July 2t, 1923] 



NA TURE 



119 



per min. a sevenfold increase in the rate of evapora- 

 tion was obtained as compared with the rate of 

 evaporation on a water or steam bath. A new form 

 of laboratory" evaporator described consists of a 

 glass bulb, containing the liquid, mounted on fibre 

 bearings, and rotated by a small motor, while it is 

 heated directly by a bunsen burner. The rotation 

 prevents the liquid in contact with the glass bulb 

 from becoming super-heated, and, besides keeping 

 the liquid mixed, spreads it out in a thin film on the 

 upper surface of the bulb while a current of air or 

 indifferent gas can be blown through the bulb. It is 

 possible to obtain rates of evaporation up to twenty- 

 four times as great as that on the water bath. — 

 H. G. Becker and W. E. Abbott : A rapid gasometric 

 method of estimating dissolved oxygen and nitrogen 

 in water. The gas is expelled by dissolving an 

 electrolyte in the water, the displaced gas being 

 liberated in a partial vacuum, collected, and measured. 

 Caustic potash is the most satisfactory electrolyte. 

 The analytical results are comparable with those 

 obtained by the Winkler and boiling-out methods. 

 The advantages claimed are simplicity of apparatus, 

 rapidity, and smallness of the water sample required 

 for a determination. — W. R. G. Atkins and M. V. 

 Labour : The hydrogen ion concentration of the soil 

 and of natural waters in relation to the distribution 

 of snails. The hydrogen ion concentration of the 

 soil is a factor limiting the distribution of snails, 

 which are far more numerous between Ph7 and Ph8 

 than elsewhere. Of 27 species of snails found in the 

 districts studied, 4 species occurred at Ph5, 20 species 

 at Ph7, and 14 species at Ph8. Snails with hyaline 

 shells occur over a wide range, but those with 

 calcareous shells are limited to the more alkaline 

 soils. Granite and quartzite regions have few species, 

 basaltic districts have a more numerous fauna, and 

 limestone areas are rich both in variety of species 

 and number of individuals. The distribution of 

 some species within the British Isles is probably 

 explained by the " age and area " theory of Willis, 

 rather than by a limitation through unfavourable 

 ecological factors. Cochlicella barbara appears to 

 have a western, and Theba cantiana an eastern, origin. 



Paris. 



Academy of Sciences, June 25. — M. Albin Haller 

 in the chair. — Maurice Hamy : The determination 

 of small diameters by the interference method. — 

 P. A. Dangeard and Pierre Dangeard : Second note 

 on the vitality of leaves of Aucuba preserved in a 

 ^•acuum. The Aucuba leaf after being in a vacuum 

 for twelve months resembled, macroscopically and 

 microscopically, a freshly plucked leaf. It retained 

 its original green colour, and the vitality of its cells 

 was undiminished. — Morin MoUiard : The deter- 

 mining factor in the formation of conidia in Sierigmato- 

 cystis nigra. The formation of conidia is determined 

 by a deficiency of phosphorus or other nutritive 

 element in the culture fluid, together with an excess 

 of potassium. — V. Grignard and R. Escourrou : The 

 methylheptenols : their ketonic decomposition. — 

 F. H. van den Dungen : Calculation of the simple 

 poles of a meromorphic fimction. — Gino Fano : The 

 congruence of the nonnals to a quadric. — L. Decombe : 

 The analytical theory of irreversibility. Elementary 

 isokinetic transformations. — C. Gutton, S. K. Mitra, 

 and V. Ylostalfi : The high-frequency discharge in 

 rarefied gases. The frequency range in these experi- 

 ments varied between 50 and 2,140,000, and tubes 

 with internal and external electrodes were used, the 

 gas being dry air. The potential varied with the 

 frequency, and for tubes with internal electrodes 

 the difference of potential always increased with 



NO. 2803. VOL. 1 12] 



the frequency ; for tubes with external electrodes 

 the pressure of the gas affected the relation between 

 potential and frequency. — Jacques Errera : Colloidal 

 supports for obtaining the emission spectra of solu- 

 tions. The spark is passed between rods of gelatin 

 containing the salt under examination ; the method 

 has the advantage that fewer lines are introduced 

 into the spectra by the electrodes than when metal 

 or glass supports are used for the solutions. — M. 

