256 



NA TURE 



[July 14, 1904 



bo useful in districts remote from medicai aid. Courses of 

 elementary lectures are also given, botli at the college and 

 at the United Service Institution, open to all who mav 

 expect to reside or travel in the tropics. The " Year Book " 

 contains details of the college and its curriculum, and useful 

 directions for the preservation of health in the tropics. 



I.\ the short notice of Mr. Cecil Hawkins's " Elementary 

 Geometry " in N.ature of June 30 (p. 193), reference was 

 made to the absence of numerical answers in the copy 

 supplied. Mr. Hawkins asks us to state that the book is 

 also supplied with answers if desired. 



.Messrs. T. C. .and E. C. J.xck, of Edinburgh, have sub- 

 mitted for our inspection four of the [ilates of a stereoscopic 

 atlas of anatomy, edited by Dr. David Waterston, to be 

 published by them in the autumn. The application 

 of the stereoscopic principle to anatomical illustrations 

 seems, from these examples of it, likely to prove 

 of real assistance to medical and biological students. 

 The plan has already been adopted with success in the 

 teaching of geography and the illustration of books of 

 travel, and there is every likelihood that this further adapt- 

 ation of the stereoscope to educational work will meet with 

 general approval from lecturers on anatomy. Each stereo- 

 graph is accompanied by a brief description written by the 

 editor, and the illustration and description are mounted on 

 one card so as to facilitate reference from one to the other. 

 The series will comprise 250 separate stereographs, and 

 these will be contained in cases. The work will be issued 

 at intervals in sections of about fiftv stereographs. 



OUR ASTRONOMICAL COLUM,\. 

 New Elements and Ephemkris for Comet 1904 a. — 

 In No. 55 of the Lick Observatory Biilletins, Prof. A. O. 

 Leuschner, of the Berkeley .Astronomical Department, gives 

 a set of elements and an ephemeris for comet 1904 <i. cal- 

 culated from observations made by Messrs. .Aitken, Craw- 

 ford, and .Maddrill on April 17, 22, and 29 respectively. 



No. 56 of the same publication contains a second set of 

 elements and an ephemeris calculated by Messrs. Aitken and 

 Maddrill from observations made al Lick on .April 17, 

 May 8, and .May 24. The following are the elements 

 given : — 



T = 1904 MaiLli 6-9049 G.M.T. 



" = 53° 27; i3";8( 



C=275° 46' 5"'5 -Mean iqumox nf 1904 o 



i =125° 7' 33"i) 

 log ^=. 0432475 

 The ephemeris (for oh. G.M.T.) shows that on July 14.5 

 the comet will occupy the following position in the con- 

 stellation Canes Ven. : — True a = i2h. 24m. 28s. True 

 8 = 4- 50° 37' 50", and afterwards will travel very slowly 

 in a southerly direction. As the brightness of the comet 

 is now only 0.37 of its original magnitude, only the larger 

 tele.scopes will be of any use in observing this object. 



The Solar Parali,ax as Determined from the Eros 

 PHOTOCRArns.— At the meeting of the Royal Astronomical 

 Society on June 10, Mr. Hinks gave an" interesting and 

 instructive account of the Cambridge reduction of all the 

 available photographs of Eros obtained during the period 

 November 7-15, 1900. One of the chief features of the paper 

 was a description of the various errors which appeared 

 during the reduction and of the methods employed for their 

 elimination. 



_ The value obtained for the solar parallax in this pre- 

 liminary result was 8".7966 + o".oo47, and this agrees, within 

 the errors of observation, with that previously obtained by 

 Sir David Gill, whilst the probable error is as small as 

 that obtained by him. 



