January 18, 1906] 



NA TURE 



279 



With the title the Australian journal of Science, a new 

 periodical edited by Prof. Liversidge, F.R.S., is to appear 

 during the present month. At first the journal will be 

 issued monthly, but afterwards, if it meets with sufficienl 

 support, at more frequent intervals. Literary correspon- 

 dence, and publications for review, should be addressed to 

 the Editor, Australian Journal of Science, The University, 

 Sydney. 



The thirty-third annual dinner of old students of the 

 Royal School of Mines will be held on Friday, February 16, 

 at the Hotel Cecil. The chair will be taken by Prof. S. 

 Herbert Cox; and the opportunity afforded by the dinner 

 will be taken to make a presentation to Prof. J. YV. Judd 

 on his retirement from the chair of geology. Subscriptions 

 for this testimonial should be forwarded before the end of 

 January to Mr. D. A. Louis, 77 Shirland Gardens, \\\, to 

 whom applications for tickets for the dinner should also 

 be sent. 



The publication by Mr. George A. Morton, of Edin- 

 burgh, at 3.5. (vl., of an attractive edition of Hugh Miller's 

 " My Schools and Schoolmasters " should serve to re-direct 

 attention to the work of a geologist whose writings were 

 in the middle of last century the means of attracting many 

 persons to the study of natural phenomena. A biographical 

 introduction to the volume by Mr. W. M. MacKenzie 

 provides an interesting study of Hugh Miller's career as 

 stonemason, bank clerk, editor, geologist, and author, and 

 reminds the reader that this work of his was published in 

 1S54. The stonemason who by his own unaided efforts 

 could attain to such an acquaintance with the rocks of his 

 native land as to become the author of " The Old Red 

 Sandstone " should prove an encouragement to all students 

 of science who are working in the face of great difficulties. 

 This new re-issue deserves a wide popularity. 



A booklet by Mr. J. El. David entitled " Le Tunnel du 

 Simplon " has been published by Messrs. Payot and Co., 

 of Lausanne. Parts of the account have already appeared 

 as articles in the Gazette de Lausanne. In view of an 

 article which appeared in Nature of November 9, 1905, 

 p. 30, describing survey work of the Simplon Tunnel, it is 

 unnecessary to do more than refer to the contents of the 

 brochure. Before publication the text was submitted to 

 the chief engineers in charge of the work, so that the book 

 may be read with confidence as containing a correct 

 account of the order of events. The biographical notices 

 and portraits of the engineers in charge of the gigantic 

 undertaking, and other numerous illustrations, add greatly 

 to the value of this essay. 



OUR ASTRONOMICAL COLUMN. 



1 omet 1905c (Giacobini). — A new set of elements and 

 an ephemeris for comet 1905c appear in No. 88 of the 

 Lick Observatory Bulletins ; they have been computed by 

 Mr. R. T. Crawford, of the Berkeley astronomical depart- 

 ment, and the elements are as follows : — 



T=i9o6 Jan. 22-41845 G.M.T. 



00 = 199 1 28-8") 



& = 92 2 oo'5 j-igo6'0 



i = 43 38 367 J 



log q = o '2 1 7605 



The ephemeris shows that after perihelion (January 22) 

 the comet's brightness will decrease rapidly, falling from 

 586 on that date to 22-7 on January 30. The positions 

 (true) are given for alternate days during January, but only 

 the three given below have been computed for dates sub- 

 sequent to January 2S : — 



Ephemeris oh. G.M.T. 

 « (true) S (tr 



Brighine 



227 



i-5 



Jan. 30-5 ... 21 53 28 ... - 25 44 25 

 Mar. 1-5 ... 1 48 II ... - 6 2 44 

 April 2-5 ... 3 29 3 .. +79 5° ■• °'3 



Numerous observations of this comet are recorded in 

 No. 4065 of the Astronomische Nachrichten. Dr. Jost, 

 observing at Strassburg on December 30, 1905, found that 

 the magnitude was about 5-0, and that the comet had a 

 sharp definite nucleus and a tail about |° in length. On 

 January 1 the magnitude was 40-5-0, the diameter of 

 the nucleus 4", and the length of the tail about ii°. 



