November 24, 1923] 



NA TURE 



779 



being hastened by increasing the temperature. — 

 N. T. Belaiew :, On the genesis of Widmanstatten 

 structure in meteorites and in terrestrial alloys. The 

 Widmanstatten structure belongs to the triad of 

 secondary structures, the other two being the struc- 

 ture of large crystals and the network structure. 

 Under suitable conditions either of these structures 

 may occur in iron-carbon alloys or in any other 

 alloys crystallising in the face-centred cubic lattice 

 and exhibiting the same kind of equilibrium diagram. 

 As the diagram of the iron-nickel alloys is quite 

 similar to that of iron -carbon, the same kind of 

 crystallisation may be expected in both cases and 

 also in meteorites. The well-known Widmanstatten 

 figures in meteorites are also arranged in a Wid- 

 manstatten structure, and the conditions to which 

 they owe their appearance are a very slow cooling 

 after solidification in the granulation zone and a 

 relatively rapid separation of the constituents after- 

 wards in the zone of secondary crystallisation leading 

 to their lodging themselves parallel to the octahedral 

 planes in every granula. — L. R. Wilberforce : Illus- 

 tration and detection of inclined and horizontal 

 dispersion in bi-axial crystals. If the optic picture 

 of an ordinary bi-axial crystal is viewed through a 

 prism the refracting edge of which is parallel or 

 perpendicular to the axial plane, the appearances 

 characteristic of horizontal and inclined dispersion 

 respectively are produced. Such dispersions in a 

 crystal, if too small to be detected by direct observa- 

 tion, can be discovered by thus using a prism of small 

 angle alternately to reinforce and oppose them, and 

 noting the want of symmetry in the effects produced. 

 — A. Russell : On the occurrence of the rare mineral 

 nadorite in Cornwall, and of beraunite (eleonorite) in 

 Co. Cork, Ireland. A single specimen of the rare 

 mineral nadorite was found at the small antimony 

 mine Bodannon, St. Endellion, Cornwall. It forms 

 aggregates of nearly square platy crystals, trans- 

 parent, of a yellowish-brown to reddish-brown colour, 

 occupying a cavity in fibrous jamesonite. The 

 crystals are combinations of a (loo) and r (130) and 

 are twinned on / (on). A very well-defined specimen 

 of the variety of beraunite known as eleonorite, found 

 at the iron and manganese mine of Roury Glen, 

 Glandore, Co. Cork, consists of a mass of diverging 

 fibrous crystals of a reddish-brown colour, between 

 walls of limonite. The fibres are elongated in the 

 direction of the h axis and show very strong pleo- 

 chroism. — A. F. Hallimond and F. R. Ennos : On 

 stilpnomelane, from North Wales. A dark scaly 

 vein-mineral, strongly resembling biotite, proves 

 on analysis to contain very little p>otash, and is 

 very similar in physical properties to stilpnomelane 

 from Moravia. The composition appears to be 

 6SiO,-2Fe,Os-2FeO-3H20 ; sp.g. 285 ; apparently 

 uniaxial; 0=1-687, 6=1-595; pleochroic, o =:dark 

 brown, e =pale yellow ; brittle, with eminent basal 

 cleavage and marked cleavage normal to this, yielding 

 pleochroic chips; H =3-5 ; insoluble in hot N/2 HCl. 

 — G. T. Prior : On the chemical composition of the 

 Ashdon meteorite : This meteoric stone which fell 

 at Ashdon near Saffron Walden, Essex, on March 9, 

 1923, is a white hypcrsthcne-chondrite containing 

 8 J per cent, of oickehfcrous iron in which the ratio 

 of iron to nickel is about 6 to i . 



Cambridge. 



Philosophical Society, October 29. — Mr. C. T. 

 Heycock, president, in the chair. — W. J. Harrison : 

 On the motion of spheres, circular and elliptic 

 cvlindcrs through viscous fluid. — E. A. Milne : On 

 the derivation of the equations of transfer of radiation 



NO. 2821, VOL. I 12] 



and their appUcation to the interior of a star. — F. P. 

 White : (i) The conies through fives of six points. 

 (2) Certain nets of plane curves. — C. G. Darwin and 

 R. H. Fowler : Some refinements of the theory of 

 dissociation equilibria. — J. C. Burkill : The funda- 

 mental theorem of Denjoy integration. — -D. R. 

 Hartree : On the correction for non-uniformity of 

 field in experiments on the magnetic deflexion of 

 /3-rays. — T. M. Cherry : On the solution of certain 

 difference equations. — W. Burnside : On the formulae 

 of one-dimensional kinematics. — W. P. Milne : Note 

 on the twelve points of intersection of a quadri- 

 quadric curve with a cubic surface. — E. S. Bieler : 

 The effect of deviations from the inverse square law 

 on the scattering of a-particles. — W. M. H. Greaves : 

 The stability of the periodic states of the triode 

 oscillator. — D. Keilin : The structure and life-history 

 of Lipotropha n.g., a new type of Schizogregarine, 

 parasitic in the fat body of a dipterous larva (Systenus). 



Manchester. 



Literary and Philosophical Society, November 6. — 

 R. H. Thouless : The psycho-galvanic phenomenon. 

 The psycho-galvanic phenomenon is the change which 

 takes place in the bodily resistance during emotion. 

 It may be measured by placing electrodes on the 

 palm and back of the hand, and balancing the resist- 

 ance so obtained in a Wlaeatstone bridge circuit. 

 The threat to prick the subject with a pin may 

 produce a reduction of more than 1000 ohms in a 

 total resistance of 12,000 ohms. The exact physio- 

 logical change producing this result is not known, 

 but we are clearly measuring one of the many in- 

 voluntary bodily changes which accompany emotion. 

 One person may react much more readily than 

 another. Possibly this may be due to differences in 

 temperament or to such prosaic causes as differences in 

 the dryness of the skin. Similarly, differences in the 

 resistance changes of the same person on different 

 days are as likely to be due to simple physiological 

 changes as to differences in his mood. What may 

 reasonably be assumed is that one person during 

 the course of one sitting gives greater resistance 

 changes for greater emotion and vice versa ; though 

 after a resistance change, there is a long period of 

 slow recovery, and the extent of a new deflexion 

 probably depends in part on what stage in recovery 

 has been reached. 



Paris. 



Academy of Sciences, October 29. — M. Albin 

 Haller in the chair. — The president announced the 

 death of M. Maurice Leblanc, member of the section 

 for the application of Science to Industry. — J. 

 Costantin and L. Dufour : A secondary disease of 

 the oak caused by Polyporus {Phellinus) ritbriporus. 

 The growth of this fungus is very slow, attacking 

 the tree always near the soil level. Details are given 

 of thirty-two trees attacked by this disease. Owing 

 to its slow growth and the fact that the fungus 

 can enter the tree only at a damaged spot, the 

 disease is unlikely to prove troublesome. — Viggo 

 Brun : The direct study of Riemann's f{x). — A. 

 Guillet : The mechanical determination of the relative 

 course of two pendulums. A comparator with a 

 chronometric motor. — A. Damiens : The dynamic 

 allotropy of mercuric iodide. The author h<us repeated 

 some recent experiments of Smits and Bokhorst on 

 the change of the red into the yellow varieties of 

 mercuric iodide. While the experimental results 

 agree, under certain conditions, the author's inter- 

 pretation differs entirely from that of the above 

 workers. The necessity for a new theory of allotropy 



