740 



NATURE 



[February 3, 192 1 



ticulars of nearly a thousand books, maps, engravings, 

 and drawings relating to North America (United 

 States and Canada). Many items will be of interest 

 to readers of Nature, e.g. a number of works on the 

 Indian tribes of North America, Audubon's "The 

 Birds of America," the very rare book by T. Morton 

 entitled "New England Canaan, or New Canaan," 

 and the silver ticket of Benjamin Franklin's member- 

 ship of the Royal Society of Edinburgh. The cata- 

 logue will be sent free of ch^ge by the publisher. 



In the Fauna of British India Series the further 

 volumes which the editor, Sir Arthur E. Shipley, with 

 the assistance of Dr. Guy A. K. Marshall and 

 the sanction of the Secretary of State for India, has 

 arranged for are : Butterflies (Lycaenidae and Hes- 

 periidae), Mr. N. D. Riley; The I.xodidae and 

 Argasidae, Prof. G. H. F. Nuttall and Mr. C. War- 

 burton ; Leeches, Mr. W. A. Harding ; The Diptera 

 Brachycera, Mr. E. Brunetti ; The Operculata, Mr. 

 G. K.Gude; The Curculionidaj, Dr. G. A. K. Mar- 

 shall; The Carabidae, Mr. H. E. Andrewes; The 

 Meloidse, Mr. K. G. Blair; The Erotylidae and Endo- 

 mychidae, Mr. G. J. .A,rro\v ; The Culicidse, Capt. P.J. 

 Barraud, Major S. R. Christophers, and Mr. F. W. 

 Edwards ; The Chrysomelidae, Mr. S. Maulik ; The 

 Oligochaetae, Lt.-Col. J. Stephenson; Th* Scolytidae 



and Platypodida, Lt.-Col. Winn Sampson, together 

 with a revised edition of Mammalia by .Mr. Martin 

 A. C. Hinton and Mr. R. C. Wroughton, and of 

 Birds (4 vols.) by Mr. E. C. Stuart Baker. 



The list of new books and new editions added to 

 Lewis's Medical and .Scientific Circulating Library 

 during October to December, 1920, has reached us from 

 Messrs. H. K. Lewis and Co., Ltd., 136 Gower Street, 

 W.C.I. Although intended primarily for subscribers 

 to the library, it should be of great service to all 

 who wish to keep in touch with medical and scientific 

 literature, being practically a complete catalogue of 

 important books in English on medicine and science 

 issued during the period named. It is carefully 

 classified according to subjects, and will be sent gratis 

 upon application. 



Messrs. L. Oertling, Ltd., Turnmill Street, 

 London, E.C. i, ask us to announce that they are re- 

 commencing their service of attendance to balances 

 in customers' own laboratories throughout the United 

 Kingdom. This service was discontinued during the 

 war owing to the extreme pressure of work in the 

 firm's manufacturing departments and to the lack 

 of mechanics possessing the necessary technical 

 ability. 



Our Astronomical Column. 



Planets now Visible. — In the second week of 

 February all the bright planets will be visible to the 

 naked eye. Venus, Mars, and Mercury will be in 

 the western sky, while Jupiter and Saturn will appear 

 in the eastern. 



Mercury will be at greatest elongation on 

 February 15, when it sets about ij hours after the 

 sun. Venus will set on February 13 at 9.40 p.m., 

 and Mars at 8.32 p.m. On February 9 the crescent 

 of the new moon will be in conjunction with Mer- 

 cury, and with Mars on February 1 1 . Venus will 

 be a very conspicuous object, but Mars ■will appear 

 undulv faint, owing to its great distance from the 

 earth. 



Jupiter rises on February 14 at 7.33 p.m. and on 



February 28 at 



p.m., while Saturn rises about 



40 minutes later. These objects are situated in the 

 southern part of Leo, and will be in the same region 

 as the moon on February 23. 



The Diameters of Stars. — Popular Astronomy for 

 January states that the observations of the diameter 

 of Betelgeux were made on December 13 by Mr. 

 F. G. Pease and Dr. J. A. Anderson, the method 

 being due to Prof. A. .^. Michelson. The measured 

 diameter is given as 0-047''. 



Prof. H. N. Russell, before the result was known, 

 published the following estimates of the angular dia- 

 meters of the brighter red stars: — Betelgeux, 0031''; 

 ."Vntares, oo28" ; Aldebaran, 0024"; Arcturus, 0-019'; 

 /3 Crucis, 0026" ; and P Gruis, 0-020". All these 

 are within the range of possible measurement. The 

 angular diameters of the stars of types A, B, and F 

 are very much smaller (Sirius being 0-007"), a"<l there 

 is little prospect of success with them. 



It is of interest to note that the parallax of .Arcturus 

 has recently been redetermined at Yerkes Observa- 

 tory by Messrs. O. J. Lee and G. van Biesbroeck 



NO. 2675, VOL. 106] 



(Pop. Astr., January). The result, 0-095' ±0-006", is 

 larger than previous values. Russell's angular dia- 

 meter w'ould imply a linear diameter of one-fifth 

 astronomical unit, or twenty-two times that of the 

 sun. The thwart velocity would be 24 astronomical 

 units per annum, or 70 miles/sec. 



Minor Planets. — The remarkable body HZ was 

 observed at Algiers, January 12-3, in R.A. oh. i7-5m., 

 N. decl. 26° 52', mag. 138. The planet has now been 

 under observation for 2^ months, and the orbii 

 already published in this column, with perihelion 

 near Mars and aphelion near Saturn, is fully con- 

 firmed. Such an orbit is obviously of a cometary 

 character, vet careful scrutiny has failed to show any 

 sign of nebulosity. 



Nine hundred and thirty-three minor planets have 

 now received permanent numbers. The difficulty of 

 keeping such a large number under regular observa- 

 tion is considerable, so it is satisfactory to note that 

 tables giving the approximate perturbations by 

 Jupiter of about 100 planets have lately been pub- 

 lished in Astr. Nachr., which should be of great 

 assistance in preparing accurate ephemerides. One 

 planet in particular, 170 Maria, has been studied in 

 great detail by K. Boda (Astr. Nachr., 5080). This 

 belongs to the Hestia type (period about ^ of 

 Jupiter's), and has small eccentricity, but considerable 

 inclination. The tables are compared with observa- 

 tions from 1877 to 1916. The largest residuals 

 (Obs.— Tab.) are + 58" in 1889 and -50' in •IQ04. 

 Greater accuracy could not be attained without very 

 elaborate tables. 



The chief centres of minor planet observation 

 during the past vear have been Algiers (MM. Gonnes- 

 siat and Jekhowskv), Barcelona (Prof. Comas Sola), 

 Heidelberg (Dr. Max Wolf), and Hamburg. Mar- 

 seilles observatory has assisted by circulating observa- 

 tions and ephemerides. 



