October 7, 1920] 



NATURE 



191 



tracks of the centres of 620 typhoons which have 

 been reported in the Far East during the twenty-six 

 vears, 1893-1918. The original purpose of the author 

 as to issue these charts as an appendix to a more 

 general study of the subject, but since the publica- 

 tion of this more comprehensive report has beeo con- 

 siderably delayed, it was decided that the appendix 

 should appear at once. Consequently, the atlas con- 

 ins little more than the charts themselves, with 

 rief explanatory notes on each. It lays no claim to 

 :><; a theoretical treatise on the structure and origin 

 .f these revolving storms. No attempt at classifica- 

 tion is made, since the charts are intended solely for 

 I he nautical guidance of sailors. The cases are 

 -numerated month by month as they occur, and to 

 .ivoid confusion and overlaf>ping of the tracks, three 

 charts are allotted to each of the months of maximum 

 frequency (July to October inclusive). The maps 

 cover a wide geographical area, from Cochin China 

 and the Philippines in the south, to Manchuria and 

 the Kurile Islands in the north, while embracing a 

 vast stretch of the Pacific eastwards from the .Asiatic 

 mainland to 150° E. longitude. The irregular west- 

 south-westerly motion of occasional storms in this 

 region— chiefly in the China Sea— is clearly shown in 

 the charts, and the author lays stress on the point 

 that navigators should be familiar with the possibility 

 of this unusual movement, even though the vast 

 majority of the storms follow a general norlh-westerly 

 track, such as is customary in the northern hemi- 

 sphere. In conclusion, twelve summary maps are 

 jjiven, showing the dangerous zones and the succes- 

 sive changes which take place throughout the year. 

 The atlas is of additional value in that it gives a 

 trustworthy and up-to-date measure of typhoon 

 frequency. 



We have received a copy of Catalogue No. 23 of 



ond-hand books in science just issued by Mr. R. S. 



•impton, 37 Fonthill Road, Finsbury Park, N.4. 



I he works listed (some 1100 odd) range over most of 



\\v "icifnces, and the prices asked are very reasonable. 



Th. italogue will be sent free upon application. 



Dr. Walter Kidd is publishing through .Messrs. 



11. F. and G. Witherby a work entitled "Initiative in 



Involution," which will contribute to the evidence in 



'i\our of Neo-Lamarckism, and give especial con- 



!' ration to the arrangement of the hair in 



iinmals. Messrs. Witherby also give notice of " k 



■ turalist in Himalaya," by Capt. R. W. G. Hing. 

 n, in which attention is given, among other sub- 

 is, to geometrical spiders and their work, various 



• cies of ants and their organisations, and the nesting 

 tincts of birds. 



Thb reviewer of "Smithsonian Meteorological 



I ibles " in Nature of .September 30, p. 142, stated 



It the Tables are not obtainable in the ordinary 



'V. .Messrs. W. Wesley and Son, 28 Essex Street, 



■ and, W.C.2, remind us, however, that they arc 



agents for the Smithsonian Institution in London, 



I that the Tables can be purchased from them. 



1- Tables form vol. Ixix. of the Smithsonian Mis- 



lancous Collections, and not vol. lix., as given at 



tin head of the review. 



NO. 2658, VOL. ro6] 



Our Astronomical Column. 



Prof. PicKERi.NG'b Lln.vk Observ.\tio.\s. — Prof. 

 W. H. Pickering has for many years been making a 

 careful study ot certain lunar tormations under all 

 angles of illumination, finding striking changes of 

 relative luminosity of adjacent markings in the course 

 of the lunar day, which he ascribes to the presence of 

 snow or hoar-frost, or in some cases to vegetation. 

 There can be only one opinion as to the interest and 

 value of the observations, whether Prof. Pickering's 

 conclusions are accepted or not. His latest study 

 (Popular Astronomy, August and September) is of the 

 region round the crater Conon in the -Apennines and 

 the neighbouring formation of Bradley. He asserts 

 that this region contains snowfields, clouds, and tracts 

 covered with vegetation. He distinguishes the clouds 

 from the snowfields as being more yellowish, less 

 brilliant, and more subject to change. One note that 

 he makes about them would seem to throw some doubt 

 on their assumed nature. " No clear evidence of 

 motion due to wind has ever been seen in the lunar 

 clouds, which apparently merely form and dissolve in 

 situ." The white snow-patches, on the other hand, 

 which appear hazy at sunrise, are stated to show 

 some drift; the "vegetation" regions darken con- 

 spicuously as the sun rises higher upon them. The 

 author asserts that volcanic activity is by no means 

 extinct on the moon, the floor of Plato being stated 

 to be an active region emitting many steam- 

 jets. 



There cannot be much doubt about the relative 

 change of brightness of the different markings, but 

 it does not apf)ear that the author has given enough 

 consideration to the possibility that it may arise from 

 differences in the composition of the rocks or of their 

 degree of slope and of smoothness. While the occur- 

 rence of snow, cloud, and vegetation cannot be ruled 

 out as impossible, it is at least somewhat difficult to 

 reconcile with the tenuity of atmosphere that is 

 demonstrated by the practical absence of refraction in 

 occultations and eclipses. 



The Sun's Magnetic Field.— The Observatory for 

 September contains an article by Dr. F. H. Seares, 

 written at Prof. Hale's request, giving an account of 

 the researches made at Mount Wilson since 1908 on the 

 sun's magnetic field. The investigation was suggested 

 by the discovery of the 2^man effect in the spectra 

 of sun-spots, which were surrounded by hydrogen 

 vortices. In the case of the general field the spectral 

 shifts are extremely minute, less than one-thousandth 

 of an angstrom, and it is only the remarkable accord- 

 ance in the results that gives confidence that the effect 

 is a real one, the shifts being of the same order as 

 accidental errors in the measures. The precaution 

 was taken that the measurer should not know in 

 which direction the shift on any plate was likely 

 to be, so that all bias was eliminated. Comparatively 

 few of the spectral lines were found to be suitat>le 

 for the research, and the results depend chiefly on 

 iron and chromium lines. A first solution showed 

 that the northern hemisphere had negative polarity, 

 and that the magnetic axis was close to the rotational 

 one. It was afterwards found that the inclination of 

 axes is about 6°, and that the magnetic axis revolves 

 about the other in 31-44 days. The investigation 

 indicates that the field strength diminishes rapidly 

 with increasing elevation, falling from 50 to 10 gausses 

 in 200 km. It will be noted that th<> shifts in this 

 investigation are much smaller than in the Einstein 

 spectral test; but differential measures suflfire 

 here, while in the nthrr i.t-c .ihsoltite anr< are 

 required. 



