226 



NATURE 



[December 14, h^i i 



'Ihe cutnct it travelling south-east through Virgo, and 

 rises about three o'clock in the morning. 



Observations op Comets. — In No. 4538 of the Atiro- 



notnischc Nachrichten I'rof. Barnard publishes the resuhs 

 of liis observations of Wolf's periodic comet (1911a) during 

 the present return. The observations were made with the 

 Yerkes 40-inch refractor, and show that the magnitude was 

 about 14-15, the diameter from 5' to 10*, and that the 

 comet was a small and indefinite, although not diffused, 

 object. 



Positions of comet 191 16 (Kiess), determined during 

 July 13 to August 10 at Leipzig, arc given by Dr. H. 

 .\aumann, who found the comet to be very diffuse and 

 changeable in appearance. 



In ^.'o. 4539 of the same journal Dr. Backlund discusses 

 — rved and calculated places of Encke's comet 

 (luring the present apparition, with special refer- 

 . in;>> 10 the question of acceleration and the mass of 

 Mercury adopted in calculating the perturbing forces. 

 Prof. Konkoly records the wave-lengths and intensities of 

 the four bands 560, 546, 516, and 472 observed in Brooks's 

 and Beljawsky's comets, showing that the second and 

 fourth of these were relatively faint in Beljawsky's comet 

 at the time of observation. Only the first, third, and 

 fourth of these bands were recorded in the spectrum of 

 Qu^nisset's comet on October 14. 



In the Gazette Astronotnique (Nos. 47-48) are reproduced 

 drawings, made by M. Biesbroeck at Uccle, of comets 

 191 ic, 191 1/, and 1911^ on October 17; the differences in 

 form are very striking. That of Brooks's comet (1911c) 

 is of the Morehouse type, with long envelopes developed in 

 front of the nucleus sweeping out into a long, fairly 

 narrow tail. The form of comet 1911/ (Qu6nisset) is very 

 different, the tail being emitted as a narrow straight jot 

 from a point at the centre of the rear of the head. In 

 Beljawsky's (1911^) we recognise the type of envelope seen 

 ill th' case of comet 19100, where the nucleus was located 

 ^lii^litly within the front surface of a broad parabolic 

 envelope. 



The Distribution of Stars of Different Spectral 

 Types.-— Dr. Karl-Gustav Hagstrom publishes the results 

 of an interesting investigation concerning the distribution 

 of stars in space, from the point of view of their spectra, in 

 No. 7, vol. xlvi., of the Kungl. Svenska Vetenskaps- 

 akademiens Handlingar. He finds that his class a (fifth- 

 type stars) shows a marked concentration about the equator 

 of the Milky Way, and that his /3 type (Orion stars) are 

 more numerous and more concentrated in the southern than 

 in the northern hemisphere; but for solar and first-tvpe 

 stars, also for the later types, he can find no preferential 

 grouping. Accepting Herschel's idea that the visible stars 

 form a single system, and admitting that the non-con- 

 centrated types are inside the ring of such a system, it 

 would appear from this investigation that the system is 

 lenticular in form, the cooler redder stars being situated in 

 the neighbourhood of the sun, and the hotter stars in the 

 edge of the lens form. As the hotter stars also appear to 

 be in the southern hemisphere, it would seem that the sun 

 is located in the northern part of this stellar system. 



Determination of Radial Velocities.— An important 

 contribution to the study of stellar radial velocities appears 

 in vol. X. of the Annals of the Cape Observatorv— Spectro- 

 scopic Researches. It contains the results of the measure- 

 ment and discussion of radial-velocity plates taken between 

 November 7, 1903, and .May 4, 1908, and deals with thirtv- 

 one stars of the third magnitude and brighter. The 

 measurements of each line on each plate, and the wave- 

 lengths of the comparison spectra, are very fully discussed, 

 and it is shown that there is apparently a distinct varia- 

 tion of wave-length with spectral type, the thirtv-one stars, 

 for this purpose, being arranged in six successive groups. 

 \ comparison of the Cape results with those published, for 

 the s^me stars, by other observatories is reassuring con- 

 cernmg the general trustworthiness of radial-velocity 

 results ; thus eleven out of the thirteen results given for 

 a Tauri, determined at six different observatories, all lie 

 between 51.7 and 559 km. per sec. 



