June 17, 1922] 



NATURE 



799 



I 



Societies and Academies. 



London. 

 Zoological Society, May 23. — Dr. A. Smith Wood- 

 ward, vice-president, in the chair. — E. G. Boulenger 

 and F. Martin Duncan : A cinematograph record of 

 the hfe-history of the Axolotl {Ambly stoma tigrinum). 

 — H. N. Hutchinson : A model reconstruction of 

 the marine reptile Peloneiistes philarchus, a Pliosaur 

 from the Oxford Clay. — Sir Sidney F. Harmer : 

 On Commerson's dolphin and other species of 

 Cephalorhynchus. — C. Forster Cooper : Miocene Pro- 

 boscidia from Baluchistan. — R. I. Pocock : On the 

 external characters of Scarturus and other jerboas 

 compared with those of Zapus and Pedetes. 



Cambridge. 

 Philosophical Society, May 15.— Mr. C. T. R. 

 Wilson, vice-president, in the chair. — E. H. Hankin : 

 An experimental investigation of soaring flight. If 

 the loading {i.e. the weight lifted per square foot of 

 wing area) of soaring animals is plotted against the 

 span, a regular curve is obtained. The greater the 

 span, the greater the loading. The flying-fish is a 

 striking exception ; the loading is more than eight 

 times as much as it would be for a bird of similar 

 size, and as the speed is at least equal to that of 

 birds under similar conditions, the wings of flying- 

 fishes are more than eight times as efficient as 

 those of birds. A model of a fin-ray ( x 10) was 

 made of wood and fixed, convex side forward, 

 in front of the radiator of a motor. A mano- 

 meter measured any pressure that might develop 

 on the rear face of the fin-ray. When the air at 

 the level of the fin-ray was " soarable," as shown 

 by the behaviour of dragon-flies, a pressure of 6-10 

 mm. of water was obtained at the rear of the fin-ray 

 when the motor was travelling at 30 m.p.h. Generally 

 the pressure was greater at midday than at sunset, 

 it was abolished by rain, and also if the fin-ray was 

 so loosely fixed that it was thrown into vibration 

 by the passage past it of the air. The shape of the 

 ray was found to be of Uttle importance — the only 

 thing necessary being that there should be a sheltered 

 area. Probably the whole wing of a bird might be 

 so disposed as to give a sheltered area. Increase 

 of the sheltered area also resulted in increase of 

 speed. Entering into a descending current causes 

 ' an increase of sheltered area, and the expected 

 increase of speed has been observed with gulls, 

 which indulge in true soaring flight [i.e. steep up- 

 ward ghdes with the long axis of the bird inclined 

 upward and pointed in the direction of travel) only 

 when the bird is in a descending current of air. 

 Inland soaring birds and dragon-flies show similar 

 effects. — F. P. White : The projective generation of 

 surfaces in space of four dimensions. — C. G. F. 

 James : The analytical representation of the theory 

 of congruences of conies. — Miss H. G. Telling : (a) 

 The geometrical theor>' of the apolarity of quadric 

 I surfaces, {b) A set of fifteen quartic surfaces in 

 : space of four dimensions, and the appUcation to the 

 theory of cubic surfaces in ordinary space. — J. P. 

 Gabbatt : The generahsation of the theory of the 

 circles associated with a triangle by means of the 

 theory of plane cubic curves. — B. M. Wilson: An 

 asymptotic relation between two arithmetic sums. 



Paris. 



Academy of Sciences, May 22. — M. Albin Haller 



in the chair. — The president announced the death 



of M. Laveran. — P. Urbain and G. Urbain : The 



extraction and purification of scandium from thor- 



NO. 2746, VOL. 109] 



veitite of Madagascar. This mineral, which contains 

 42 per cent of scandium oxide, is fused with soda 

 and the siUca removed by washing. The residue, 

 after dissolving in sulphuric acid, is treated with 

 hydrofluoric acid, which precipitates scandium and 

 rare earths aS fluorides. The scandium is separated 

 as acid sulphate after treating the fluorides with 

 sulphuric acid, and further purified by conversion 

 into the double sulphate of scandium and potassium. 

 — J. Costantin : The Maltese cross shown by wood 

 that has undergone traumatisms. An account of the 

 methods of wounding the stems of chestnut, sycamore, 

 and other plants for producing cross-like markings 

 on sticks to be used as canes or umbrella sticks. A 

 description is given of the changes produced by the 

 wounds in the stem. — J. Andrade : Three classes 

 of non - maintained vibratory movements. — S. 

 Sarantopoulos : Positive increasing functions. — Th. 

 Varopoulos : Some theorems of M. Borel. — R. 

 Nevanlinna : The relations which exist between 

 the order of growth of a monogenous function and 

 the density of its zeros. — E. Pagezy : The best 

 shape to give to propulsive helices. — P. Fatou : 

 The movement of a planet in a resisting medium. — P. 

 Chofardet : Observations of Skjellerup's comet made 

 with the coudS equatorial at the Observatory of 

 Besan9on. Positions for May 19 and 20 are given. 

 The comet was of about 12-5 magnitude, maximum 

 siz^e i', condensation uncertain. — A. Schaumasse : 

 Observation of Skjellerup's comet made with the 

 coude equatorial at the Nice Observatory. Position 

 given for May 19. The comet appeared as a diffuse 

 nebulosity about 2' in extent ; magnitude 12, feeble 

 condensation. — A. Andant : The variations of critical 

 opalescence with the temperature and the wave-length 

 of the incident light. Measurements were made on 

 five liquids of high critical temperatures — ether and 

 the acetates of methyl, ethyl, butyl, and isobutyl. 

 The phenomena observed in the case of ether are 

 described in detail. — E. Bauer : The electromagnetic 

 field of the stationary projectories of Bohr. — A. 

 Frigon : The experimental study of the energy losses 

 in some commercial dielectrics. — E. Berger : The re- 

 duction of oxides by hydrogen. Previous results 

 on the reduction of nickel oxide by the author and 

 Sabatier and Espil have not been in agreement, and 

 further experiments have now been carried out to 

 study the effect on the reduction of the mode of 

 preparation and dr3ang of the nickel oxide. The 

 velocity of reduction and form of the curve vary 

 with the origin of the sample of oxide, hence the 

 deduction of the existence of an intermediate oxide 

 from a kink in the reduction curve is not sound. — 

 A. Damiens : The " dynamic " allotropy of tellurium. 

 Cohen and Kroner have applied to tellurium a theory 

 of allotropy termed " dynamic," according to which 

 any homogeneous phase of a given body may be 

 composed of several species of molecules in equili- 

 brium. Experiments by the author on carefully 

 purified tellurium, crystallised, fused, and distilled, 

 do not confirm the views of Cohen and Kroner, 

 and all the phenomena observed can be easily 

 explained without the formulation of a new theory. 

 — A. Dauvillier : The L series of lutecium and of 

 ytterbium and the identification of celtium with the 

 element of atomic number 72. — G. Urbain : The 

 atomic numbers of neo-ytterbium, lutecium, and 

 celtium. From the high-frequency spectra it is 

 now possible to attribute without ambiguity the 

 atomic numbers of neo-ytterbium (70), lutecium (71), 

 and celtium (72). A translation of the paper ap- 

 pears on p. 781. — A. Boutaric and M. Vuillaume : 

 The flocculation of colloidal sulphide of arsenic. 

 The influence of the concentration of the colloid, 

 of agitation, and of temperature. The experimental 



