June 15, 1916] 



NATURE 



335 



colloidal solutions. The author, in reply to some 

 remarks made by Mr. W. B. Hardy in the course 

 of his Guthrie lecture, points out (a) that no viscosity 

 formula can cover the stage of gel formation, since 

 the change from a liquid with only slight anomalies 

 to a system having many properties of an elastic solid 

 necessarily precludes this, and (6) that the formula 

 given by Einstein, and, independently by himself, for 

 the viscosity of a suspension of rigid spherical par- 

 ticles, does not in any event apply to systems such 

 as discussed by Mr. Hardy, which belong to the class 

 known as emulsoids. 



Linneaii Society, June i. — Sir David Prain, presi- 

 dent, in the chair. — C. Reid and J. Groves : New types 

 of fossil Characeae from the Purbeck Beds. The 

 earliest known remains of undoubted Characeae were 

 detached fruits recorded from the Lias and Oolite, 

 the earliest remains of the vegetative parts being 

 those in the Middle Purbeck Beds. By subjecting 

 slices of the limestone, in which the plants were 

 found, to a prolonged drip of very slightly acidulated 

 water, so that the Chara-remains were etched out, 

 the authors had been able to elicit much fresh in- 

 formation as to structure, which had not been obtain- 

 able from the sections and polished surfaces of chert 

 —Prof. G. E. NichoUs : The structure of the vertebral 

 column in the Anura phaneroglossa and its importance 

 as a basis of classification. — Prof. J. MacLeod : Ouan- | 

 titative variation in certain diagnostic characters of i 

 ten species of the genus Mnium. Is it possible to j 

 describe and to identify an animal or a vegetable ;' 

 species by means of numbers representing the value I 

 of the specific characters? The author has tried to j 

 realise this by measuring thirty-eight characters in j 

 about ninety species and twenty varieties of the genus | 

 Carabus. The war prevented him from finishing and 

 publishing his work. He tried to carry out similar 

 work with plants, taking mosses of the genus Mnium. 

 He limited himself to the study of the leaves of the 

 fertile stem of ten species of that genus. When the 

 length of the successive leaves from the base to the 

 summit of a fertile stem of a Mnium is measured it 

 is seen that the length increases uo to a maximum 

 and then diminishes. This curve represents the varia- 

 tion of the character under consideration along the 

 axis. This peculiar form of variation mav be called 

 gradation. The gradation of the measured characters 

 of the ten species of Mnium shows much diversitv. 

 In these examples it is possible to find the name by 

 four characters ; but it may be necessary- to use five 

 or more characters. As a dozen characters are avail- 

 able, it is honed that the identification of a ^iven 

 specimen will be always oossible, even if thf» species j 

 were more numerous. ^V. L. Distant : The Rhvncota I 

 from the Indian Ocean. j 



Dublin. I 



Royal Irish Academy, May 22.— The Most Rev. Dr. I 

 Bernard, Archbishop of Dublin, president, in the chair. | 

 — J. Algar : Diketones derived from diacetoresorcinol- 

 dimethylether. The diketone dianisovlacetoresorcinol- 

 dimethylether is obtained by the condensation of ; 

 diacetoresorcinoldimethylether with anisic ester by 

 means of sodium. Similar diketones may be obtained 

 by the condensation of the dimethylether with the 

 esters of phenylacetic, acetic, and oxalic acids. Di- 

 acetylacetoresorcinoldimethylether and di-a-phenyl- 

 acetylacetoresorcinoldimethylether are colourless crystal- ■ 

 line substances, while dianisoylacetoresorcinoldimethyl- 1 

 ether is coloured slightlv yellow, and dimethoxytso- ' 

 phthaloyldipyruvic, ethylester is coloured strongly ' 

 yellow. These diketones on heating with concen- | 

 trated hydriodic acid should give dichromone or di- 1 

 flavone derivatives. In the condensations with anisic j 



NO. 2433, VOL. 97] 



and phenylacetic esters the yields of the diketones 

 were insufficient to try this reaction. Diacetylaceto- 

 resorcinoldimethylether on heating with hydriodic acid 

 gave a tarry product, from which an extremely small 

 amount of colourless substance was isolated, which 

 dissolved in concentrated sulphuric acid, giving a solu- 

 tion with the strong green fluorescence characteristic 

 of chromone derivaties. This colourless substance was 

 probably a dichromone derivative. 