Early Methods of Determining Latitude.— Among the 

 publications of the Deutsche Seewarte of the Kaiserliche 

 ^Marine at Hamburg has recently appeared a memoir 

 NO. 2198, VOL. 88] 



entitled " Die Geschichcliche Entwicklung dcr Po 

 bestimmungen bei den alteren Volkern," by <":'■ 

 It contains a history of the various methods > 

 ing geographical latitude employed by the ' 

 noni'Ts to about the date 1350. The author makes : 

 original contribution to our sources of knowledge ; but ! 

 has made a careful survey of the e.\: ices and t) 



work of modern sicholars, and his ' y coounet. 



with numerous f •• ■ - .1.....1.1 1 , ^j,. ,^j, ^J those »! 



arc interested in le of the subject. 



The memoir r. ■ rs, of which the fu 



deals briefly with the earli 't<i at a solution of t; 



problem, especially amon,. ' liinese. The %fCf 



chapter relates to the Greek astronomers, from K' 

 to Ptolemy; in this period we find the earliest recc 

 of the change of latitude with locality. '! ' 

 of Indian astronomers, which is next d< 



seem to have advanced the methods of . ......->;., . 



was of the greatest importance in the development ' 

 trigonometry. 



The last two chapters treat of the work of the \t 

 astronomers AI-BattSni, Ibn Junis, and j\bul Hassan, 

 Morocco. The medizeval Arabs inherited the kno 

 acquired by the Greeks and the Hindus, and are kn 

 have possessed translations of the works of 1 

 Ptolemy, and Brahmagupta. But they also made : 

 progress on their own account. .Abul Hassan, in part 

 shows the greatest fertility of resource in inventing n- 

 methods, and succeeded in solving the most complicat. 

 problems in dialling. This, at least, would appear fr< : 

 his work; but, naturally, it is impossible to estimate l: 

 debt which he owed to his predecessors. 



Stars having Peculiar Spectra. — While examining t! 

 photographs of the Henry Draper Memorial, the late Mi 

 Fleming discovered an immense number of variable st;i 

 and other objects having peculiar spectra, and the fin 

 have been from time to time recorded in the Harvn: 

 College Observatory Circulars. No. 167 of these probalVi 

 completes the record of Mrs. Fleming's discoveries, and 

 contains a list of thirty-one new variables, of which thirteen 

 were found by her. It also gives a list of seven stn: 

 having peculiar spectra, of which Mrs. Fleming discover 

 five; in three cases Hi8 is bright, three others cont:i 

 bright lines, one being a gaseous nebula, and the other h 

 a normal fourth-type spectrum. 



The Evolution of Multiple Stars. — The question ct 

 the evolution of double and multiple star systems is dis- 

 cussed, in the light of recent discoveries, by Dr. See ' 

 No. 4539 of the Astronomische Nachrichten. Inter alia, 1 

 states that such systems, having developed from spir 

 nebulae of vast extent and slow motion of revolution, shoi: 

 show but little relative motion, and suggests that in siir 

 cases as $ Cygni, a Tauri, &c.. an effort be made to phot 

 graph the extremely faint residual nebulosity which, accoi 

 ing to the hypothesis, may >till surround the members > 

 such systems. 



MATHEMATICS IX ENGLISH SCHOOLS. 

 'T'HE powerful and vigorous article on " Mathematics ' 

 English Schools " contributed to Science Progress (■ 

 October by Mr. Charles Godfrey, headmaster of the Roy 

 Naval College, Osborne, opens up a subject deserving t: 

 most attentive study on the part of everyone who is int« 

 ested in the future progress of our race. .As the author 

 points out, modern civilisation stands on a foundation of 

 applied mathematics ; without mathematics the earth couH 

 not support its present population. But in England v 

 have a ruling class whose interests are sporting, athlet; 

 and literary ; consequently not only is mathematics not 

 bread-and-butter subject except for those who are satisfi' 

 with this simple diet, but the work of the mathematici. 

 is ignored and even treated with contempt. .And this 

 spite of the fact stated by Mr. Godfrey, that mathemati. 

 occupies a larger share of time in our school curricu. 

 than in those of other countries. The remedy proposed !■ 

 Mr. Godfrey is that our teaching in schools should be based 

 on the " outlook " value of mathematics, and should train 

 our boys to appreciate the tremendous potentialities of t! 

 subject of which they are mastering the elements. A 



