794 



NA TURE 



[December 9, 1922 



Societies and Academies. 



London. 



Royal Society, November 23. — Sir Charles Sherring- 

 ton, president, in the chair. — T. E. Stanton : On the 

 characteristics of cylindrical journal lubrication at 

 high values of the eccentricity. The arc of contact 

 of the film was limited in extent in the experiments 

 and the intensity of pressure was considerably higher 

 than in normal practice ; the arcs of contact varied 

 from 14 to 35 degrees and the maximum intensities 

 of pressure from 1-4 to 3-5 tons per sq. inch. In all 

 the cases observed, the pressure distribution in the 

 film has been in accordance with the hydrodynamical 

 theory of Osborne Reynolds. By means of a careful 

 determination of the pressure distribution in the film, 

 and a measurement of the radius difference of bearing 

 and journal, sufficient data have been obtained to 

 calculate the viscosity of the lubricant and the atti- 

 tude and eccentricity of the bearing. The values of 

 the viscosity of the lubricant so calculated were in 

 good agreement with those determined in a visco- 

 meter, and it was concluded that the calculated 

 values of the eccentricity were trustworthy. In the 

 case of a journal 2-5 cm. diameter, the least distance 

 apart of the surfaces was found to vary from 0-0012 

 to 0-0024 mm - — J- H. Jeans: The propagation of 

 earthquake waves. Earthquake waves are regarded 

 as being compounded of a number of free vibrations 

 of a non-homogeneous gravitating earth. In 1885, 

 Lord Rayleigh discussed a certain type of surface 

 waves which would travel over _the earth's surface 

 with a velocity of about 0-92 \/(m/p). It is now 

 shown that there are additional, and far more numer- 

 ous, surface waves which travel with velocities VWp) 

 and \/((X +2/x)lp). If such waves are generated by 

 an earthquake at any point close to the earth's 

 surface, they will refocus themselves upon this point 

 after intervals which are integral multiples of 

 27r« v /(p//x) and 2Tra- s /{p/(\+2n)), the numerical values 

 of these quantities being about 223 and 126 minutes 

 respectively. In 191 7, two series of earthquakes, 

 each originating from the same centre, had their 

 times given approximately by formula? of the type — 



t = t +«,x 125-8 +n 2 x 222 -o minutes. 

 It is possible that the return of waves sent out by 

 one shock may produce a second shock by a kind of 

 "trigger" action. — F. A. Lindemann and G. M. B. 

 Dobson : A theory of meteors and the density and 

 temperature of the outer atmosphere to which it 

 leads. All major meteoric phenomena can be 

 accounted for consistently if the luminosity of the 

 meteor be attributed to the collision of volatilised 

 meteoric vapour with the air molecules. From 

 observed meteoric data the density of temperature of 

 the air at great heights is derived in four independent 

 ways which give consistent results. The density 

 above 60 km. appears to be very much greater than 

 corresponds to an isothermal atmosphere at 220° 

 Abs., and the temperature appears to be in the 

 neighbourhood of 300 Abs. The radiative properties 

 of ozone may account for this high temperature. — 

 F. C. Thompson and E. Whitehead : On the changes 

 in iron and steel at temperatures below 280° C. 

 Iron shows abnormalities of rate of increase of 

 electrical resistance and electric potential against 

 platinum at well-marked temperatures. Below 280 

 C. these temperatures are: 55 , 100°, 120 , 140°, 220°, 

 and 245 C. Of these, those at 120° and 220° C. are 

 the most important. Under the same conditions, 

 carbide of iron possesses two well-marked points at 

 160 and 200 C. These may be distinct points, or 

 the ends of a single transformation range. The 



NO. 2771, VOL. I 10] 



etching of cementite has been studied. Broadly the 

 reagents which darken cementite are strongly alka- 

 line ; no acid and only one neutral solution will do 

 this. A solution has been discovered which will 

 enable the two forms of cementite to be differentiated 

 micrographically, but since fi-cementite will change 

 to the a form in a few days at room temperature, this 

 etching is not always satisfactory. When samples of 

 iron and high carbon steel are quenched from 280 C, 

 the electrical resistivities differ from those obtained 

 by slow cooling. As the material tempers these 

 values gradually alter, till after some days they 

 practically coincide with those obtained by slow 

 cooling. — C. F. Jenkin : The fatigue failure of metals. 

 A theory of the mechanism of fatigue failure in metals 

 is offered. The theory is demonstrated by a simple 

 model which possesses the assumed properties of the 

 crystals forming the metal. The model, when tested 

 like a metal test-piece, gives stress/strain curves, 

 hysteresis loops, and the complete series of fatigue 

 ranges of exactly the same character as those given 

 by the metal test-piece. A method of mechanically 

 treating a mild steel test-piece is described, which, 

 according to the theory, should raise its fatigue range 

 about 20 per cent. ; another treatment is described 

 which should lower the fatigue range of medium steel 

 by about 25 per cent. — S. Brodetsky : The. line of 

 action of the resultant pressure in discontinuous fluid 

 motion. The general solution of the problem of dis- 

 continuous fluid motion past any barrier can be 

 expressed in terms of the variable introduced by 

 Levi-Civita, by means of which the part of the barrier 

 in contact with the moving fluid is transformed into 

 a semi-circle. The form of the barrier is defined by 

 the coefficients in a Taylor expansion. Although the 

 components of the resultant pressure on the barrier 

 have been calculated in terms of these coefficients, the 

 line of action has not been found previously. The 

 moment of the resultant pressure about a certain 

 point is a simple function of the first four coefficients 

 of the above expansion. — R. A. Houstoun : An in- 

 vestigation of the colour vision of 527 students by 

 the Rayleigh test. Lord Rayleigh discovered in 1881 

 that if homogeneous yellow is matched with a mixture 

 of homogeneous red and homogeneous green, some 

 persons require much more red, others much more 

 green in the mixture than the normal. Such persons 

 have been called " anomalous trichromats." Appar- 

 atus similar to Ravleigh's was employed in the 

 present survey. In the case of the 104 women, the 

 frequency curve is almost a perfect case of normal 

 variation ; in the case of the men, the normal curve 

 is present, and outside it lie the colour blind and the 

 anomalous trichromats ; the anomalous trichromats 

 are much fewer in number than would be expected 

 from Rayleigh's original paper. 



British Mycological Society, November 18. — Mr. 

 F. T. Brooks, president, in the chair. — M. C. Rayner : 

 Calluna " cuttings." Adventitious roots produced 

 from the leafy region of the stem showed infection 

 by the mycorrhizal fungus from the shoot tissues. 

 The results are completely at variance with those 

 of Christoph. — Miss G. Gilchrist : Bark canker 

 disease of apple caused by Myxosporium corticolum. 

 The disease is characterised by the formation of 

 large longitudinal scars on the sides of branches 

 which increase rapidly towards the end of summer, 

 and the production of wound gum. The fungus 

 seems to be a weak parasite, except under certain 

 conditions when the trees may be killed outright. 

 Infection may occur from a dead spur, grafting 

 wounds or from the region of the ground. — R. J. 

 Tabor : A new fungal disease of cacao and coffee. 

 The fungus, which is • a Phycomycete, shows the 



