May 2, 1907] 



NATURE 



17 



in the opposite direction, a phenomenon which, under the 

 conditions of Mr. Svvinton's experiments — very low pressure 

 and discontinuous current — is actually reversed. 



Reference was made in Nature of April 4 (p. 543) to 

 a paper by Mr. C. E. Moss on the " Geographical Distri- 

 bution of Vegetation in Somerset." The paper is pub- 

 lished by the Royal Geographical .Society, but did not 

 appear in the Geographical Journal. 



A CORRESPONDENT asks for a reference to the latest 

 discussion of the stadium of Eratosthenes and the official 

 or Royal Egyptian stadium mentioned in a recent review 

 in Nature (.April 11, p. 553). The information required 

 will be found in " Griechische und romische Metro- 

 logie, " by F. Hultsch (Berlin, 1882), and in Dr. Dreyer's 

 " History of the Planetary System " (Cambridge, 1906). 



A SECOND edition of " The Textile Fibres : their 

 Physical, Microscopical, and Chemical Properties," by Dr. 

 J. Merritt Matthews, of the Philadelphia Textile School, 

 has been published by Messrs. John Wiley and Sons, of 

 New York, and Messrs. Chapman and Hall, Ltd., in this 

 country. The book has been re-written, and is intended 

 to bring together all the material available for the study 

 of the textile fibres. The price of the volume is 17s. net. 



Messrs. Witherbv and Co. announce the forthcoming 

 publication of a limited edition of a work on " The 

 Vertebrate Fauna of North Wales," by Mr. H. E. Forrest. 

 The work will be a history of the mammals, birds, 

 reptiles, amphibians, and fishes to be found in that part 

 of Wales lying north of the Dovey Estuary, illustrated 

 with plates depicting notable haunts of typical species, 

 portraits of Pennant and other former recorders, and a 

 coloured map of the district. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in May : — 

 May I. Ilh. Mars in conjunction with Uranus, Mars 0° 46' S. 

 ,, Mars. Apparent diameter = I2"'54. 

 1-6. Epoch of Aquarid meteors. Radiant 337°- 2°. 

 6. loh. 31m. Minimum of Algol (/3 Persei). 

 16. 7h. 13m. to loh. 27m. Transit of Jupiter's Sat. HI. 



(Ganymede). 

 21. I2h. Jupiter in conjunction with Neptune. Jupiter 



1° N. 

 26. I2h. 14m. Minimum of Algol (18 Persei). 

 ,, i6h. 6ni. to i6h. 52ni. Moon occults 9 Librte (mag. 

 4-3)- 

 Comet 19076 (Mellisii). — An extension of the ephemeris 

 given by Miss Lamson and Frederick, computed by Dr. 

 Stromgren, appears in No. 4172 (April 20) of the Astrono- 

 inische Nachrichten, and gives the calculated daily posi- 

 tions of the comet up to May 10. This object is now 

 barely one-tenth as bright as when discovered, and, 

 according to the elements, was nearest to the earth on 

 April 10-98. 



The Ring of Minor Planets. — Some very interesting 

 facts are educed in a discussion, by Dr. P. Stroobant, 

 which appears as an extract from the Aiinales d'Observ- 

 atoire Royal de Belgique, vol. ix., part iii. ; Dr. 

 Stroobant's subject is the constitution of the ring of minor 

 planets, and he considers the relative distribution, the 

 masses, and the classification of the first 512 of these 

 bodies. After giving a very abbreviated history of the 

 discovery and study of asteroids, the paper discusses the 

 lacunae in the grouping of the minor planets, and also 

 the grouping in regard to their mean distances from the 

 sun. A decided maximum occurs between the limits 

 marked out by rings respectively 2-55 and 285 astro- 



NO. 1957, VOL. 76] 



nomical units from the sun, 199 of the asteroids considered 

 revolving in this annulus. 