A daily ephemeris, extending from January 13 to 

 January 31, is given by Herr E. Strdmgren in the same 

 journal. 



Nebulosity around Nova Aquil/E.— Prof. Frost re- 

 ports that a careful examination of the photographs of 

 Nova AquilfE No. 2, taken with the Bruce telescope at 

 Arequipa on October 16 and 21, 1905, shows the Nova to 

 be surrounded with a faint nebulosity nearly circular in 

 form and extending to about o'-4 on each side of the star. 

 The exposure in "each case was 120 minutes, and the 

 nebulosity was independently confirmed by Mr. Manson. 



As no 'such nebulosity appeared on the engraving given 

 in vol. xxii. (p. 269) of the Astrophysical Journal, re- 

 presenting the Nova on September 21, 1905, Prof. E. C. 

 Pickering suggests that it radiated from the Nova early 

 in October, as was the case in Nova Persei No. 2. lie 

 points out, however, that, if it can be shown that the 

 spectrum is peculiar, the apparent nebulosity on the Bruce 

 photographs may be explained as being due to chromatic 

 aberration which does not exist in the reflector, and would 

 therefore not affect the earlier photograph I Ystronomische 

 Nachrichten, No. 4065). 



The Figure of the Sun.— Continuing his research on 

 the variable figure of the sun, Dr. C. L. Poor has reduced 

 the values of the solar diameter obtained by Schur and 

 Ambronn, with the 6-inch Repsold heliometer of the 

 Gottingen Observatory, during the thirteen years 1890 to 

 1902. 



A detailed description of the methods of reduction is 

 given in No. 5, vol. xxii., if the Astrophysical Journal, and 

 the results tend to confirm those obtained in Dr. Poor's 

 previous research, viz. that the ratio between the polar and 

 equatorial radii of the sun varies periodically, the period 

 being nearly the same as that of sun-spots. The ampli- 

 tude of the" variation is about o"-2, the greatest difference 

 between the extreme values of the quantity (polar - 

 equatorial diameter) being o"-5- 



Stellar Magnitude of the Sun.— The results of an 

 interesting research made by Prof. Ceraski at Moscow on 

 the relative magnitudes of the sun and Polaris, Procyon, 

 and Sirius, are given in No. 4065 of the Astronomische 

 Nachrichten. During the day Prof. Ceraski photo- 

 metrically compared the light received from Venus With 

 that obtained from a reflected image of the sun, and then 

 at night compared Venus with the stars named. 



As a result he found that the sun sends us 290550x10 s 

 times more light than Polaris, 77630X10° times more light 

 than Procyon, and 17045X10" more than Sirius. Taking 

 the magnitudes of lliese stars as 215, 0-56, and —109 

 respectively, this gives -26-51, -2666, and -26-67 as ,hp 

 stellar magnitude of the sun' and the weighted mean value 

 becomes -26-59. As Prof. Ceraski objects to the obvious 

 paradox in assigning a negative value to the sun's magni- 

 tude, he omits the" minus sign and gives his result as 

 "26-50 super magnitude." 



Variability of Iris.— The results of a number of photo- 

 metric measuremenls of the apparent brightness of Ins. 

 carried out by Dr. H. Clemens during February and 

 March, 1904, are given in No. 4063 of the [stronomischi 

 Nachrichten. 



The lowest magnitude was recorded at ioh. 15m. 

 (M.E.T.) on March 28, and was 10-34; the highesl maxi- 

 mum observed (S-So) took place on February at 8h. 46m. 

 From the consideration of his results, Dr. Clemens con- 

 cludes that Iris has a real variation of magnitude amount- 

 ing to 0-25111.-0 30m., and having a period of approximately 

 four hours. 



NO. 189O, VOL. 73] 