P.ARIS. 



Academy of Sciences, May 29. — M. Camille Jordan in 

 the chair. — The President gave an account of the 

 scientific work of the late General J. S. Gallieni, 

 correspondant in the section of geography and navi- 

 gation.— G. Bigonrdan : Joseph Gaultier and the dis- 

 covery of the visibility of the stars in full daylight. 

 This discovery has been in turn attributed to Picard 

 (1668), Morin (1635), Hortensius (1633), Schickhardt 

 (1632). It is shown that this discover}.- was made in 161 1 

 by Joseph Gaultier, of Aix-en-Provence (see p. 328). — 

 P. Dnhem : The general theorj' of electric oscillations. — 

 M. Balland : An unpublished letter of Parmentier. The 

 letter is dated August 13, 1800, and has reference to 

 the quality of the bread supplied to the Hotel des 

 Invalides. — B. Globa-Mikhailenco : The movement of a 

 billiard ball with sliding and rolling friction. — M. 

 Mesnager : All points of a supported thin rectangular 

 plate are lowered on the application of a uniform 

 load, no element remains horizontal, the lines of 

 greatest fall all end at the centre. — C. Stormer : The 

 integration of a system of differential equations met 

 with in the study of a cosmical problem. The equa- 

 tions occur in the problem of finding the motion of 

 an electrified corpuscle in the field of an elementar}- 

 magnet, supposing the corpuscle to be also submitted 

 to the action of a central force emanating from the 

 magnet and inversely proportional to the square of 

 the distance. — Ed. Sarasin and Th. Tommasina : The 

 proof of a third Volta effect and the experimental 

 confirmation of the given explanation. — F. Zambonini : 

 The relations which exist between the angles of 

 mixed crystals and those of their components. The 

 mixed crystals studied included the molybdates of 

 lead and cerium, calcium and cerium, strontium and 

 cerium, lead and didymium, calcium and didymium, 

 calcium-yttrium-cerium, and the tungstates of calcium 

 and cerium. In nearly all the cases studied there 

 was no precise relation between the values of the 

 angles and the composition. — P. Fallot : The presence 

 of the Aptian in the sierra of Majorca. — C. Sanvagean : 

 The heterogamic sexuality of Alaria esctilenta. — J. 

 Amar : The functional value of the mutilated limbs. — 

 Ch. J. Gravier : The Actinean fauna of the island of 

 San Thome (Gulf of Guinea). — A. TriUat and M. 

 Fouassier : Study of some factors exercising an influ- 

 ence on the rapiditN- of evolution of the t\-phoid bacillus 

 in milk. 



Cape Town. 



Royal Society of South Africa, April 19. — Dr. L. 

 Peringuey, president, in the chair. — -Sir T. Mnir : Note 

 on pfaffians connected with the difference-product. In 

 addition to the discovery- of the connection referred 

 to in the title, there is established a series of theorems 

 bringing pfaffians into relation with permanents and 

 other integral functions. — Sir T. Muir : Note on the 

 so-called Vahlen relations between the minors of a 

 matrix. The paper contains a critical examination of 

 the relations in question, and an attempt to put the 

 subject on a sounder basis. There is also incidentally 

 involved a rectification of the statements hitherto 

 accepted regarding the histon,- of the subject. — R. T. A. 

 Innes : The development of the perturbative function 

 in the theor>' of planetary' motion. The author has 



