December i6, 1915]* 



NATURE 



445 



ends of the tubes are covered with a cap provided with 

 an outlet and an inlet tube. Water enters the cap by 

 the inlet tube, and a weak solution containing the 

 diffused salt leaves the cap by the outlet tube. Time, 

 which may be as long as a fortnight, is allowed for 

 the attainment of the steady state, and an individual 

 experiment may last six weeks. The quantity diffused 

 is obtained by chemical analysis. In the case of a 

 solution containing 02237 gram of potassium chloride 

 to the cubic centimetre (a 3N solution) the " mean 

 diffusivity" with respect to water is 1703x10-' 

 (C.G.S. units) at a temperature of 185° C. 



Royal Astronomical Society, December 10.— Prof. R. A. 

 Sampson, president, in the chair. — H. H. Turner and 

 -Miss Blagg : Baxendell's observations of variable 

 stars; continuation, including T Herculis, R Leonis, 

 and S Orionis. — F. A. Bellamy : The number of fai.it 

 stars with large proper motions in zone +29°, and 

 on the accuracy of Hagen's chart of variable stars. — 

 H. H. Turner : Ninth note on the astrographic mag- 

 nitude scales : the Toulouse and Cape magnitudes, 

 with further remarks on the obscured patch in the 

 sky, considered as a spiral. The data for the southern 

 hemisphere were unfortunately very incomplete, as 

 there is a gap in the observations between — 1° and 

 — 31''. — J. H. Jeans : The theory of star-streaming and 

 the structure of the universe. Various hypotheses were 

 considered, and it was concluded there is no hope of 

 unravelling the mechanism of the universe by assum- 

 ing that it is in a steady state, or of using the observed 

 phenomena of star-streaming for exploring its struc- 

 ture. — J. H. Reynolds : Photographs of Jupiter, taken 

 in November with the 28-in. reflector. — G. E. Hale : 

 Spectroheliographs of a remarkable disturbed region 

 of the sun, August 7, taken at the Mount Wilson 

 Solar Observatory, California.— W. H. Wright : Series 

 of photographs of the spectra of nebulae taken at the 

 Lick Observatory. It was hoped that they would 

 assist in a proper classification of nebulae by their 

 bright-line spectrum. The nuclei of most nebulae stood 

 high on the temperature scale, and red stars are not 

 associated with nebulae. An important circumstance 

 was the apjDearance in the spectra of lines of carbon 

 and nitrogen.— H. C. Plummer : The distribution of 

 stars in globular clusters ; and on the motions and 

 distances of the bright stars of type F. In the latter 

 investigation the author was greatly assisted by a table 

 of stellar motions in equatorial co-ordinates, and other 

 data, for stars of type F, by Mr. O. R. Walkey. 



Cambridge. 

 Philosophical Society, November 22.— Prof. Newall, 

 president, in the chair. — Prof. Hughes : Notes on 

 oysters, recent and fossil. The author exhibited and 

 described a large collection of recent and fossil oysters, 

 pointing out how the modification of shape to suit 

 changing conditions, as observed in recent specimens, 

 suggested explanations of the evolution of species, in 

 accordance with environment, among similar fossil 

 forms. — Dr. Marr : Fossil zones and geological time. 

 An attempt is made to estimate the time required for 

 the accumulation of the fossiliferous rocks by taking 

 the case of the chalk, comparing its rate of accumu- 

 lation with that of the modern globigerinous ooze, and 

 then calculating the number of fossil-zones in the 

 chalk and in the whole of the fossiliferous strata. 

