September 15, 192 1] 



HATURE 



97 



r'lve-year normal and only 34 per cent, of the average. 

 The next smallest total was 2-20 in. for East Eng- 

 and, which is 406 in. less than the normal and 

 35 per cent, of the average. At the English Channel 

 stations the total was 383 in., which is 252 in. less 

 than the normal and 60 per cent, of the average. 

 Bright sunshine was in excess of normal in all 

 districts except North Scotland, the greatest amount 

 of the possible duration being 53 per cent, at the 

 English Channel stations, followed by 47 per cent, 

 in South-East England and 46 per cent, in South- 

 West England. The Greenwich values for the civil 

 dav published in the weekly returns of the Registrar- 

 General give the average temperature, mean of 

 maximum and minimum, 64-2° F. for the three 

 summer months combined, the respective means being 

 June 603° P., July 685° P., and August 63-8° P. 

 The excess on the average for thirt}i--five years for 

 the whole summer is 22° P., for June 04° P., for 

 July 50° P., and for August 1-2° P. The rainfall 

 for the three summer months combined was 1 29 in., 

 the total for June being 046 in., that of July 015 in., 

 and that of August 068 in. The deficiency for the 

 summer on the average for 100 years is 542 in., and 

 the total is onlv 19 per cent, of the average. Smaller 

 falls have occurred previously in each month, but 

 onlv once in July, in 1825, when 010 in. fell. The 

 fall for the whole summer is the smallest in the 

 last 105 years, the next lowest being 1-36 in. during 

 the summer of 1818, followed by 2-50 in. fcM- 1864. 

 The sunshine for the three summer months at Green- 

 wich registered 222 hours in June, 286 hours in July, 

 and 179 hours in August, in all 687 hours, which is 

 92 hours in excess of the normal for the summer 

 season. 



Charts showing the deviation of the pressure and 

 temperature from normal values for each month and 

 for the year 19 10, based on observations at land 

 stations — generally two for each 10° square of lati- 

 tude and longitude — have just been published by the 

 Meteorological Office under the title of " Roseau 

 Mondial, 1910. " The charts have been prepared to 

 ■Ilustrate the tables which were issued in 1920, and 

 a similar volume of charts for 191 1 was published in 

 1916. The late war has rendered it difficult at 

 present to obtain data for the later years. This world- 

 wide meteorology will add much to our present know- 

 ledge of weather changes, which in many respects 

 are exceedingly intricate; it is by such world-wide 

 information that we may eventually hope to forecast 

 for longer periods than is possible at present, and in 

 ime, perhaps, we may foresee the character of a 

 coming season. Atmospheric-pressure lines of equal 

 deviation from normal are given for each five milli- 

 bars, and for temperature the individual deviations 

 are plotted for each station. In this volume it has 

 not been found possible to represent graphically the 

 deviation of rainfall from normal. Among many 

 other questions of interest, such charts may render 

 it possible to form some idea as to whether the pres- 

 sure of the atmosphere is always practically uniform 

 over the world as a whole; the charts in question 

 would seem to suggest that it is, but a more detailed 

 NO. 2707, VOL. 108] 



examination must be made to substantiate such a 

 conclusion. 



The September issue of the Philosophical Magazine 

 contains a paper on "The Effect of Temperature on 

 the Rigidity and Viscosity of Metals " by Messrs. 

 Kei lokibe and Sukeaki Sakai, of the University of 

 Sendai, Japan, which appeared in vol. 10 of the 

 Science Reports of that University. The method 

 used bv the authors is that of tcwsional oscillations 

 of a wire 25 cm. long and o-6 to 07 mm. diameter 

 suspended vertically in a tube furnace electrically 

 heated to 700^-800° C. In all the thirteen metals 

 tested as the temperature rises the rigidity decreases, 

 according to a parabolic law which would make the 

 value zero at the melting point. The decrease at low 

 temperatures is small for metals with high melting 

 points, but becomes rapid near the melting points in 

 all cases. The viscosity as determined on Honda's 

 theor}- from the logarithmic decrement of the oscilla- 

 tion increases rapidly as the temperature rises up to 

 the melting point, but in the case of metals with high 

 melting points there is a range of temperature below 

 100° C. within which the viscosit},- decreases slightly 

 with rise of temperature. 



In a note on p. 502 of Nature for June 16 we 

 directed attention to the conclusion of Mr. T. L. 

 Elckersley that the main source of the trouble in the 

 determination of the direction frcKn which a radio 

 message comes during the night is the wave reflected 

 downwards at the under-surface of an outer con- 

 ducting layer of the atmosphere. In the August issue 

 of the Radio Review Messrs. G. M. Wright and S. B. 

 Smith, of the Marconi Research Department, describe 

 observations on the night behaviour of the heart- 

 shaped polar diagram obtained bv combining a single 

 frame with a vertical aerial, and find that it agrees 

 with the reflected-wave theory. It shows further that 

 the reflected ray is in a vertical i>lane and that its 

 angle of incidence is small. In these circumstances 

 the minimum of the heart-shaped diagram gives the 

 correct bearing of the transmitting station, whether 

 night disturbances are present oc not. 



The paper on the magnetic electron which Prof. 

 A, H. Compton, of the University of St. Louis, con- 

 tributed to the American Association for the Advance- 

 ment of Science in December last is reproduced in the 

 August issue of the Journal of the Pranklin Institute. 

 After pointing out that Langevin's theor\- of diamag- 

 netism is inadequate quantitatively and makes dia- 

 magnetism transient instead of permanent. Prof. 

 Compton shows that the evidence is in favour of the 

 negative electric charge being the prime cause of the 

 magnetic property of the molecule. His own ob- 

 ser\'ations on the passage of X-rays through, and 

 their reflection from, magnetised crystals show no 

 evidence of the orientation of the molecules by the 

 magnetic field, which present theories of magnetisa- 

 tion postulate. He considers that the electron 

 spinning about an axis through itself like a small 

 g>TOstat is more likely to be the ultimate magnetic 

 particle than either the atom or the molecule, and 

 thinks that the spiral form of path which is so 



