July 14, 1923] 



NA TURE 



65 



' The new catalogue of second-hand books (No. 225) 

 of INIessrs. W. Heffer and Sons, Ltd., Cambridge, is 

 of a miscellaneous character, but it contains many 

 works likely to be of interest to readers of Nature, 

 e.g. those dealing with folk-lore, occult literature, 

 and Egyptology. A useful section is that devoted 

 to foreign literature. 



Messrs. Negretti and Zambra, of 36 Holborn 

 Viaduct, London, E.C.i, have recently sent us a 

 spirit thermometer of a useful pattern for indoor 

 use. It is mounted on a metal frame, the graduations 

 in degrees Fahrenheit being black on a white ground. 

 The bulb is protected by a strong guard made as a part 

 of the frame. 



Mr. Valentine Davis, of Noddfa, Wistaston, 

 Crewe, is organising a holiday course in Chamonix, 

 on August 17-September I. It is proposed to make 

 excursions to various glaciers and passes, using 

 Chamonix as headquarters, and the flora of the 

 district, the geology of Mont Blanc, and similar 

 field-studies will be made. Particulars can be 

 obtained from Mr. Davis. 



Messrs. George Routledge and Sons, Ltd., 

 have ready for publication part 3 of the third 

 edition of Sonnenschein's " The Best Books : a 

 Classified Bibliography." It deals with history 

 and biography, and historical collaterals, and con- 

 tains particulars of some 24,000 books. The fourth 

 and concluding part will, it is hoped, be published 

 at the close of the present year. It will deal with 

 the sciences, industries, arts, literature, and 

 philology, and contain complete indexes of authors 

 and subjects. 



Dr. W. Brown is bringing out through the Uni- 

 versity of London Press, Ltd., under the title of 

 " Talks on Psychotherapy," the course of lectures 

 recently delivered by him at King's College, London. 

 It will deal with the subjects of functional nerve 

 disease, psycho - analysis, abreaction and trans- 

 ference, the libido theory and melancholia, auto- 

 suggestion, etc. Other books to be published by 

 the same house are three by Dr. Cyril Burt on " The 

 Sub-Normal School Child," entitled respectively 

 " The Young Delinquent," " The Backward and 

 Defective Child," and " The Unstable and Neurotic." 



Our Astronomical Column. 



Correction to the Longitude of Bordeaux 

 Observatory. — A note in the Journal des Observa- 

 teurs for June, by J. Trousset and L. Gramont, 

 contains the rather surprising announcement that 

 the accepted value of the longitude of the Bordeaux 

 Observatory is a second of time in error. This was 

 based on an elaborate determination, made in 1881 

 by MM. Rayet and Salats, both observers and 

 instruments being interchanged. The amount is 

 altogether beyond the probable error of the determina- 

 tion, and presumably arose from some systematic 

 error in marking the seconds on the chronograph 

 tapes, or some similar cause. 



The error was detected by the reception of the 

 Paris wireless signals at Bordeaux, and a new deter- 

 mination of the longitude was then made by means 

 of these signals. The resulting value of the longitude 

 of Bordeaux west of Greenwich was 2'" 6-564^ the 

 mean error being o-023^ The old value, printed 

 in the Nautical Almanac, is 2'" 5-51'. 



The new determination, though only just published, 

 was made in April and May 1921 ; presumably it 

 was in use throughout 1922 in the wireless time 

 signals sent out from Bordeaux and received at 

 Greenwich. The mean difference between the Green- 

 wich times of receipt of the Paris and Bordeaux 

 signals was only o-04^ 



Silicon Lines in B-type Stars. — In the deter- 

 mination of the radial velocities of B-type stars, the 

 wave-lengths of the lines of silicon are constantly 

 being used, but the values employed have not been 

 referred to modern standards of wave-lengths. The 

 lines in the spectrum of silicon alter as the tempera- 

 ture is increased and the enhanced or ionised lines 

 occur as doublets and triplets alternately and are 

 known as Si II, Si III, and Si IV as first differentiated 

 by Sir Norman Lockyer. A new determination of 

 the wave-lengths of those lines has just been com- 

 pleted by Mr. H. Barrell in the laboratory of Prof. 

 Fowler (Mon. Not. R.A.S., vol. 83, p. 322), and he 

 gives both the adopted values in International Units 

 and in Rowland's scale. While the instrument 

 employed in the determination was not the one that 



NO. 2802, VOL. I 12] 



was most desired, since the latter is still in detention in 

 Russia, that employed gives, as is stated, " the desired 

 redeterminations with every possible precaution to 

 ensure a high degree of accuracy." As the silicon 

 wave-lengths are in very general use it is important 

 that these new values should be widely known ; they 

 are briefly summarised below : 



Group 

 of lines. 



Si II . . 



Si III 



SI IV 



A Variable of Very Short Period. — Mr. F. C. 

 Jordan, of Alleghany Observatory, contributes a note 

 to Astron. Journ., No. 821, on a star of magnitude 

 about 1 1 J, on the same plate with the Cepheid 

 variable S Comae ; the period of light-variation is 

 only 2'* 50-8'", the light-range being 0-73 mag. The 

 light-curve is very pointed at minimum, there being 

 no stationary interval. There is none at maximum 

 either, but the curve is here rounded, not pointed. 

 From comparison with some similar curves it is 

 thought likely that the star is of the Beta-Lyroe 

 type rather than the Algol type ; in this case the 

 period will have to be doubled. The two portions 

 of the curve are so alike that in this case the two 

 stars must be very similar in size and brightness. 

 It is feared that the star is too faint to decide the 

 matter by spectroscopic determinations of the radial 

 velocity. 



The approximate position of the star for the equinox 

 of 1900 is R.A. I2'> 28"' 4s, N. Decl. 27° 16-1'. 