 The result obtained suggests a minimum period of not 

 fewer than 21,000,000 years for the formation of the 

 fossiliferous strata. The controlling factors are too 

 uncertain to permit much stress to be laid on this 

 estimate, which is probably much too low, but accord- 

 ing to it the evolution of organisms from the begin- 

 ning of Cambrian times onwards need not have occu- 

 pied a period of time greater than that which on 



NO. 2407, VOL. 96] 



various grounds is granted to geologists by followers 

 of other sciences. The method may be applied with 

 nearer approximation to accuracy, in estimating the 

 relative importance of different groups of strata ; thus 

 the number of zones in Palaeozoic and Mesozoic rocks 

 respectively indicates that the period during which the 

 former were being laid down was not necessarily much 

 longer than that required for the accumulation of the 

 latter. — H. B. Fantham and Miss Annie Porter : In- 

 duced herpetomoniasis in birds. All the great classes 

 of European vertebrates, except birds, have been in- 

 fected by the authors previously with flagellates found 

 in various insects. Results are now given of some 

 experiments in • which birds have been similarly in- 

 fected. Herpetomoniasis can be induced in birds, for 

 example, canaries {Serinus canarius), sparrows {Passer 

 domesticus), and martins {Chelidon urbica) by feeding 

 them on insects containing herpetomonads, or on food 

 contaminated with insect faeces containing herpeto- 

 rnonads. Herpetomonas culicis from the gnat, Culex 

 pipiens, and H. jaculum from Nepa cinerea, have 

 fatally infected birds when fed to them. Both flagel- 

 late and non-flagellate herpetomonads have been found 

 in the internal organs of the infected hosts. The 

 cycle of the flagellates in the avian hosts resembled 

 that in the insects. Members of all classes of verte- 

 brates may be capable of acting as reservoirs of herpe- 

 tomoniasis, and the virus may exist in a very atten- 

 uated condition and so be difficult of detection. — 

 H. B. Fantham and Miss Annie Porter : Notes on cer- 

 tain Protozoa which may be found in cases of dysen- 

 tery from the Mediterranean war zone. The authors 

 dealt briefly with the morphology and life-histories of 

 Entamoeba histolytica, E. coli. Trichomonas hominis, 

 Chilomastix (Tetramittis) mesnili, Giardia (Lamblia) 

 intestinalis and Balantidium coli. The pathogenic 

 actions of these parasites were discussed. Various 

 preventive measures, the occurrence of carriers and of 

 reservoirs were indicated. The modes of treatment 

 successfully used by recent workers were mentioned. — 

 Dr. Arber : A little-known concealed coalfield in Ox- 

 fordshire. The results of the Burford and Batsford 

 borings appear to show that, in this concealed coalfield, 

 the Coal Measures are red-grey productives, probably 

 belonging to the Transition Coal Measures. These 

 beds overlie Silurian rocks. The measures appear to 

 be related to those of the Newent and Wyre Forest 

 Coalfields, both lithologically and as regards horizon. 



Paris. 

 Academy of Sciences, November 29. — M. Ed. Perrier 

 in the chair. — The President announced the death of 

 Charles Rend Zeiller.— Maurice Hamy : The determina- 

 tion of radial velocities with the prism objective. In 

 a preceding communication a method was sketched 

 for the determination of the radial velocities of stars, 

 making use of a prism objective. Detailed calculations 

 are now given. — H. Douvill^ : The Orbitoids : their 

 development and embryonic phase. Their evolution 

 during the Cretaceous period. — M. de Segnier : The 

 equations of certain linear groups in a Galois field. — 

 M. Pigeaud : The elastic equilibrium of an indefinite 

 plate of uniform thickness, compressed by two equal 

 and opposite forces, uniformly distributed along two 

 parallel right lines situated in a plane normal to the 

 bases.— CEchsner de Coninck and Gerard : The atomic 

 weight of cadmium. Details of the method employed 

 for the purification of the commercial cadmium are 

 given. The experimental ratio determined was cad- 

 mium oxide from cadmium carbonate, and the mean 

 of five determinations was 112-32, as against the 

 atomic weight adopted by the International Com- 

 mission, 112-40. — O. Bailly : The mechanism of the 

 action of the tribasic sodium phosphate on the a-mono- 



