-4= 



NA TURE 



[November 14, 1907 



by the Daily Mirror for use between London and Paris. 



A demonstration of the methods and results obtained by 



this process was given at the ofifices of that journal on 

 Thursday last, November 7. 



A SECOND edition, revised and enlarged, of Prof. 

 Prafulla Chandra Ray's " History of Hindu Chemistry, 

 from the Earliest Times to the Middle of the Sixteenth 

 Century A.D., with Sanskrit Te.xts, Variants, Translation 

 and Illustrations," has been published by Messrs. Williams 

 and Xorgate. The book appeared first in 1902, and was 

 reviewed in the issue of Nature for May 21, 1903 (vol. 

 Ixviii., p. 5r). Some material additions have been made to 

 the historical portion of the introduction, throwing further 

 light on the independent origin of the Hindu system of 

 medicine and its priority to that of the Greeks. 



The second volume of the French translation of the 

 third English edition of Mr. W. W. Rouse Ball's " History 

 of Mathematics " has been published by M. A. Hermann, 

 of Paris. The price is 8 francs. The translation is the 

 ■work of M. L. Freund. The volume has been edited with 

 additions by Dr. R. de Montessus, while M. G. Darbou.x's 

 paper entitled " Etude sur le D^veloppement des M^thodes 

 g^om^triques, " read at the St. Louis Congress in 1904, is 

 appended. From the same publishers we have received 

 a copy of the second French edition — the work of Mr. J. 

 FitzPatrick— of part iii. of Mr. Rouse Ball's " Mathe- 

 matical Recreations and Essays " ; the translation follows 

 the fourth English edition, and has been enlarged by the 

 inclusion of numerous additions. 



Messrs. George Bell and Sons have published a third 

 edition of " \ Laboratory Outline of General Chemistry," 

 by Prof. Alexander Smith, professor of chemistry in the 

 University of Chicago, which has been revised in collabor- 

 ation with Mr. William J. Hale. The first edition of the 

 book was reviewed in our issue for November 9, 1899 

 <VoI. Ixi., p. 27). In the preface to the present edition, 

 the authors remark :— " In the effort to make misappre- 

 hensions and mistakes as nearly impossible as may be, the 

 directions have been entirely re-written, and in many cases 

 have been amplified, and a number of the experiments have 

 been modified. An entirely new set of figures has also 

 been drawn. To render the exercises more instructive, and 

 ^till further to discourage mechanical work, a larger 

 number of questions has been inserted." 



OUR ASTRONOMICAL COLUMN. 



OcctiLTATiON OF Neptl'xe BY THE MooN. — Dr. Downing 

 directs our attention to an accidental omission from the 

 Nautical Almanac for 1907, of which he publishes par- 

 ticulars in No. 389 (p. 412, November) of the Observatory. 



The data omitted were the particulars of two occult- 

 ations of Neptune by the moon, due to take place on 

 November 23 and December 20 respectively, and visible at 

 Greenwich ; they are as follow : — 



The Improvement of Celestial Photographic Images. 

 — In No. 31 (September 10) of the Lowell Observatory 

 Bulletins, Prof. Lowell describes a method of combining 

 the use of colour screens and isochromatic plates in the 

 photography of Mars, whereby he has succeeded in obtain- 

 ing much sharper images of the planet's details. In the 

 first instance, it was seen that the colour curve for the 

 24-inch object-glass was much flatter in the yellow region, 

 about \ St)0o, than elsewhere, and further that the in- 

 clination of the curve was much greater on the blue than 

 on the red side of the yellow region. To obtain maximum 

 efficiency, then, it seemed necessary to exclude those rays 

 more refrangible than A. 5000, and to bathe the plates so 

 that the orange and red radiations should become more 

 effective. -Accordingly, Mr. Wallace was asked to con- 

 struct screens which would absorb the rays of lower wave- 

 length than \ 5000, and a Seed " 23 " plate, bathed with 

 pinachrome and pinacyanol, was exposed in conjunction 

 with the screen. This, however, was unsuccessful, and 

 Prof. Lowell then tried Cramer instantaneous isochro- 

 matic plates having sharp maxima at \ 4600 and \ 5650. 

 Using the orange screen, which cut out the \ 4600 maxi- 

 mum, very successful photographs were obtained, and 

 Prof. Lowell hopes that during the opposition of Mars in 

 1909 this method will produce much better photographs 

 than those already obtained. He places on record that one 

 of his plates taken at the recent opposition showed a 

 canal which had hitherto escaped detection, but was seen 

 for the first time on examining the planet next night. 



The Great Red Spot on Jupiter. — The acceleration of 

 the Great Red Spot on Jupiter is discussed by Mr. 

 Denning in the Observatory for November (p. 411, No. 

 389), who points out that while the acceleration could be 

 accounted for by the passage of the great S. temperate 

 spot when this occurred, as in 1906, some other explan- 

 ation must be sought for the acceleration during the past 

 summer, when the .S. temperate spot was on the opposite 

 side of the disc to the red spot. Mr. Denning hints at 

 the possibility of there being a minor acceleration when 

 the two objects are in opposition, and indicates the neces- 

 sity for further careful observations. The S. temperate 

 spot has been visible since 1901, and seems likely to 

 continue so for many years ; it was in conjunction with the 

 red spot in May, 1906, and will be so again in .April-May, 

 igoS. 



Red Stars near Nova Velorum. — On examining a plate 

 taken with the 24-inch Bruce telescope on June 6, Mrs. 

 Fleming found the spectrum of a new gaseous nebula, 

 which on further examination proved to be the spectrum 

 of Nova Velorum. This plate includes the region 



R..A. loh. 36m. to iih. 23m., dec — 51° to -57° (1875), 



and shows so many interesting spectra characteristic of 

 red stars that Prof. Pickering publishes a list, in Circular 

 No. 131, giving the C.P.D. designation, the position, the 

 magnitude, and the spectral type of some thirty-four of 

 the included objects. The spectrum of Nova Velorum 

 includes seven bright lines at \\ 5013, 4926, 4862, 4643, 

 4611, 4340, and 4101 respectively, six of which appear to 

 coincide with bright lines in the later spectrum of Nova 

 Persei. The strong helium line at \ 4472, which was 

 bright in Nova Persei (No. 2), is, however, absent from 

 Nova Velorum. 



The Systematic Error of Latitude observed with a 

 Zenith Telescope. — From his observations of latitude at 

 Berlin, Herr Battermann found a systematic difference 

 between the latitudes observed by the east-to-west and the 

 west-to-east positions of the zenith telescope. In No. 4207 

 of the Astronomische Nachrichten (p. 97, October 17) Mr. 

 K. Hirayama, of the Tokyo Observatory, discusses this 

 error, basing his conclusions on the results obtained at 

 various stations, and finds that the difference appears to 

 vary with the zenith-distance. As to how the declination 

 of the observed star can affect the reading of the micro- 

 meter requires further investigation, but Mr. Hirayama 

 suggests that it may be a physiological effect produced 

 by the varying speed of the star in the field. 



NO. 1985, VOL. yyl 



