July 14, 192 1] 



NATURE 



639 



with different gases and with different adsorptive sub- 

 stances to ascertain the volume of gas adsorbed at 

 pressures up to loo atmospheres. The tests show that 

 it is possible to increase the gas capacity of a cylin- 

 der, holding the gas under compression, if the 

 cylinder be completely filled with coconut charcoal 

 before the gas is pumped in. The reason for certain 

 sudden outbursts of fire-damp in coal mines is stated 

 to be due to the adsorption of that gas under pressure 

 by the coal. In some cases millions of cubic feet of 

 fire-damp Bave been suddenly discharged in mines 

 when t"he equilibrium was disturbed. — Miss Elizabeth 

 Gilchrist : The utilisation of solid caustic soda and 

 the absorption of carbon dioxide. The experiments 

 aimed at ascertaining the optimum condition for the 

 absorption of carbon dioxide by solid caustic soda 

 granules, especially with the object of improving that 

 action in mine rescue apparatus. The absorption 

 diminishes at temperatures approaching o° C. and 

 at temperatures exceeding ioo° C. The behaviour of 

 a caustic granule at or near the optimum condition is 

 described, it being shown how the granule swells 

 gradually, eventually becoming a shell of carbonate 

 hollow within. — Miss Augusta Lament : The de- 

 velopment of the feathers of the duck during the 

 incubation period. The external appearance and the 

 internal structure of the feather-papillae are figured 

 and described, and special stress is laid on the dis- 

 tinction between pennaceous and plumaceous feathers 

 during their earliest stages. The work is preliminary 

 to further researches. — A. G. Ramage : Note on the 

 conditions for mirage on the Queensferry Road. The 

 surface of the road was remade in the spring of 19 ig 

 with road metal and liberal supplies of bitumen, and 

 small pieces of quartz scattered oni the top of the 

 bitumen, the whole being rolled by a steam-roller. 

 After this had been done no signs of the mirage, so 

 common on this road the previous summer, made 

 their appearance until August,, and then but faintly. 

 During the summers of 1920 and 192 1, on bright 

 days, mirage was again much in evidence, showing 

 that a newly made road is not conducive to the appear- 

 ance of the mirage phenomenon. 



Dublin. 



Royal Dublin Society, June 28.— Dr. F. E. Hackett 

 in the chair. — Prof. T. Johnson and Jane G. Gilmore : 

 The occurrence of a Sequoia at Washing Bay, Co. 

 T\-rone. The conifer was found in the core of the 

 coal-bore, especially in the zone between 890-930 ft. It 

 is represented by wood, by shoots showing dimorphic 

 foliage, by cones and pollen-grains. The authors find 

 it to agree in all respects with 5. Couttsiae, Heer, 

 from the upper Oligocene of Bovev Tracey, Devon- 

 shire. They have also examined Baily's type material 

 of 5. du Noyeri, and refer it to S. Couttsiae as a 

 possible variety. They describe one specimen showing 

 the two types of foliage on the same shoot. The 

 paper also contains an account of the distribution and 

 characters of the stomata in Sequoias, recent and 

 fossil. — P. A. Murphy : The sources of infection of 

 potato tubers with the blight fungus, Phytophthora 

 infestans. The results of field experiments in Canada 

 and Ireland on the decay caused by the blight fungus 

 in potato tubers, with particular reference to the rot 

 which sets in after dieHncr, are detailed. When 

 blight rot is found in quantity in the pits in winter 

 it does not owe its origin to the spreading of the 

 disease from a few initially infected tubers. Many 

 tubers not visibly diseased carry the infection with 

 them to the pits.' The source of infection has been 

 traced to contact of the tubers at digging time with 



NO. 2698, VOL. 107] 



blighted, but partially living, foliage, and with con- 

 taminated surface soil. The conidia live in the soil 

 for at least two weeks after the death of the tops, 

 and such soil may be a dangerous source of infection. 



Paris. 



Academy of Sciences,^ June 20. — M. Georges Lemoine 

 in the chair. — H. Andoyer : The direct demonstration 

 of a theorem of Tisserand relating to the development 

 of the perturbation function. — E. Houg : The tec- 

 tonic of the coast region between Saint-Cyr and 

 Hyeres. — C. Richet, Mile. Eudonie Bachrach, and H. 

 Cardot : The alternations between tolerance and 

 anaphylaxy. Studies on the lactic ferment. Succes- 

 sive generations of the bacillus show at first a decrease 

 in activity by small proportions of mercuric chloride 

 in the culture media, then get accustomed and in- 

 crease in activity (measured by the lactic acid formed), 

 but lose this tolerance later, become sensitive, and 

 are killed. With smaller doses of the poison there is- 

 at first an acceleration, then an anaphylactic phase, 

 and finally death of the organism.- — C. Deperet and 

 M. Solign'ac : The Sahalian of northern Tunis. — M. 

 de Sparre : The yield of turbines working with a 

 variable head,— W. Kilian and F. Blanchet : The 

 presence of a sub-alluvial sheet of thermal or mineralised 

 water in the bed of the Durance, at Serre-Pongon. 

 These hot springs were discovered in the course of 

 work carried out in connection with the construction 

 of a hydro-electric power station. The water was 

 saline, temperature 47° to 49° C. — B. Gambier : The 

 deformation of surfaces and the Laplace equation. — 

 L. Dunoyer : The complete chr on ©photographic deter- 

 mination of trajectories. The method is based on the 

 simultaneous photography from two determined posi- 

 j tions of the path of a luminous projectile. — A. 

 I Sanfourche : The absorption of the oxides of nitrogerj 

 j by sulphuric and nitric acids. — L... Guillet and M. 

 Ballay : Critical points due to hardening caused by 

 wire-drawing. The hardened wire has a part an- 

 nealed, and the electrical resistances of the annealed 

 and unannealed portions are compared at various 

 temperatures ; the results are recorded on a differen- 

 tial curve. This electrical method is superior to the 

 dilatometric and other methods in use. — A. C. Vour- 

 nazos : A new magnesian hydraulic cement. A 

 description of the preparation and properties of some- 

 cements produced from magnesia (magnesite calcined 

 at a low temperature) and powdered pumice or silica. 

 — M. Baille-Barrelle : Contribution to the study of 

 the coking of Saar coals. — A. Mailhe : The catalytic 

 decomposition of the polyhalogen derivatives of the- 

 paraffins. A study of the reduction of tetrachloro- 

 acetylene, tetrabromoacetylene, chlorodibromopro- 

 pane, dichlorodibromoacetylene, and trichloro- 

 dibromoacetylene by hydrogen in presence of 

 reduced nickel and barium chloride as catalysts. 

 The product is always a halogen-substituted 

 ethylene. When there are different halogens the- 

 bromine is first removed by the hydrogen. — J. B. 

 Senderens and J. Aboulenc : The catalytic decomposition 

 of the bromoacetic acids and of mixtures of bromine 

 and acetic acid. — J. Savornin : Observations on the- 

 Palaeozoic of Rabat, Morocco. — P, Bonnet : Meso- 

 cretaceous volcanic eruptions and their relations with 

 the distribution of the facies in the Caucasian geo- 

 synclinals. — J, Cvijid : River platforms and erosion 

 steps.— Mile. Y. Boisse de Black : The " frane " of 

 the Cfere Valley. — A. Treuthardt : Some new measure- 

 ments of the density of the air at Geneva. Some 

 results of measurements carried out in 19 17. The 

 deviations observed are larger than the experimentat 

 error, and the values below the average (1-29269) were 

 obtained when the barometric pressure was above the 



