690 



NATURE 



[Ff.bruar\ 20, 19 1 3 



Achromatism for all colours is preserved completelv 

 by making all the lenses of the same glass. The firs't 

 of these lenses is a meniscus silvered at the back, 

 and besides adjusting the ailiromatism of the other 

 Uvo, serves to reverse the direction of the ray. The 

 other two form a pair of nearly equal but opposite 

 focal lengths and intercept the outcoming beam. By 

 a proper distribution of curvatures between their faces 

 they introduce correcting aberrations. The resulting 

 field is completely corrected for colour, spherical aber- 

 ration, coma, and curvature of the field. — Prof H E 

 Armstrong and Dr. J. V. Eyre: Studies of the pro- 

 cesses operative in solutions. XXV., The influence 

 of non-electrolytes on solubilitv. The nature of the 

 processes of dissolution and' precipitation. — E. E. 

 VValker : Studies of the processes operative in solu- 

 tions. XXVI., The disturbance of the equilibrium in 

 solutions of fructose by salts and by non-electrolytes. 

 —J. Chadwick and A. S. Russell : The excitation of 

 7 rays by the a rays of ionium and radiothorism. The 

 work on the excitation of 7 rays by a rays, shown 

 first by Chadwick in the case of the a rays of radium 

 C", has been extended to ionium. K preparation of 

 innium and thoriimi equal in a-ray activity to 3 mgr. 

 of radium, after purification from all radio-active 

 bodies which emit fi and 7 rays, was found to emit 

 a small but easily detectable amount of 7 radiation. 

 This radiation is shown to be excited by the a rays, 

 either in the ionium itself, or in the thorium w'ith 

 which_ it is mixed. It s a mixture of three types of 

 radiation differing widely in penetrating power. — 

 Prof. W. E. Dalby : Load-extension diagrams taken 

 with the optical load-extension indicator. In this 

 [japer further experiments with the indicator are 

 described. The optical load-extension indicator itself 

 was fully described and illustrated in a paper read on 

 March 7, IQ12. Load-extension diagrams obtained 

 from phosphor-bronze, gun-metal, and brass are 

 shown, together with photomicrographs taken from 

 the specimens tested. The chemical analyses of the 

 nietals are given in each case. The effect of anneal- 

 ing brass rod is brought out by comparing the load- 

 extension diagrams of an annealed and an unannealed 

 specimen and by making a similar comparison of the 

 corresponding photomicrographs of the structure of 

 the material. The physical effect of annealing is 

 lo produce a state in which the load-extension curve 

 approaches the shape given by copper, and bears 

 little resemblance to the curve obtained from the same 

 material in an unannealed state. 



Zoological Society, February 4.— Sir John Rose Brad- 

 ford, K.C.M.G., F.R.S., vice-president, in the chair. 

 —Dr. F. E. Beddard : The anatomy and systematic 

 arrangement of the Cestoidca. The" paper dealt with 

 a number of new species of Ichthyotaenia and Ophido- 

 tjEnia obtained from the gut of serpents that had died 

 in the gardens.— H. G. Plimmer : Report on the deaths 

 which occurred in the societv's gardens during the 

 past year, together with a list of the blood parasites 

 found during the same period. An examination had 

 been made of the blood of every animal that had 

 died, with the result that parasites had been discovered 

 in 140 cases, and in eighty of these for the first time. 

 — H. L. Hawkins : The anterior ambulacrum of 

 Echinocarditim cordaium and the origin of compound 

 plates in the Echinoidea. A new method was de- 

 scribed of exposing sutures in recent Echinoids suit- 

 able for photographic purposes, the process combining 

 staining with etching, and the description of the com- 

 plex plating of amiDulacrum III. in E. cordatuni. 

 The origin of ambulacrum "plate-crushing," founded 

 on a brief survey of the phenomenon in all groups 

 of Echinoids, was discussed. Mechanical growth- 

 pressure was regarded as the cause, with the growth 



NO. 2260, VOL. go] 



of tubercles (Lambert's hypothesis) as a secondary 

 and merely modifying agent. — G. P. Farran : Plankton, 

 from Christmas Island, Indian Ocean. IL, Copepoda 

 of the genera Oithona and Paroithona. This collec- 

 tion, made in igo8 by Sir John Murray and Dr. C VV. 

