May 5, 1921] 



NA 



3'*^ 



manufacture. The prices seem very moderate, and 

 the construction and sensibility of the instruments are 

 such as will make them suitable for teaching purposes 

 in schools. 



Beginning with the number to be published on 

 July 15 next, the Psychic Research Quarterly will be 

 incorporated in a new quarterly review entitled 

 Psyche, which will deal with applied and general 

 psychology in relation to education, psycho-analysis, 

 industry, religion, social and personal relationships, 

 psychical research, etc. A special feature of the 

 periodical will be the literary section. The publishers 

 will be Messrs. Regan Paul and Co., Ltd. 



The first number of a new publication. State 

 Technology, has been received. The journal is to b^ 

 the official organ of the Institution of Professional Civil 

 Servants, which was founded in 1918. A novel feature 

 of the first issue is the inclusion of short abstracts of 

 the proceedings of technical institutions and a paper 

 on a technical subject. The journal will thus assist in 



providing a means of communication between the 

 technical, scientific, and professional workers in the 

 service of the State, and may also serve to iacquaint 

 men of science generally with some of the activities 

 of our numerous Departments of State. 



Messrs. Bowes and Bowes, i Trinity Street, Cam. 

 bridge, have just issued a handy classified catalogue 

 (No. 404) of second-hand books, journals, and mono- 

 graphs dealing with many departments of science. 

 The scope of the catalogue will be seen from the fol- 

 lowing sections into which it is divided : — Journals, 

 Transactions, and Proceedings of Learned Societies; 

 Travels, Exf>editions, etc. ; Biographies of Scientific 

 Men ; General Science, including Evolution, Micro- 

 scopy, etc. ; Biology ; Botany ; Zoology ; Geology, in- 

 cluding Mineralogy; Anthropology, Ethnology, etc.; 

 Chemistry and Physics ; and Portraits of Scientific 

 Men. Upwards of 900 works are listed, and the prices 

 asked are very moderate. The catalogue is' obtain- 

 able upon application. 



Our Astronomical Column. 



K.A. 

 h. m. s. 



Mav 12 6 21 6 



Reid's Comet. — This comet has been readily visible 

 with the naked eye provided its position was known. 

 In the telescope it has been most conspicuous with a 

 large coma, a stump of a tail, and a nucleus which, 

 as Mr. G. Merton expresses it, is planetary rather 

 than stellar in character. It will be nearest to the 

 pole (distance 45°) on May 9. The following is a 

 continuation of the ephemeris from M. Ebell's latest 

 elements. A little sweeping may be necessary to 

 locate the comet (this remark applies also to the 

 comet Pons-Winnecke, which was readily visible with 

 6-in. aperture on April 28, and was glimpsed by Dr. 

 W. H. Steavenson with 2-in.) : 



Ephemeris of Reid's Comet for Greenwich Midnight. 



N. Decl. Log r Log A 



81 36 0-0044 9-9128 



14 7 3 17 77 59 



i6 7 23 48 74 35 o-oo66 9-9636 



18 7 35 47 71 29 



20 7 43 37 68 42 00108 0-0129 



22 7 49 10 66 II 



24 7 53 18 63 55 0-0167 0-0590 



28 7 59 9 60 I 00243 o-ioii 

 June 1839 56 45 0-0333 0-1396 

 5867 54 o 0-0434 0-1745 

 Photographic Catalogue of the Globular Cluster 

 Messier 15. — ^This bright globular cluster is situated 

 near the western edge of Pegasus. Two exposures 

 on it were made with the Bonn astrographic equa- 

 torial (aperture 280 mm.) on 19 16 November 16 and 

 1917 September 24 (exposures 150m. and 90m. respec- 

 tively) by Prof. Kiistner. The positions and proper 

 motions of eight reference stars (re-observed at Bonn 

 by Monnichmeyer) are discussed in Verdff. der Univ. 

 Sternwarte zu' Bonn, No. 15, and a catalogue is de- 

 duced giving magnitudes and rectangular co-ordinates 

 of 1 137 stars in the cluster. Their magnitudes (ex- 

 cluding one star, mag. 807, probably superimposed 

 on the cluster) range from 13 to 16^, their X co- 

 ordinates from -541" to +495", and their Y co- 

 ordinates from -531" fo +509". A similaf research 

 in a few decades will render it possible to pick out 

 the stars optically projected on the cluster. No 



NO. 2688, VOL. 107] 



appreciable change in the positions of the cluster stars 

 can be expected until centuries have elapsed. 



Photographs with a time-interval of forty-four years 

 are now available for the clusters h and x Persei. 

 Measurements of these plates were discussed in a 

 paper by the Rev. H. E. Macklin, S.J., presented 

 to the March meeting of the Royal Astronomical 

 Society. He concluded that the few stars showing 

 displacement in the interval were optically projected 

 on the clusters, and further showed that fifteen of 

 them appeared to belong to the moving cluster in 

 Perseus. 



A Photo-electric Study of Algol.^ — Prof. Joel 

 Stebbins, who in 1909 detected the secondary mini- 

 mum of Algol with his selenium photometer, has 

 recently (Astrophysical Journal, March, 192 1) pub- 

 lished a still more refined research which he has made 

 with the photo-electric cell. He has incidentally 

 detected that 8 Persei is variable to the extent of 

 004 magnitude, and in his later work he used I and 

 n- Persei as his sole comparison stars, Algol's light 

 being reduced by a neutral shade-glass. On the 

 whole, the new research confirms the old very closely, 

 but there is evidence that the components are ellip- 

 soidal, with a flattening of about i in 50. The secon- 

 dary star appears two-thirds as bright with the new- 

 cell as with the selenium one ; it is inferred that it 

 is yellower than the primary, perhaps of spectral type 

 Go. Endeavours have been made to determine the 

 light of the third component, with period of 1-9 years, 

 revealed by the spectroscope, but this has not yet 

 been done with certainty. The greater brightness of 

 the side of the secondary turned towards the primgry 

 is confirmed, though the range is diminished. Taking 

 the light of the whole system as unity, that of the 

 two faces of the secondary is 0-075 and 0045 respec- 

 tively. The values found before were 0-102 and 0058. 

 The area of the bright body obscured at principal 

 minimum is now given as 0-700, and the cosine of 

 the inclination of the orbits as 0-142. It is satisfac- 

 tory to note that the greater precision of the n6w 

 results is accompanied by a reduction in the time of 

 observation. "The new curve represents half the 

 effort of the old one." 



