March i, 1906] 



NA TURE 



425 



exi lusively scientific. The meteorological record is as 

 exhaustive as ever, and some reproduced photographs in- 

 cluded in the report show that the photographic section 

 is doing good work. 



The Cambridge University Press has published a third 

 edition of " Hydrodynamics," by Prof. Horace Lamb, 

 F.R.S. The second edition of this standard work was 

 reviewed at length in Nature oi November 21, 1895 (vol. 

 liii., p. 49J. In the present issue no further change has 

 been made in the general plan and arrangement of the first 

 edition, but the work has been carefully revised, occasional 

 passages have been re-written, and many interpolations and 

 additions have been made, amounting in all to about one- 

 fifth of the whole. 



Mr. S. Hikzel, Leipzig, has commenced the publication 

 of a new and elaborate work entitled " Handbuch der 

 anorganischen Chemie," edited by Dr. R. Abegg, assisted 

 by many leading workers in chemistry — particularly 

 physical chemistry — in Germany and elsewhere. The 

 second part of vol. ii. has recently been issued, the title 

 being " Die Elemente der zweiten Gruppe des periodischen 

 Systems." The first part of this volume has not yet 

 appeared, but the first part of the third volume will be 

 published in the spring of this year. We propose to notice 

 the work when the volumes have been completed. 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in March : — 

 March 1. 6h. 14m. to 7I1. 9m. Moon occults f Tauri (mag. 



4-3)- 

 ,, 2. 6h. 41m. to 7h. 45m. Moon occults 7 Tauti (mag. 



3 9)- 

 ,, „ 8h. 5m. Minimum of Algol (B Persei). 

 ,, ,, Ilh. 51m. to I2h. 40m. Moon occults fl 1 Tauri (mag. 



3'9)- 

 ,, ,, I2h. 3m. to I2h. 31m. Moon occults ff 2 Tauri 



mag. 3 '6). 

 ,, II. i6h. um. to i6h. 59m. Moon occults 7 Virginis 



(mag. 3-0). 

 ,, 12. 6h. 21m. to Sh. 31m. Transit of Jupiter's Satellite 



III. (Ganymede). 

 ,, 14. I7h. 22m. to iSh. 23m. Moon occults 7 Libra; 



(mag. 4-1). 

 ,, 15. Venus. Illuminated portion of disc = 0'993 '< °f 



Mars = 0-o,62. 

 ,, 18. 5h. Mercury at greatest elongation (18° 31' E.). 

 ,, ,, ioh. 34m. Transit (ingress) of Jupiter's Satellite III. 



(Ganymede). 

 ,, 19. I2h. 58m. Minimum of Algol (6 Persei). 

 ,, 21. ih. Sun enttrs Aries. Spring commences. 

 ,, 22. gh. 47m. Minimum of Algol ($ Persei). 

 ,, 29. ioh. lupiler in conjunction with Moon (Jupiter 



4° 3 2'N.). 

 ,, ,, 2oh. 5611. to 2lh. 35m. Moon occults a Tauri 



(Aldebaran, mag. 11). 



Comet 1906a (Brooks). — A further extract from Herr 

 M. Ebell's ephemeris for comet 1906a, as published in No. 

 4075 of the Astronomische Nachrichten, is given below : — 



Ephemeris 12I1. M.T. Berlin. 

 ign6 a (true) 6 (true) log r log A Brigbt- 



Mar, 6 ... 5 46 7 ... +60 47 ... 02329 ... 0-0909 ... o 4S 

 8 ... 5 44 18 ... +5S 26 ... o 2376 ... 01072 ... 0-43 

 10 ... 5 43 6 ... +56 15 ... 02423 ... 0-1236 ... 0-39 

 12 ... 5 42 22 ... +54 13 ... 0-2470 ... 0-1398 ... 0-36 

 14 ... 5 42 2 ... +52 20 ... 0-2517 ... 0-1559 ■•• 0'33 

 16 ... 5 41 5S ... +50 35 ... o 2564 ... 0-1718 ... 0-30 

 This comet is now travelling nearly due south towards 



the constellation Auriga, and will apparently pass between 



Capella and B Auriga;, nearer to the latter, on about 



March 21. 



no. 1896. VOL. y 3] 



Comet 1905c (Giacobini). — Count 1905c has now become 

 so faint as to be beyond the reach >>f the naked-eye 

 observer. On March 3 it will be only a little brighter 

 than at the time of discovery, and will set just before 

 9 p.m., or about three hours after sunset, slightly to the 

 south of west. 



