73S 



NATURE 



[November 17, 1923 



will \yc included much fresh material and many 

 illustrations reproduced from medieval originals. 

 The work will treat of mining, quarrying, building, 

 metal-working, pottery, clothmaking, leather-work- 

 ing, fishing, brewing, and the control of industry. 



The latest catalogue (No. 228) of Messrs. W. 

 Hefler anci Sons, Ltd., Cambridge, is an important 

 one. It contains upwards of 1300 titles of second-' 

 hand works classified under the following headings : 

 scientific periodicals and transactions of scientific 

 societies, standard scientific books, standard sets 

 and periodicals in English, historical and general 

 literature, foreign literature, oriental literature and 

 journals, and addendum. 



The new announcement list of Messrs. Longmans 

 and Co. gives particulars of the three following 

 books which should be of interest to engineers : 

 " Reinforced Concrete Design," by G. P. Manning, 

 in which the subject-matter is treated from the 

 point of view of the engineer designer. It will 

 include the theory and practice of design as generally 

 admitted and employed at the present day ; " AppHed 

 Elasticity," by Dr. J. Prescott, written to fill a gap 



which has existed between the two extremes <<t 

 English text-books on elasticity. Strict math - 

 matical methods are used wherever these are n it 

 too cumbersome, and approximate methods n-"- ■ ' 

 to simpUfy the cumbersome methods; an 

 Principles of Irrigation Engineering, with spc 1 u 

 reference to South Africa," by F. E. Kanthack. 



Messrs. Edward Arnold and Co. announce the 

 early publication of " Outlines of Palaeontology," by 

 Prof. H. H. Swinnerton. of the University College. 

 Nottingham, in which palaeontology is dealt with as a 

 definite branch of science and not as an adjunct to 

 stratigraphical geology, or as a mere di\ 

 zoology. The method of treatment adopt* 

 from the difficulty felt by students of geology a 

 zoology and by others interested in the problems ..f 

 animal life and evolution in past ages in being able to 

 visualise all the salient characters for which a number 

 of generic or specific names stand sufficiently clearly 

 and completely for the purpose of making mental 

 comparisons. This fact has been borne in mind by 

 the author, and consequently most problems are dis- 

 cussed in terms of organs and structures rather than 

 of organisms and species. 



Our Astronomical Column. 



Two Comets. — A telegram from the Cape announces 

 that Comet Doubiago-Bernard has been observed 

 there, and that the following orbit has been deduced : 



T = i923, Nov. 17-70 

 w=254° 32' 

 fi=227 36 

 i=ii4 17 

 log ^=9-8976 



The comet will return north early next year and may 

 p>ossibly be visible with large instruments in February 

 and March. It travelled to nearly 70° S. Decl. 



Herr Reinmuth, assistant to Prof. Max Wolf 

 at Konigstuhl, Heidelberg, detected a cometary 

 object on October 31 at S*" 44-5"' local M.T. in 

 R.A. ih 15"' 4», N. Decl. 22° 31'. Daily motion is 

 probably - 32*^, north 28', but as the discover^' was 

 made photographically the motion may possibly have 

 been in the reverse direction. The photographic 

 magnitude is given as 13-0. The discovery was made 

 in the course of the minor planet work that is regularly 

 carried on at Konigstuhl. 



Polarities of Sunspots. — Much interest was 

 caused at the meeting of the Royal Astronomical 

 Society on November 9 by the reading of notes by 

 Prof. Hale and Mr. Ellerman announcing that the 

 Mt. Wilson observations confirmed the reversal of 

 the polarity law for the constituent spots of double 

 groups in the sunspots of the new sunspot cycle. 

 The evidence now suggests that the law persists 

 throughout one 11 -year cycle, and is reversed for the 

 following one. 



Prof. Newall pointed out that this means the 

 substitution of a 2 2 -year cycle for solar changes, 

 instead of the previously accepted 11 -year cycle. 

 He noted that the discovery increased the difficulty 

 in obtaining a mechanical explanation of sunspot 

 phenomena, since the magnetic polarities depend on 

 the directions of the vortex motions round the spots. 



The Fireball of November 3. — This object was 

 observed at 6.53 p.m. at Bristol, Bodmin (Cornwall). 



NO. 2820, VOL. I 12] 



and other places, though very few observations of a 

 satisfactory kind have come to hand. Mr. W. F. 

 Denning writes that the real path of the object was 

 directed from north to south, the beginning of the 

 luminous course of the meteor being over the reuuni 

 of Torquay, and the end over the English Channel 

 about 64 miles S.S.E. of Start Point. The radiant 

 point was at 160° +59° near /3 Ursae Majoris. from 

 which point a bright meteor was also seen on 

 October 14 last. This shower app>ears to be con- 

 tinuous during the last three months of the year. 

 In any case it has been repeatedly observed from 

 the second week of October up to the last week in 

 December. 



In the spring months of March and April the same 

 radiant in Ursa Major is manifested with great 

 distinctness. This long continuance or frequent 

 repetition in meteoric radiation deserves further 

 investigation. 



Sunspots and Changes in Solar Radiation. — 

 Prof. Abbot's announcement of the short-period 

 changes in solar radiation was made several years ago. 

 He examines (Proc. Nat. Acad. Sci., U.S.A., Oct. 

 1923) how far a connexion can be traced between 

 visible changes on the solar disc and the radiation 

 changes. His results are as follows : 



1. The appearance of sunspots is accompanied by 

 high radiation, presumably owing to the uprush of 

 hotter matter from the interior. 



2. Lower radiation generally occurs just after the 

 central transit of spots. 



3. Generally a disturbed solar surface means high 

 radiation, a quiescent surface low radiation. 



With regard to (2), he refers to Guthnick's observa- 

 tions of the brightness of Saturn. The fluctuations 

 could be made to accord with the variations of 

 radiation, on the supposition that the radiation is 

 different in different directions, a time-correction 

 being necessary for the difference of longitude of the 

 earth and Saturn. It is suggested that above sun- 

 spots there are veiling rax^s, analogous to the coronal 

 rays, which cause absorption of radiation. 



