352 



NATURE 



\Peb. 7, 1889 



A VALUABLE bibliography of Indian geology has been com- 

 piled by Mr. R. D. Oldham, Deputy Superintendent of the 

 Geological Survey of India. It contains a list, as nearly com- 

 plete as possible, of books and papers relating to the geology 

 of British India and adjoining countries, published previous to 

 the end of the year 1887. 



Arnold Guyot's "Earth and Man" has been recently 

 published for the first time in French. The French edition 

 is not a rendering from the English ; it is the original from 

 which the English edition was translated. 



At the monthly meeting of the Royal Institution of Great 

 Britain, on February 4, the special thanks of the members were 

 returned to Mr. William Anderson for his present of a portrait 

 of Prof. Mendelejeff. 



It is reported from North Central Norway and Sweden that 

 wolves are very numerous this winter. They have reappeared 

 in districts where they have been unknown for many years. 



The beaver is getting very scarce in Sweden, but recently a 

 colony has been discovered near the mountain Middagsfjeldet, in 

 the province of Jemtland, in the heart of Sweden. 



It is reported from the districts around the Christiania Fjord 

 that sparrows have almost completely disappeared from those 

 parts this winter. 



Some French students in Paris are distinguishing them- 

 selves by wearing a peculiar cap, the beret of the Pays 

 Basque, to which is joined a small badge, varying in colour 

 according to the Faculty or School (Scientific, Literary, Law, 

 Medical, &c.) the possessor belongs to. The students of 

 Montpellier have been better inspired in reviving the cap 

 worn in the old school at the time of Rabelais. 



We have received the Calendar for the current academical 

 year of the Imperial University of Japan. The record of events 

 for the past year notes that in June the Tokio Observatory was 

 founded. It is formed by the amalgamation of the University 

 Observatory, the Astronomical Section of the Home Depart- 

 ment, and the Astronomical Observatory of the Imperial Navy ; 

 the whole being placed under the control of the University, 

 which is now intrusted with the duty of publishing the Astro- 

 nomical Almanac. By a new arrangement, also, the income of 

 the University from tuition fees and other minor sources is for 

 the present to be accumulated year by year with the object of 

 forming a capital fund for future use. The same is to be done 

 with the fees of other educational institutions under the Educa- 

 tion Department. At the time when the Calendar was issued, 

 276 students were attached to the Faculty of Law, 246 to that of 

 Medicine, 91 to Engineering, 45 to Literature, and 36 to Science. 

 The total number of graduates was 954. 



The additions to the Zoological Society's Gardens during the 

 past week include a Golden Eagle {Aqtiila chrysaetus), European, 

 presented by Mr. Thos. Barclay ; an Alligator {^Alligator mis- 

 sis sippiensis) from Florida, presented by Mrs. G. Peacock ; two 

 Himalayan Monauls {Lophophorus vnfeyanus) from the Hima- 

 layan Mountains, deposited ; an Aard Wolf {Proteles cristaius 

 juv. (J ) from South Africa, purchased. 



OUR ASTRONOMICAL COLUMN. 



The Colours of Variable Stars. — In his new Catalogue 

 of Variable Stars, noticed in Nature, vol. xxxviii. p. 554, Mr. 

