December 27, 1917] 



NATURE 



;39 



Physical Society, November 23.— Mr. W. R. Cooper, \ 

 vice-president, in the chair. — Prof. J. W. Nicholson : j 

 Some problems of stability of atoms and molecules, j 

 The paper is mainly concerned with the possible exist- 

 ence and stability of atoms, and of molecules formed 

 atter the manner sug'fjested bv Stark, the link between 

 the atoms in a molecule being provided by a stationary 

 electron on the molecular axis. Atoms on the Ruther- 

 ford model, though dynamically unstable, are stable for 

 the simple vibrations ordinarily excited; but it is shown 

 in the paper that atoms with such a stationary electron 

 have a much more limited degree of stability. More- 

 over, they cannot exist even in an undisturbed state 

 unless they are endowed with a negative charge, for no 

 steady motion is possible, and this conclusion extends 

 even to atoms regulated according to a dynamics such 

 as that of Bohr. Stark's conclusions do not, therefore, 

 survive a quantitative treatment,, and molecules cannot 

 be formed in the manner he supposes. The paper also 

 discusses the more symmetrical problem, in which there 

 are two such stationary electrons in an undisturbed 

 atom, and it is shown that systems with a transitory 

 existence, which are known by their spectra to occur 

 in the solar corona, are apparently unaccompanied by 

 the still more transitory systems which would be formed 

 bv the attachment of an electron after the manner of I 

 Stark. This is a further argument against the possi- I 

 bilitv that two atoms in a molecule can be linked by a 

 single electron, or bv two electrons, which attract both 

 atoms. — T. H. Blakesley : Uses of certain methods of 

 classification in optics. This consisted of an account of \ 

 the additions which, in the course of the intervening 

 vears, the author had been enabled to make in the 

 general diagram of optical properties, first communi- 

 cated by him to the Physical Society in the year 1903 

 (Proceedings, vol. xviii., p. 591). 



Geological Society, December 5. — Dr. Alfred Harker, 



President, in the chair. — E. Heron-Allen and J. E. 

 arnard : Application of X-rays to the determination of 

 the interior structure of microscopic fossils, particu- 

 larly with reference to the dimorphism of the Nummu- 

 lites. Mr. Heron-Allen said that in the year 1826 

 d'Orbigny published among the nomina nuda that 

 compose his "Tableau M^thodique de la Classe 

 C^phalopodes " the name Rotalia dubia. G. Berthelin 

 was the first investigator to make use of the " Planches 

 inedites " which had been partly completed by 

 d'Orbigny for the illustration of his unpublished work 

 upon the Foraminifera. Berthelin made for his own 

 use careful tracings of 246 of A. d'Orbigny's un- 

 finished outline-sketches ; among them was the sketch 

 of R. dubia. On the death of Berthelin the tracings 

 passed into the possession of Prof. Carlo Fornasini, of 

 Bologna, who reproduced them all between the years 

 1898 and 1908. Fornasini 's opinion was that the 

 organism depicted bv d'Orbigny was probably referable 

 to the Ostracoda. Messrs. A. Earland and E. Heron- 

 Allen, while examining the material brought by Dr. 

 J. J. Simpson from the Kerimba Archipelago in 1915, 

 discovered undoubted Foraminifera of an unknown 

 tv'pe, which resembled Berthelin 's tracing. Prof. 

