208 



NA TURE 



[January 2, 1908 



and regional vegetation respectively. The other sheet 

 includes maps of the polar regions on a scale of 

 I : 35,000,000, and three isothermal maps of the world. 



We have received two volumes of the " Agricultural 

 Statistics of India " for the years 1901-2 to 1905-6. The i 

 statistics have been compiled in the office of the Director- 

 General of Commercial Intelligence for the Department of 

 Revenue and Agriculture of the Government of India. 

 The first volume deals with British India, and the second 

 with native States. The total area of India is given as 

 1,133,977,169 acres (1,771,839 square miles), and the total 

 area of the British provinces is 744,907,040 acres 

 (1,163,605 square miles). From a prefatory note to vol. i. 

 the actual area of British India for which statistics are 

 prepared appears to be 557,236,906 acres (870,683 square 

 miles). Less than two-thirds of this area is available for 

 cultivation ; 67,976,325 acres are under forests, and land 

 absolutely barren or unculturable, or covered by buildings, 

 water, and roads, and so on, amounts to 135,329,173 acres. 

 The balance represents the area available for cultivation, 

 of which 207,683,741 acres were actually cropped during 

 the year. Detailed information is supplied in the volumes 

 as to the kind of crops and extent of each, the live-stock, 

 revenue, and transfers of land. Full particulars as to the 

 production of tea and coffee are also supplied. The table 

 dealing with the estimated number of acres on which 

 indigo is cultivated, and the yield in hundredweights, 

 reveals the interesting fact that there was a revival in the 

 indigo industry during 1906-7. The number of acres under 

 cultivation and the yield both show a decided increase over 

 1905-6, and the yield an increase over that of 1904-5, but 

 both sets of numbers still show a great falling off when 

 compared with 1903-4. 



OVR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in January: — 

 Tan. 2-3. Epoch of January meteors (Radiant 230° + 53°). 



3. ih. 51m. to 6h. 42m. Transit of Jupiter's Satellite 



IV. (Callisto). 

 ., Total eclipse of the Sun, invisible in England. 



4. I7h. Neptune in opposition to the Sun. 



5. Sh. 20m. Venus in conjunction with Moon. Venus 

 0° 45' N. 



3h. 32m. to 7h. I4ni. Transit of Jupiter's Satellite III. 

 (Ganymede). 



17. 4h. 19m. to 4h, 34m. Moon occults 5 Geminorum. 

 19 2h. 57m. Jupiter in conjunction with Moon. Tupiter 



1° 33' s. 



,, iih. s6m. Minimum of Algol (/3 Persei). 

 22. 6h. 48m. to loh. 31m. Transit of Jupiter's Satellite III. 



(Ganymede). 

 ,, 8h. 45m. Minimum of Algol (3 Persei). 

 25. 5h. 34m. Minimum of Algol (/3 Persei). 

 2y. 9h. Opposition of Jupiter to the Sun. 

 ,, loh. 4m. to I3h. 46in. Transit of Jupiter's Satellite III. 

 (Ganymede). 



D.\niel's Comet, 1907^. — In No. 4223 of the Astrono- 

 utischc Nachrichtcn (p. 375, December 20, 1907) _ Herr 

 Kritzinger publishes a continuation of his ephemeris for 

 comet 1907J, extending from January 1 to March 5. 

 From this we see that the comet is now apparently 

 travelling, verv slowly and in a direction nearly due east, 

 through the constellation Libra. On January i its posi- 

 tion was o = i4h. 47m., 8= -9° 14', and its computed 

 magnitude was 9-9. On February i the position will be 

 a = i5h. 8m., 8=— 9° o', and its magnitude io-2. Thus, on 

 the latter date, the comet will be very near to the star 

 S Librrc, and during the present month it will rise some 

 five hours befoie sunrise. 