 Duffieux : The mass of the particles which emit the 

 secondary spectrum of hydrogen. The experiments 

 described lead to the conclusion that all the lines 

 examined in the secondary hydrogen spectrum must 

 be attributed to the molecule of hydrogen. — Mile. 

 St. Maracineanu : Researches on the constant of 

 polonium. Published values for the period of 

 polonium vary between somewhat wide limits, 

 134-5 "to 143 days. The value 139-5 days is regarded 

 as the most probable. Deposition of radioactive 

 substances on glass is preferable to deposition on 

 metal plates in researches of this nature. — G. Dupont 

 and L. Desalbres : A curious case of separation of 

 optical isomerides by distillation and by crystallisa- 

 tion. A partial separation of active and inactive 

 pinene can be made by fractional distillation with 

 a very efficient column ; evidence of a similar separa- 

 tion has been obtained by fractional crystallisation 

 3-t - 75° C. — M. Geloso : Isotherms of the adsorption 

 of salts by manganese dioxide. Experimental results 

 of the adsorption of copper, nickel, and iron by 

 precipitated manganese dioxide : a simple expression 

 is deduced which accurately expresses the experi- 

 mental data. — Paul Pascal : The magnetic properties 

 of cyanic and cyanuric compounds. From a study 

 of the magnetic susceptibility of compounds contain- 

 ing the groups (CNO) and (C3N3O3) and assuming 

 the law of additivity, conclusions are drawn con- 

 cerning the constitution of these compounds . Cyanuric 

 acid is regarded as possessing a structure similar to 

 the benzene nucleus, but isocyanurates and cyamelide 

 differ in structure, although containing a six-atom 

 ring. — Andre Charriou : The reciprocal displacement 

 of substances carried down by precipitates. Chromic 

 acid is carried down by a precipitate of aluminium 

 hydroxide, and this cannot be washed out with water 

 or with solutions of salts of monobasic acids ; the 

 chromic acid, however, can be removed completely 

 by washing with solutions of salts of dibasic or 

 tribasic acids (sulphate, oxalate, phosphate). — Henry 

 E. Armstrong : The origin of osmotic effects. Hydrono- 

 dynamic transformations in aqueous solutions. Dis- 

 carding the Arrhenius theory as irrational and in 

 disagreement with the facts, a resume of the hydrone 

 theory is given, and this is regarded as explaining 

 all the properties of aqueous solutions. — Alfred 

 Gillet and Femand Giot : It is common knowledge 

 that treatment of the fibre before dyeing with copper 

 salts in some cases increases the fastness to light. 

 It is shown experimentally that a preliminary treat- 

 ment of the fibre with cuprous salts exerts a strong 

 protective action against light for the dye 2B diamine 

 blue. — Max and Michel Polonovski : The constitution 

 of eserine. — Raymond Delaby : The action of fonnic 

 acid on ethylglycerol. Conversion into /3-ethylacrolein. 

 The decomposition of the crude mixture of formins 

 from ethylglycerol gives two unsaturated alcohols, 

 vinylethylcarbinol, CHg : CH . CH(OH) . C2H5, and 

 /3-ethylallyl alcohol. C^Hj . CH : CH . CHglOH), the 

 latter being new. — M. Pariselle : A new working 

 method for the preparation of camphene. In the 

 ordinary method of preparing pinene hydrochloride 

 a yield of 55-65 per cent, is obtained : the yield can 

 be raised to 75 per cent, by conducting the saturation 

 with hydrochloric acid in two steps, with a two days' 