 Boule sent the d'Orbigny type-specimen to London, 

 and the Rhizopodal nature of R. dubia was estab- 

 lished. It is not a Rotalia, and it must await deter- 

 mination until more specimens are obtained. It has 

 been named provisionally Pegidia papiV.ata. Mr- 

 Barnard experimented with the object of ascertaining 

 the interior structure of the shell by means of the 

 X-ravs. A skiagraph of the dense test of Biloculina 

 htilloides, d'Orb., shows the arrangement of the earlier 

 chambers as clearly as it is indicated in Schlum- 

 berger's sections. The application of X-rays to the 

 dense imperforate shells, Corntisjyira foliacea (Philippi), 



NO. 2513, VOL. 100] 



produced skiagraphs showing the dimorphism of the 

 shells. The skiagraph of Astrorhiza arenaria, Nor- 

 man, shows the internal cavities that contained the 

 protoplasmic body. Two arenaceous forms, BotelUna 

 labyrinthica, Brady, and Jaculella obtusa, Brady, are 

 distinguished at once by skiagraphs. Mr. Barnard 

 afterwards experimented on still more difticult mate- 

 rial. Operculina complanata, Def ranee, the umbilical 

 portion of which is obscured by secondary shell-sub- 

 stance, furnished a skiagraph that showed curious dis- 

 tortions of the internal septa. The determination of 

 the Nummulites, depending on a knowledge of the 

 internal structure, is facilitated by the application of 

 X-rays. 



Optical Society, December 13. — Prof. F. J. Cheshire, 

 president, in the chair .--J. W. French: Proposed 

 standard system of optical notation and sign conven- 

 tion. The author pointed out tl^at owing to "the non- 

 existence of standards, confusion often arises in the 

 interpretation and use of optical formulae, due to in- 

 definiteness as to the sign convention employed in 

 their construction. The suggested scheme, which con- 

 tained about one hundred clauses, dealt with the nota-. 

 tion for points, lengths, and angles and the sign con- 

 vention for lengths and angles. Certain of the quan- 

 tities were dealt with historically, as, for example, 

 the substitution of the Greek letter "/x" for "n," to 

 represent a refractive index. It was suggested that 

 the more controversial clauses might be discussed by 

 a committee which would issue supplementary lists 

 that would ultimately cover all points, including the 

 definition of terms and other standards. — T. Smith : 

 Optical nomenclature and symbolism. The author 

 dealt with the definitions of fundamental quantities, 

 and conventions for positive directions, angles, curva- 

 tures, and powers. The necessity for a number of 

 new symbols was shown; a special symbolism was 

 required for oblique pencils. The new symbols pro- 

 posed for frequently recurring quantities were ex- 

 plained. 



Linnean Society, December 13.— Sir David Prain, 

 president, in the chair.— Capt. A. W. Hill : Seeds en- 

 closed in a stony endocarp and their germination. In 

 certain genera the seed or seeds are protected by inclu- 

 sion within a stony endocarp. In such cases it is 

 found that definite provision is made during the de- 

 velopment of the fruit for the liberation of the seeds on 

 germination from their stony envelope. In the case of 

 Prunus and similar normally one-seeded fruits splitting 

 apart of the two halves of the endocarp takes place, but 

 in such three- to five-seeded fruits as Canarlum, Sclero- 

 carya, Dracontomelon, Saccoglottis, Aubrya, etc., special 

 fenestrae or opercula are provided which are pushed 

 awav by the germinating embryo. In Davidia not only 

 are special fenestrae removed, but also portions of the 

 intervening skeletal structure of the endocarp. The 

 remarkable fruit of Pleiogynium encloses several seeds 

 which germinate without anv disintegration of the 

 endocarp.— Mrs. Haig Thomas: Skins illustrating re- 

 sults obtained in crossing species of pheasants. The 

 cross between silver pheasant (Gennaeus nycthcmerus) 

 and Swinhoe's pheasant (G. swinhoei) gave a remark- 

 able series of segregating forms in the Fj generation. 

 Amongst these were birds scarcely distinguishable from 

 swinhoei. The F, form was a combination very dis- 

 tinct from the parental types; and, judging from the 

 freauency with which sorne of the new forms occurred 

 in Fo, it was evident that they behaved as dominants 

 and likely that thev could have been bred true. The 

 cross Phasianus versicolor x P. fonnosanus had been 

 made reciprocally. Crosses involving several pairs 

 showed that there were consistent differences according 

 to the wav in which the cross was made. 