Ephemeris for Encke's Comet. — According to elements 

 published in No. 4222 of the Asironomische Nachrichtcn, 



NO 1992. VOL. 77] 



'5- 



as an abstract from the Bulletin de V Acadimie das Sciences 

 de St. Petershourg, 1907, Encke's comet should arrive at 

 perihelion on February 22. An ephemeris, calculated by 

 M. Kamensky and Frl. Korolikov, is given for the period 

 January 3 to April 30. On the former date the comet's 

 position will be a (app.) = 23h. im. 30s., 5 (app.) 1° 4s'-7; 

 after that it will apparently move in a north-easterly direc- 

 tion through the constellation Pisces in a line nearly 

 parallel to the stars 7, i, and ai Piscium, being very near 

 to I on February 4. 



Absolute Scale of Photographic Magnitudes. — The 

 November (1907) number of the Astrophysical Journal 

 (No. 4, vol. xxvi., p. 244) contains a description of a 

 method devised by Messrs. J. A. Parkhurst and F. C. 

 Jordan for the absolute photographic magnitudes of stars. 

 An ingeniously constructed sensitometer box is employed 

 for illuminating certain areas of a photographic plate 

 simultaneously by lights differing in intensity by a known 

 ratio. Plates thus prepared were measured for the opacity 

 of the different areas by means of a Hartmann " mikro- 

 photometer," which was also used to measure the opacity 

 of the extra-focal star images. A comparison of the results 

 obtained for the Pleiades stars with those published by 

 Schwarzschild proved satisfactory, and indicated that 

 within narrow limits the scale obtained was correct. It 

 also showed that the method is capable of yielding results 

 of extreme accuracy over a range of about two magnitudes 

 on a single plate ; that it should prove useful for deter- 

 mining the light curves of Algol-type and short-period 

 variables is shown by some results given in the paper. 



Annual Astronomical Publications. — The .innuairc 

 for the year 1908, published by the Bureau des Longitudes, 

 is of the usual form, and, in addition to its numerous 

 invaluable astronomical tables, occupying 400 pages, it 

 contains some 360 pages of chemical and phy.sical data. 

 Of the six appendices, dealing with astronomical subjects, 

 we would direct our readers' particular attention to two, 

 the first by M. Bigourdan on " Les Distances des Astres, " 

 the second by M. E. Guyou describing " L E ole d'Astro- 

 nomie pratique de I'Observatoire de Montsouris." 



The Companion to the Observatory is practically of 

 the same form as in previous years. The increase in the 

 number of known variable stars renders it impossible to 

 add all the new ones to the list, year by year, so it has 

 been decided to reduce the number of ephemeridos given, 

 subsequently adding to them if it proves desirable. 

 Complete lists of the Algol variables are given, but only 

 a selected few of the ephemerides. The " inferred " 

 magnetic elements for 1908 (Greenwich) are : — dec, 

 15° 55' W. ; horizontal force, 01854 (C.G.S.) ; dip, 66° 55'. 



Mr. Arthur Mee's card calendar, " The Heavens at a 

 Glance, 1908," is of the usual form, and is an extremely 

 useful publication for astronomical observers. It may be 

 obtained from Mr. Mee, Llanishen, Cardiff, price 71!. 

 post free. 



The Canyon Diablo Meteorites. — Part ii., vol. iv., of 

 the Smithsonian Miscellaneous Collections (p. 203, No. 

 1725) contains an interesting illustrated discussion of the 

 Canvon Diablo meteorites, by Messrs. G. P. Merrill and 

 Wirt Tassin. The former discusses the distribution and 

 physical characters of the " shale balls " found in such 

 large quantities in the vicinity of the canyon in Coconino 

 County, .Arizona. These balls are roughly globular in 

 outline, of all weights up to 50 lb., and consist of an 

 exterior coating of hydrated oxide of iron frequently 

 enclosing unoxidised iron centres, or nuclei, the inter- 

 mediate shell showing a green hydroxide of nickel mingled 

 with oxides of iron. The inspection of a number of these 

 balls and of the ground in which they are found apparently 

 strengthens the theorv of the meteoric origin of the crater. 



Mr. Tassin deals " with the chemical analysis of the 

 "finds," and .shows that these "shale balls" differ to 

 some extent in their chemical composition from the 

 ordinary Canyon Diablo iron. They contain appreciable 

 quantities of chlorine, whereas none has been found in 

 the ordinary "iron," and also contain more phosphorus; 

 to the presence of these two elements the increased oxida- 

 tion of the " shale balls " may be ascribed. 



