account, as Mr. Tansley, 

 delegate of the Cambridge Philosophical Society, joined 

 ::on iii. — R. W. H. Rowr : Non-calcareous sponges 

 n the Red Sea, collected by Mr. Cyril Crossland. The 

 ~^nt report contains descriptions of seventy-seven 

 ies, belonging to fort\-four genera, of which thirty- 

 species and four genera are new to science. The 

 1 sponge fauna of the Red Sea now includes no fewer 

 1 187 species, but this includes certain forms only 

 'd in the Gulf of .Aden. The Red Sea sponge fauna 

 vs a very great similarity' to that of the Indian Ocean, 

 ewer than eighty species being found common to the 

 regions. Of these eighty species, sixteen occur along 

 coasts of East Africa or on the islands near by, twentv- 

 • occur in Ceylon, and no fewer than thirtj-one in the 

 : Indies and Australia. As a result, the Indo- 

 ralian region, as defined in the report on the 

 axonia of the Challenger expedition, has been enlarged 

 include the whole of the Indian Ocean and the adjacent 

 seas, and it is suggested in this report that a division 

 into western and eastern areas can be made along the 

 sixty-fifth meridian of east longitude. The fauna of the 

 Red Sea, not only as regards sponges, but in general also. 

 '■ ^-s a very close relationship both in character and 

 :es with that of East Africa, and that of Ceylon with 

 Australian fauna. .Another interesting feature of Mr. 

 Crossland 's collection is the presence of three species 

 previously only known from the Mediterranean area, or, 

 at any rate, the North .Atlantic. It is suggested that 

 these forms have migrated thence into the Red Sea 

 through the Suez Canal. — R. S. Adamson : Notes on the 

 comparative anatomy of the leaves of certain species of 

 Veronica. Thirty-eight species of the genus, natives of 

 New Zealand, have been examined, which show great 

 variation of form. .All are more or less xerophilous and 

 evergreen. One of the most noticeable features is the 

 formation at the leaf-insertion of a patch of cork-cells 

 which completely cuts off the continuity of tissues except 

 for the bundle ; these cells are formed by a phellogen. and 

 may appear in the first year of the three during which the 

 leaf persists. The species show, in general, a series of 

 increasingly xerophilous types of leaf structure, from 

 forms with large leaves with normally differentiated meso- 

 phyll, through those with quite hom<^eneous structure, lo 

 forms with scale-like leaves with corresponding anatomical 

 modifications. The less xerophilous species have hyda- 

 thodes at the leaf-apex that may be modified in various 

 ways ; these are absent in the more xerophilous forms. 

 Stomata are protected in various ways, especially bv 

 cuticular expansions over the pore, and bv deoression of 

 the guard-cells below the surface. The xerophilous nature 

 of the leaves can be correlated to some extent with the 

 climatic conditions in the native habitats. 



Mathematical Societv. Tanunrv t2.— Dr. H. F. Bj»k«*r, 



president, in the chair.— T.C. Lewis: .A property of the 



number 7.— Prof. E. W. Hobson : The fundamental 



theorem relating to the Fourier constants for given func- 



NO. 215 I. VOL. 85I 



tions. — Prof. H. M. Macdonald : The integration of the 

 equations of propagation of electric waves. — Dr. \V. H. 

 Young : The fundamental theorem in the theorv' of func- 

 tions of a comple.x variable. — Miss H. P. Hudson : The 

 3-3 birational transformation in three dimensions (second 

 paper). 



Paris. 