From a discussion of the available data concerning the 

 magnitudes and probable diameters of asteroids, it is 

 found that nearly all the asteroidal matter is concentrated 

 near to the middle of the ring in the neighbourhood of the 

 mean solar distance of 27, whilst further analysis shows 

 that, as a general law, the smaller asteroids are relatively 

 less numerous in the richest zones. .\t the end of the 

 paper Dr. Stroobant tabulates the 512 asteroids in order 

 of their mean distances from the sun, and gives the mean 

 movement, the mean distance, and other data for each. 



Positions of Piicebe, 1898-1904.— No. 3, vol. Ix. (pp. 

 45-5*5). of the Harvard College Observatory Annals con- 

 tains the measured positions of Phoebe, the ninth satellite 

 of Saturn, during the period 1898-1904. 



The places of the standard stars employed were taken 

 from the C.P.D. for the epoch 1875-0, and, should greater 

 accuracy be required, all the material for a second reduc- 

 tion is included in the present memoir ; it will only be 

 necessary for such a reduction to determine the places 

 of the standard stars with greater accuracy. 



Observations of Thirty-three Variable Stars.— In 

 Bulletin No. iio of the Laws Observatory, University of 

 Missouri, are published the preliminary results obtained 

 from the observations of thirty-three variable stars, the 

 light-curves and periods of which are as yet imperfectly 

 known. The bulletin gives a list of the stars considered, 

 with their places for 1855-0, followed by a brief discussion 

 of the results yet obtained for each star. These results 

 are compared with previously published elements, and in 

 some ca.ses the light-curves are reproduced. 



The Italian Prominence Observ.\tions, 1877-1883. 



No. 5, vol. xxxvi. (p. 54, 1907), of the Memorie della 

 Societd degli Spettroscopisti Italiani contains a series of 

 notes on the prominence observations made at Palermo 

 and Rome from 1877 to 1883. These notes give the atmo- 

 spheric conditions for each observing day, and brief re- 

 marks on any observation of especial interest, and should 

 prove useful in any discussion of these valuable observ- 

 ations. 



The Spectrum of Mira. — A brief discussion of the spec- 

 trum of Mira, photographed at the Lowell Observatory 

 on January 11, is published by Mr. V. M. Slipher in 

 No. 3, vol. XXV. (p. 235, April), of the Astrophysical 

 Journal. The region shown on the plate includes Ho, 

 H/3, Hy, and H5, all of which are bright and increase 

 in intensity in the order given. The series of absorption 

 bands commences at X 4584, possibly at \ 4463. and 

 appears to extend beyond the region photographed, i.e. 

 beyond K 7000. Vanadium absorption is strongly repre- 

 sented. A comparison of this spectrum with that obtained 

 by Stebbins, at Lick, in 1902, shows that H/3 (and prob- 

 ably Ha) was more intense during the more recent maxi- 

 mum. On the other hand, the series of dark bands 

 appears to have been more intense, and to have extended 

 further into the ultra-violet, in 1902. 



The Harvard College Observatory. — Prof. E. C. 

 Pickering's report of the work done at the Harvard 

 College Observatory during the year ending September 30, 

 1906, sounds a note of disappointment at the lack of 

 financial support given to the schemes for astronomical 

 work on well organised lines which he has formulated. 

 The amount of meridian and photometric work accom- 

 plished was on the usual immense scale, and it is hoped 

 that when the 60-inch Common telescope is completed the 

 visual work will be greatly extended to the faintest stars. 



On the Henry Draper memorial photographs Miss 

 Cannon studied 691 stellar spectra and classified them. 

 Three stars, H.P. 934, H.P. 3030 and 4-44°. 3639, were 

 found to show the second series of hydrogen lines. Mrs. 

 Fleming also found numerous variable stars and stars 

 having peculiar spectra on plates taken with the 8-inch 

 Draper, the S-inch Bache, and the 24-inch Bruce tele- 

 scopes respectively. A great amount of work was also 

 performed at the .Arequipa station and at the Blue Hill 

 Meteorological Observatory. 