 Andrews, contained eleven species of Oithona and one 

 of Paroithona, or rather more than half the known 

 species, the total number of known species of Oithona 

 being eighteen and of Paroithona two. This indicated 

 the great richness in species of collections made in 

 tropical waters. Seven of the species of Oithona and 

 the one Paroithona appeared to be new to science. 



Linnean Society, February 6.— Prof. E. B. Poulton, 

 F.R.S., president, in the chair. — A. W. Sutton : Re- 

 sults of crosses between a wild pea from Palestine, 

 presumably Pisiini hiimilc, Boiss and Noe, and culti- 

 vated forms. — Miss Bancroft : The structure of 

 Rhexnxylon ajricanum. A fossil stem described by 

 Dr. A. W. Rogers as probably coming from the 

 Karroo rocks of Cape Colony, indicates atlinities with 

 the Medullosew of later Palaeozoic age.: — D.-. R. 

 Verity : Revision of the Linnean types of Palaearclic 

 Rhopalocra. 



Mathematical Society, February 13. — Prof. \. E. H. 

 Love, president, in the chair. — T. C. Lewis : Figures 

 in )i-dimensional space analogous to orthocentric tetra- 

 hedra. — J. E. I.ittlewood : A property of the f-function. 

 — G. H. Hardy : The summability of a Fourier's series. 

 — G. H. Hardy and J. E. Littlewood : Trigonometrical 

 series which converge nowhere or almost nowhere. — 

 H. Bohr : A theorem concerning power series. — P. J. 

 Heawood : .\ graphical demonstration of the funda- 

 mental properties of quadratic residues. — J. B. Holt : 

 The irreducibility of Legendre's polynomials (third 

 paper). — W. H. Young ; The mode of oscillation of a 

 Fourier series and its allied series. — H. T. H. Piaggio •. 

 Some non-primarv perpetuant syzygies of the second 

 kind. 



Manchf.ster. 



Literary and Philosophical Society, February 4. — Prof. 

 F. E. Weiss, president, in the chair. — D. Thoday : A 

 capillary eudiometric apparatus for analysing small 

 volumes of air. Results of experiments relating to 

 the exchange of gases between plants and the atmo- 

 sphere.— V/. B. Brierley : The structure and life- 

 history of Sphacria Icmaueae. The author traced the 

 origin and development of the vegetative and repro- 

 ductive organs of Spliaeria lemancae, a fungus in- 

 habiting se.xual filaments of Lemanea. The relations 

 obtaining between the host and parasite were eluci- 

 dated, and the morphological structure and cytology 

 of the fungus shown to be in general agreement with 

 previous knowledge of Pyrenomycetous fungi. The 

 accepted systematic position of Sphacria lemancae 

 was questioned. 



Paris. 



Academy of Sciences, February 10. — M. F. Guyon in 

 the chair. — Pierre Duhem : Two fundamental inequali- 

 ties of thermodynamics. — Paul Sabatier and i\I. Murat : 

 The direct addition of hydrogen to the phenylacetic 

 esters : the preparation of cyc/olie.xylacetic acid. This 

 reaction requires a large excess of hydrogen in pre- 

 sence of a very active nickel, maintained at 180° C. 

 The yield is quantitative, no loss occurring through 

 secondary reactions. The properties of cyc/ohe.xyl- 

 acetic acid and of five of its esters are described. — 

 Charles Deperet : Observations on the Pliocene and 

 Quaternary geological history of the gulf and isthmus 

 of Corinth. — Hugo de Vries was elected a correspon- 

 dant of the academy in the section of botany, 

 in the place of M. Schwendener, elected 

 foreign associate. — Mile. S. Tillinger : The determina- 

 tion of the growth of functions defined by a Taylor's 



