366 



NATURE 



[December 4, 1919 



from it as the number of electrons increases, more 

 energy going forward in the direction of the incident 

 ravs than backward. This asymmetry is retained, 

 though to a less extent, by an irregular assemblage 

 of similar electron rings with their axes distributed 

 uniformly in space. An expression is obtained for the 

 scattering coefficient, or mean total energy scattered 

 per ring per unit intensity of the incident radiation, 

 in a finite form, depending upon the number of elec- 

 trons in the ring and on the ratio which its radius 

 bears to the wave-length of the incident radiation. 



Physical Society, November 14. — Prof. C. H. Lees, 

 president, in the chair.— S. Butterworth : The self- 

 inductance of single-layer flat coils. Two for- 

 mulas are established for the computation of the self- 

 inductance of single-layer flat coils, one for the case 

 when the inner and outer radii are not very different, 

 and the other for the case of small inner radius. 

 The two formulae are shown to be consistent and 

 capable of including all possible cases. — Dr. N. W. 

 McLachlan : .\n e.xperimental method of determining 

 . the primary current at break in a magneto. A method 

 of obtaining experimentally the current at break in 

 a magneto is described. .\ condenser is connected 

 across the secondary winding to reduce the voltage 

 below that required to cause sparking at the safety 

 gap. The peak voltage due solely to interruption of 

 the current at any speed is found. The interrupted 

 direct current necessary to give the same peak voltage 

 is also found by using a calibrating circuit. The 

 magnitude of this current is equal to that broken in 

 the magneto. The influence of the secondary con- 

 denser on the primary current at high speeds is dis- 

 cussed. — F. W. Newman : K new form of Wehnelt 

 interrupter. 



Royal Meteorological Society, November 19. — Sir 

 Napier Shaw, president, in the chair. — Lieut. C.W. B. 

 Normand : Effect of high temperature, humidity, and 

 wind on the human body. The climatic conditions 

 under which a wet bulb, restricted to a certain maxi- 

 mum rate of evaporation and having an initial tem- 

 perature of 365° C, will neither gain nor lose heat 

 are derived from kata-thermometer and wet-bulb 

 formulae. The application of these results to the 

 human body is then considered, and, on the assump- 

 tion that conditions resulting in a rise of body tem- 

 perature above 365° C. must be fatal, the upper limits 

 to liveable climatic conditions are deduced. The 

 scorching, and sometimes deadly, simoom of tropical 

 deserts is considered to be a case of the onset of a 

 high wind without necessarily a change of tempera- 

 ture or humidity, converting liveable into unliveabU- 

 conditions. The suggestion is also made that an 

 essential feature of heat-strokes may be that a portion 

 of the body has been exposed for a time to air condi- 

 tions which are above the limit for existence. Th^ 

 wot kata-thermometer and wet-bulb formula; were 

 found to furnish quite discordant results regarding the 

 behaviour of a wet surface under var>ing wind velo- 

 cities, and it is suggested that this discrepancy is due 

 to a less efficient wetting of the kata-thermometer 

 bulb and to a consequently restricted rate of evapora- 

 tion from it. — Capt. A. j. Bamford : Some observa- 

 tions of the upper air over Palestine. This paper gives 

 a brief summary of some upper-air observations made 

 in Palestine during the last two years. Tables and 

 graphs are given showing the monthly averages of the 

 horizontal movements at different altitudes over three 

 stations, at one of which (near Ramleh) observations 

 were kept up continuously for a year. The ?econd 

 Dart of the paper deals with vertical velocities, and 

 includes frequency curves, showing for each of the 

 lavers 0-2000 ft., 2000-4000 ft., and 4000-6000 ft. the 

 number of times in each month that the observed 



NO. 2614, VOL. 104] 



velocities differed from the theoretical ones bv no' 

 more than 10, 20, 30, or 40 per cent., etc. The lowest 

 layer is appreciably the most varied, and in it differ- 

 ences of 50 per cent, are not unusual, although the 

 average velocity differs very slightK from theory. In 

 the other layers there is a distinct increase in the 

 compactness of the frequency curves, while the 

 average velocity changes from slightly abos'e to 

 slightly below the theoretical value. — E. G. Bilham : 

 Barometric pressure and underground water-level. 

 The results recently obtained from a studv of an 

 experimental well with autographic registration at 

 Kew Observatory, Richmond, Surrey, are compared 

 with some earlier records obtained by Dr. Isaac 

 Roberts at .Maghull, near Liverpool, and by Prof. K. 

 Honda in the neighbourhood of Tokyo, in japan. .As 

 at Kew, the sensitiveness of thp water surface at 

 jMaghull to pressure changes varies considerably, high 

 sensitiveness being associated with saturation of the 

 soil by previous heavy rainfall. In Japan it was found 

 that in surface wells the water-level was not affected 

 by pressure changes, sensitiveness being exhibited bv 

 deep artesian wells only. Prof. Honda has pointed 

 out that by determining the sensitiveness of a well 

 to barometric pressure the extent to which pressure 

 changes affect strata at a given depth below the sur- 

 face can be deduced. Data for Japan and the Britisri 

 Isles obtained m this way show maiked points of 

 difference. 



Cambridge. 

 Philosophical Society, November 10.— Mr. C. T. R. 

 Wilson, president, in the chaii . — Dr. Hartridge : 

 Colorimeter design. — J. T. Saunders : A note on 

 hydrogen-ion concentration and photosynthesis. Spiro- 

 gyra and elodea during photosynthesis cause the sur- 

 rounding water to become markedly alkaline; .Acids 

 are very rapidly absorbed. — J. Gray : (i) The effects 

 of some ions on spermatozoa. \ suspension of 

 Echinus spermatozoa in sea-water behaves in an elec- 

 tric field or in the presence of hydrogen ions or tri- 

 valent ions in the same way as an emulsion cf 

 albumen in alkaline solution. (2) The effects of ions 

 on ciliarv movement (gills of Mytilus edulis). By far 

 the most potent ions in sea-water which affect ciliarv 

 movement are hydrogen ions and hydroxyl ions.- - 

 C. Warburton : Note on the solitary wasp, Crabro 

 cephalotes. A small colony of C. cephalotes took pos- 

 session in .August, 1919, of a log in the author's 

 garden, and afforded an opportunity of studying their 

 habits with some accuracy. Observations were made 

 on the time occupied in capturing and bringing home 

 their prev and in packing them in the burrows. — 

 Miss M. D. Haviland : Preliminary note on the lifi'- 

 history of a Proctotrypid (Lygoccrus sp.) hyper- 

 parasite of .Aphidius. Lygocerus Cameroni. Kieff 

 (Proctotrypidae), is a hyperparasite of certain 

 Braconid parasites of plant-lice, and not a parasite 

 of the aphides themselves, as has hitherto been 

 assumed.— H. J. Snell and W. H. Tarns : The natural 

 history of Rodrigues, with exhibits. The paper gives 

 a brief account of the island of Rodrigues as it at 

 present exi.sts. Since it was first discovered it appears 

 to have been completely swept by fire, .save only for 

 peculiar deep pits in the elevated coral rock which in 

 places overlies the volcanic. Here a certain number 

 of the indigenous plants still survive, but probably the 

 species in the flora are only half as numerous as when 

 the island was first discovered ; great damage has 

 also been done bv pigs and goats. The fauna 

 previously described was almost in its size that of a 

 coral island, but the present collections reveal much 

 larger numbers of species and more variety, indicating 

 probably a greater age for the island ; the fauna also 

 shows a close parallel to that of Mauritius and other 

 volcanic islands in its adaotabilitv to island conditions. 