Experiments on the Visibility of Fine Lines. — BiiUelin 

 No. 10 of the Lowell Observatory contains the details and 

 results uf a further series of experiments, performed by 

 NO. 181 I, VOL. 70J 



Messrs. Slipher and I.ampland, on the visibility of tine 

 lines at various distances. The experiments were exactly 

 similar to those previously carried out with a fine wire of 

 0.7 inch diameter, except that a fine blue line 0.7 inch in 

 width, drawn on a white disc 8 feet in diameter, was 

 observed at the same time as the wire. At a distance of 

 1450 feet, when the angular width of the disc was 19' 

 and that of the lines was o".86, the wire was certainly 

 seen, but a fictitious line was seen accompanying what was 

 supposed to be the real one. 



The general results of the experiments indicated that the 

 wire was more generaUy visible than the line, although at 

 distances less than 400 feet the latter was the more readily 

 seen. 



Variability of Minor Planets. — Observations of the 

 magnitudes of the minor planets Iris, Ceres, and Pallas, 

 made by Herr J. Holetschek at Vienna during the years 

 1S99 snd 1903, are published in No. 3955 of the Astrono- 

 mischc Nachrichten. These show that the magnitude of Iris 

 decreased from 7.4 to 7.6 between November i and 

 November 6, 1S99. Observing Ceres in April, 1899, it was 

 found that the magnitude on April gd. I4.5h. was 7.5, 

 on April 13d. iih. 8.1, and on April I4d. 1511. 6.9. 



In the case of Pallas the following magnitudes were 

 observed on the various dates named : — 



1903 M.T. (Vienna) Magnitude 



March 23 ... ... 76 ... S 4 



24 7'6 ... 87 



24 ... 9-8 S-6-87 



25 77 8-4-8-5 



26 7-6 8-5 



A X'ariable Star Chart. — In No. 3^159 of the Astro- 

 nomischc Nachrichten, Prof. Max Wolf publishes 25 charts, 

 each showing the relative position of one of the 25 variables 

 in .Aquila mentioned in earlier communications published by 

 him in the same journal. An accompanying table gives the 

 chart number and the number, the position, the variation, 

 and the designation of the comparison star for each 

 \'ariable. 



The Leeds .Astronomical .Society. — No. 11 of the annual 

 jounial and Transactions of the Leeds Astronomical .Society 

 contains reprints of seven very interesting lectures, on a 

 variety of astronomical subjects, delivered at the society's 

 meetings during last year. .A number of letters on current 

 astronomical questions, contributed to various periodicals by 

 the past president, Mr. C. T. Whitmell, are also reproduced. 

 The frontispiece shows a number of photographic reproduc- 

 tions of ancient coins on which were depicted various 

 astronomical symbols, and illustrates a lecture on that 

 subject delivered by Mr. A. Dodgson. The programme of 

 the meetings for 1904 promises some very interesting 

 papers, whilst the report for 1903 shows the society to be 

 in a thriving condition. 



" .ANNUARIO " OK THE RiO DU JANEIRO OliSERVATORY 



(1904). — The twentieth annual publication if the Rio de 

 Janeiro Observatory contains a large amount of useful 

 information on astronomical, meteorological, and general 

 physical matters. The customary calendars and astro- 

 nomical tables are given in part i. Parts ii., iii., and iv. 

 contain tables of reduction for astronomical and meteor- 

 ological observations. The usual tables for the conversion 

 of foreign standards are given in part v., whilst the sixth 

 and last section contains many useful records of the local 

 meteorological and magnetic conditions for past years, in- 

 cluding the variation of magnetic declination at Rio de 

 Janeiro since 1660. 



GEOLOGICAL SURVEYS OF THE INITED 

 STATES. 



CINCE the appearance of the notice in Nati're of 

 ■^-^ December 3, 1903, the following publications of the 

 United States Geological Survey have been received. 



I. Bulletins. 

 Of very wide interest is the essay on " The Correlation 

 of Geological Faunas : a Contribution to Devonian False- 

 ontology," by Prof. H. Shaler Williams {Bulletin No. 210). 

 The observations are based on a critical examination of the 