 S. C. Chandler gave to each star a number indicative of the depth 

 of the red tinge in its light, and in a more recent paper he has ex- 

 plained how these numbers were obtained. Two independent 

 methods were followed : the first, the one proposed by Klein, and 

 adopted by Schmidt and Duner, in which the stars were ar- 

 ranged according to a scale on which o corresponded to pure 



white light, i to the slightest perceptible admixture of yellow 

 with the white, and so on with 4 for full orange, and lo for the 

 purest red light known to us amongst the stars, and as seen in 

 such examples as R Leporis. In spite of the vagueness of the 

 definition of this scale, Mr. Chandler found by experience that 

 the process of thus referring the impressions of colour to these 

 imaginary standards could be effected with greater precision 

 than he had supposed, or would naturally be inferred by an 

 observer previous to trial. His second method seems, however, 

 to promise more precision, and is both simple and ingenious. It 

 consisted in estimating the relative change in brightness effected in 

 two stars by the interposition first of a blue, and then of a red, 

 shade-glass. Thus, supposing a red and white star appeared of the 

 same brightness when viewed without any shade-glass, the white 

 star would seem decidedly the brighter when the blue glass was 

 used, but the fainter when the red glass was interposed, and 

 these differences could be very precisely estimated by Argelan- 

 der's method, and thus afford definite measures of the differences 

 in colour of the two stars ; of course, on an arbitrary scale 

 depending upon the shade-glasses employed. In all, 665 esti- 

 mates upon 108 telescopic variables were made by the first 

 method, the "decimal scale" method; and 287 "relative 

 diminution estimates," as Mr. Chandler terms his second 

 method, were made upon 77 of the same stars. The mean 

 of the two methods, equal weight being given to each separate 

 observation, was given as the value of the redness of the star 

 in the Catalogue. 



Two somewhat important results appear from these observa- 

 tions : first, that the observations are evidently not affected by 

 any serious systematic error depending on the magnitude, for on 

 the average the same colour is given both at maximum and 

 minimum, the recorded differences being small in amount and of 

 varying sign. It would appear, therefore, that the change in the 

 magnitude of a variable does not usually involve a change in its 

 colour. This is an important point, as the more general opinion 

 hitherto has been that such a change does generally take place. 

 The second result is the intimate connection that exists in a vari- 

 able between length of period and depth of colour. The Algol 

 type stars are strikingly white ; the very short-period stars are 

 colourless, or nearly so ; and those of longer period show a 

 deeper red the greater the duration of their periods. 



New Minor Planets. — A new minor planet. No. 283, was 

 discovered by M. Charlois, of the Nice Observatory, on January 

 28. This is M. Charlois's fourth discovery. 



Comet 1888 e (Barnard, September 2).— The following 

 ephemeris for Berlin midnight is in continuation of that given in 

 Nature for 1888 December 27 (p. 211) : — 



1889. R.A. Decl. Log r. Log ^. Bright- 



h. m. s. , , ness. 



Feb. 9 ... 23 42 28 ... 4 28-0 S. ... 0-2598 ... 0-4096 ... 2-6 



II .. 23 41 51 ... 4 18-5 



13 ... 23 41 18 ... 4 8-9 ... 0-2608 ... 0-4196 ... 2-5 



15 ... 23 40 47 ... 3 59-3 



17 ... 23 40 19 ... 3 49-7 ... 0-2621 ... 0-4284 ... 2-4 



19 - 23 39 54 - 3 401 



21 ... 23 39 31 ... 3 305 .. o 2637 ... 0-4362 ... 2-3 



23 ... 23 39 II ... 3 209 



25 ... 23 38 52 ... 3 11-3 S. ... 0-2656 ... 0-4429 ... 2-2 

 The brightness at discovery is taken as unity. 



Haynald Observatory (Hungary). — The results of the 

 observations of solar prominences at this Observatory during the 

 year 1886 have just been published (Kalocsan, 1888). The 

 observations were made with a telescope of 190 millimetres 

 aperture, and a spectroscope consisting of six flint glass prisms. 

 The chief object was to determine the dimensions of metallic 

 prominences, and their relations to sun-spots. Tables showing 

 all the details of the observations, and the daily and monthly 

 means are given. Prominences less than 20" in height have 

 been neglected. There are also three plates — the first showing 

 the forms of some of the largest prominences observed, and the 

 second indicating the state of the chromosphere for each day of 

 observation between September i and October 31. The third 

 plate, showing the relation of the heights of the prominences to 

 latitude, is particularly interesting. The highest prominences in 

 1886 occurred in latitudes 18° N. and 37° S., whilst there were 

 secondary maxima in 45° N. and 8° S., and tertiary maxima in 

 80° N. and 75° S. The secondary maxima do not fall far below 

 the principal ones, but the tertiary maxima are not nearly so 

 well marked. 