 Academy of Srien«^e8, lanuary o. — M. Armand Gautier 

 in the chair. — Emile Picard : A singular integral equa- 

 tion. — A. Laveran : The resistance of goats and sheep to 

 trypanosomiases : the long duration of acquired immunity 

 following these diseases. Both sheep and goats are 

 susceptible to most of the trypanosomiases, but the attack 

 is usually slight and followed by cure, whilst in most 

 other animals the termination is fatal. The serum of a 

 sheep two and a half years after cure from an attack 

 of T. dimorphon is active, and protects mice against the 

 attack of the same organism. Similar results were 

 obtained from the serum of the goat. — M. de Forcrand : 

 Some probable chemical properties of radium and its 

 ccMnbinations. From thermochemical data for the metals 

 of the alkalis and the alkaline earths, and the position 

 of radium in this series, thermochemical data are calcu- 

 lated for radium and its compounds. From these data it 

 is reasonable to assume that the hydroxide will be a little 

 more stable than bar\ta, but a little more easily dissoci- 

 able than sodium hydroxide ; the oxide RaO should be 

 easily converted into the peroxide RaO, at a red heat, and 

 radium carbonate should be decomposed with some diffi- 

 culty at a red heat. The existence of a hydride (RaH,) is 

 also predicted. — M. Luixet : The variable brightness of 

 certain stars of the tv'pe of 5 Cephei. On the basis of 

 certain assumptions, the changes in brightness are calcu- 

 lated, and the curves thus obtained compared with the 

 experimental data, with satisfactory' agreement. — Charles 

 Nordmann : The effective diameters of the stars. 

 Starting with the effective star temperatures determined 

 by the author's stellar photometer, the effective diameters 

 of ten stars are calculated. It is found that stars the 

 effective temperature of which are higher than that of 

 the sun have the smallest diameters, the contran.' holding 

 for stars cooler than the sun. — M. Le Fort : An interpola- 

 tion fomnula established with a view to some practical 

 applications. — M. Zietnbinski : The relation existing 

 between the thrust of a pronulsive helix when fixed and 

 when attached to a body in motion in the air. — Pierre 

 Weiss : A new pro(>erty of the magnetic molecule. If the 

 molecule Fe,0, in magnetite possesses four degrees of 

 freedom of rotation, the value of the specific magnetisa- 

 tion at the absolute zero will be 97-7, very near to the 

 value 95-9 obtained by Kamerlingh Onnes at the tempera- 

 ture of liquid hydrogen. FrtMn the experiments described, 

 it is found that at certain temperatures the magnetic 

 moment of the molecule increases suddenly by quantities 

 bearing a simple numerical relation to the magnetic 

 moment of the molecule at low temperatures. — L. 

 D^combe : The definition of entropy and of tempera- 

 ture. Monocyclic systems. — J. de KowraUski and J. 

 de Dzierxbickl : The influence of functional groups on 

 the spectrum of prt^ressive phosphorescence. The sub- 

 stances studied were examined in alcoholic solutions (con- 

 centration 0-05 normal) at about — 190° C. The acids 

 examined included benzoic, the three toluic, three amido- 

 benzoic. three oxybenzoic acids, and also benzonitrile and 

 /)-tolunitrile. — Witold Bronie«wski : The electrical proper- 

 ties of the aluminium-magnesium alloys. The experi- 

 ments included measurements of the electrical resistance, 

 thermo-electric power (against lead), and the variation of 

 the thermo-electric power with temperature, the data 

 obtained being given in the form of curves with the per- 

 centage of magnesium as abscissae. The probable exist- 

 ence of the compounds -AlMg and .Al.Mg, is indicated, 

 but the existence of Al,Mg and AlMg,. described bv earlier 

 workers on the same subject, could not be confirmed. — 

 Ed. Chauvenet : .A general method for the preparation 

 of anhydrous chlorides (see p. "^S^). — J. B. Senderens : 

 Ketones derived from the three isomeric toluic acids. The 

 method for preparing ketones, based on the catalytic action 

 of thoria. described by the author in a previous paper, has 

 been applied to the preparation of fifteen cresyl-al'-vl- 

 ketones. The densitv, boiling point, and melting --'^'nt 

 of the semicarbazone ^re "'ven for each ketone. — M. 