An extract from Heir A. Wedemeyer's daily ephemeris, 

 as published in No. 4074 of the Astronomische Nachrichten, 

 is given below : — 



Ephemeris 12I1. M.T. Berlin. 

 1906 a (true) J (true) log r log A Bright- 

 Mar. 2 ... 1 53 41 ... -5 10 ... O0384 ...0-1855 ■• 1 ' 2 ° 

 4 ••■ 2 2 13 ... -4 O ... O0546 ...0-1983 ... 1-05 

 6 ... 2 IO 16 ... -2 54 ... OO7CO ...02109 ... 0-92 

 8 ... 2 17 55 ... - i 51 ... 0-0846 .. 0-2234 ... O Si 



IO ... 2 25 II ... -O 52 ... OO9S6 ...0-2358 ... 0-72 

 12 ... 2 32 6 ... +0 4 ... 0'II20 ... 0-2480 .. 064 

 14 ... 2 38 42 ... +0 58 ... 0-I248 ... 0-2600 ... 0-57 



From this it will be seen that the comet is now apparently 

 traversing the constellation Cetus, and will be about i° due 

 north of the wonderful variable Mira on the evening of 

 March 7. 



A number of full notes of the observation of this comet 

 at the Arcetri Observatory, between December 11 and 31, 

 1905, are given by Signor A. Abetti in No. 4073 of the 

 Astronomische Nachrichten. 



Life op Pietro Tacciiiki. — We have received an interest- 

 ing short biography of Prof. Tacchini, written in Italian 

 by Signor L. Palazzo, who evidently knew the great 

 Italian astronomer intimately, and appreciated his works. 

 The brochure contains nine pages of text and a fine repro- 

 duction of Tacchini 's portrait; it is published by the Typo- 

 graphical Society of Modena. 



Sun-spot Spectra. — A valuable paper on the spectra of 

 sun-spots is published in No. 1, vol. xxiii., of the Astro- 

 physical Journal by Profs. Hale and Adams. The 

 " widened lines " given in the table accompanying the 

 paper number 345, and were measured on ten photographs 

 — including three separate spots — taken with a grating 

 spectrograph in connection with the Snow telescope of the 

 Mount Wilson Solar Observatory. 



The region measured was from A 5000 to A 5853, and, in 

 a second table, the wave-lengths of a number of " bands " 

 shown in the spot spectrum are also given. 



The discussion of the results is extremely interesting, but 

 is too lengthy to be even summarised here. It may be 

 remarked, however, that the lines of titanium showed the 

 greatest mean change of intensity, and that all the silicon 

 lines in the region considered were much weakened. 



Reproductions of some of the photographs obtained 

 accompany the paper, and show the widened lines very 

 clearly. 



" The Heavens at a Glance." — This well known card 

 calendar reaches its tenth year of issue with the present 

 (1906) copy, which contains the usual data and notes. 

 As in former years, we can only remark that it will be 

 found to be a very handy and useful source of reference 

 to everyone engaged in observational astronomy. 



The calendar may be obtained from ils author, Mr. A. 

 Mee, Tremynfa, Llanishen (near Cardiff), for sevenpence, 

 post free. 



THE LANDSLIDE IN THE RHYMNEY 

 VALLE Y. 

 HPHE principal source of the Rhymney River is a copious 

 spring in which the rain-water that has disappeared 

 into numerous swallow-holes, and flowed for some distance 

 underground in the Mountain Limestone, again rise-, to 

 the surface near the edge of the Millstone Grit. From this 

 point the incipient river flows in the direct line of dip of 

 the vtcLta, that is, in a south-south-easterly direction, 

 across the outcrops of the Millstone Grit, the Lower Shale 

 series, and the Pennant Sandstone series of th 

 Wales Coalfield. The length of its course on the Mill- 

 stone (nit is nearly two miles, and on the Lower Shale 

 serii s five miles. 



