462 



NATURE 



[April 8, 1922 



of the length standards of the N.P.L. and the value in 

 absolute millihenries has been calculated. Compari- 

 sons with the similar laboratory standard at a fre- 

 quency of ten cycles per second showed that the ratio 

 of the calculated values of the two standards was in 

 agreement with the ratio of the experimentally com- 

 pared values to an accuracy of 5 in 10*. — P. E. Shaw 

 and N. Davy : The effect of temperature on gravita- 

 tive attraction. Results with a torsion balance of the 

 Boys-Cavendish type indicated a temperature effect 

 of gravitation of about i x 10-* per 1° C. With 

 similar apparatus modified to eliminate small mechan- 

 ical movements caused possibly by the raising of the 

 large gravitative masses to a high temperature, the 

 effect was shown to be due to such movements 

 reversible with temperature. The temperature effect, 

 if any, must be less than 2 x io~® per 1° C. The mean 

 effect observed is a very small diminution in attraction 

 as temperature rises. 



Zoological Society, March 7. — Sir Sidney F. Harmer, 

 vice-president, in the chair. — N. S. Lucas : Report 

 on the deaths which occurred in the Society's Gardens 

 during 1921. — R. Broom : On the temporal arches of 

 the ReptiUa.— F. V. Urich, H. Scott, and J. Waterston : 

 The bat-parasite Cyclopodia greeffi, and a new species 

 of hymenopterous (Chalcid) parasite bred from it. — 

 S. V. Montgomery : Direct development in a Dromiid 

 Crab. — F. Balfour- Brown : The Hfe-history of the 

 water-beetle, Pelobius tardus, Herbst. 



March 21. — Dr. A. Smith Woodward, vice-president, 

 in the chair. — P. Chalmers Mitchell : Monkeys and the 

 fear of snakes. — G. Blaine : Notes on the zebras and 

 some antelopes of Angola. — R. I. Pocock : On the 

 external characters of some Histricomorph Rodents.— 

 H. R. Hogg : Some spiders from South Annam. 



Physical Society, March 10. — Dr. Russell, president, 

 in the chair. — R. L. Smith-Rose : On the electro- 

 magnetic screening of a triode oscillator. The most 

 complete method of screening a valve set is to enclose 

 it in a hermetically sealed box made of metal of 

 suitable thickness for the frequency used. The 

 smallest crack allows a detectable amount of the 

 high-frequency, energy to escape. Iron is far more 

 effective than copper of the same thickness in pre- 

 venting direct penetra-t;jon of radio-frequency mag- 

 netic fields through the metal. — H. P. Waran : A 

 new form of high vacuum automatic mercury pump. 

 The pump, based on a modified Sprengel action, 

 works automatically, the mercury being removed 

 from the lower to the upper reservoir mixed with a 

 current of dry air which is sucked through a side 

 tube by a filter pump. An intermediate reservoir 

 in the middle of the fall tube, kept automatically 

 exhausted by the Sprengel action in the lower fall, 

 allows the upper half to exert a positive exhaustion 

 for every pellet of mercury falHng down. The 

 absence of compression in the first fall makes it 

 possible to use the maximum bore for the fall tube. 

 Less than a pound of mercury is required to operate 

 the pump. — W. N. Bond : Viscosity determination 

 by means of orifices and short tubes. General ex- 

 pressions for the end-corrections obtained by the 

 method of dimensions are employed in plotting the 

 results of experiments on the flow of mixtures of 

 glycerine and water through pairs of tubes of 

 equal diameter, but of different lengths. The 

 conditions that the flow at the ends may be purely 

 viscous and equations for determining the viscosity 

 are given. 



Royal Meteorological Society, March 15. — Dr. C. 

 Chree, president, in the chair. — E. M. Wedderburn : 

 Seiches ; and the effect of wind and atmospheric 



NO. 2736, VOL. 109] 



pressure on inland lakes. " Seiche " is the name 

 originally given in Switzerland to quasi-tidal move- 

 ments of tile level of inland lakes. In 1905 the late 

 Prof. Chrystal investigated the seiches in Loch Earn 

 for the Scottish Lake Survey, and found that micro- 

 bari-c disturbances were the most frequent cause of 

 seiches. Other possible causes are heavy rainfall 

 over part of the lake, rapid flooding and wind squalls. 

 Earth tremors rarely cause considerable movements. 

 The Scottish Lake Survey also discovered internal 

 seiches of large ampUtude. During autumn there 

 is at the surface a layer in which there is little varia- 

 tion of temperature with depth. Below this is a 

 narrow layer, the discontinuity layer, in which the 

 fall of temperature is rapid, while below this again is the 

 bottom water of the lake in which temperature 

 variations are small. The effect of wind blowing 

 along a lake is to accumulate the warm surface water at 

 the lee end, so that the discontinuity layer is displaced 

 from its normal horizontal position. When the wind 

 moderates a standing oscillation commences at the 

 discontinuity layer. The period of oscillation depends 

 on the difference of density between these layers ; 

 the amplitude may be several feet, without causing 

 measurable disturbance of the level of the free 

 surface. 



Cambridge. 

 British Mycological Society, March 18. — Mr. F. T. 

 Brooks, president, in the chair. — Mrs. M. N. Kidd : 

 Diseases of apples in storage. Moulds attacking 

 apples in storage show a definite sequence and cause 

 a different amount of loss. Physiological diseases 

 are of considerable importance. Scald and probably 

 others can be completely controlled by wrapping 

 the fruit in specially prepared paper. — J. Line : 

 Parasitism of Nectria cinnabarina. This fungus 

 is associated with a characteristic wilting of appar- 

 ently healthy branches, the wood of which is brown 

 to green and occluded with fungal hyphae. Pure 

 cultures of the fungus were incapable of estabUshing 

 the hyphse in living wood or cortex but succeeded 

 on artificially killed plants, and finally were able to 

 pass into healthy wood. — -K. C. Mehta : Observations 

 on the occurrence of wheat rusts near Cambridge. 

 Puccinia graminis does not overwinter by uredospores 

 nor by mycelium inside the host plant ; its recur- 

 rence is explained only through fresh infection by 

 aecidiospores produced on Barberry. In P. triticina 

 and P. glumarum viable uredospores can be found 

 during the greater part of winter, and there is con- 

 clusive experimental evidence that these rusts can 

 overwinter by means of mycelium inside the host 

 plants.— F. T. Brooks and C. G. Hansford : Mould 

 growths on cold store meat. Meat from the southern 

 hemisphere showing mould growths was investigated. 

 Some of these fungi, particularly Cladosporium 

 herharum ("black spot"), can develop at —6° C. ; 

 other moulds grow readily at temperatures about 

 freezing-point. At several degrees above this, 

 bacterial growth is so active as to . suppress the 

 moulds. The fungi are only superficial and, unless 

 accompanied by putrefactive bacteria, do not render 

 the meat unfit for food. 



Dublin. 

 Royal Dublin Society, March 28. — Dr. J. A. Scott 

 in the chair. — J. J. Nolan and J. Enright : Experi- 

 ments on the electrification produced by breaking 

 up water, with special application to Simpson's 

 theory of the electricity of thunderstorms. Different 

 samples of water were tested. The purer water 

 gives higher charges, the difference being very great 

 for small degrees of breaking-up. With more com- 

 plete pulverisation the charge produced tends to be 



