210 



NA TURE 



[June 28, 1906 



physical conditions are the same. The measurements given 

 in the paper show that between the limits ^ = 483/1 and 

 A = 547/t this is very approximately true. 



We have received from Messrs. W. and A. K. Johnston, 

 Ltd., a convenient pad of sectional paper ruled in inches 

 and tenths. The size of the sheets is 8 inches by 10 inches, 

 and the price of the pad is. 6d. net. 



Mr. John Murray has published a fourth edition of Mr. 

 VV. C. Clinton's " Electric Wiring." The first issue of 

 the primer was reviewed in N.mure for October 23, 1902 

 (vol. Ixvi., p. 629). Of the present edition it will suffice 

 to say that in its revision an effort has been made to bring 

 it up to date without increasing its size unduly. 



The current issue of The Central — the magazine of the 

 Old Students' Association of the Central Technical College 

 — commences the third year of publication of what has 

 become an enterprising periodical. Some impressions of 

 South Africa, by Prof. O. Henrici, F.R.S. ; with the 

 British Association in South Africa, by Dr. E. F. Arm- 

 strong; Mr. Freeman's account of the Witwatersrand, and 

 Mr. Ashcroft's description of a lecture-table testing machine 

 are all interesting contributions ; and there are numerous 

 first-rate illustrations. 



A SECOND edition of Dr. W. D'Este Emery's " Hand- 

 book of Bacteriological Diagnosis for Practitioners " has 

 been published by Mr. H. K. Lewis under the new title 

 " Clinical Bacteriology and Haematology for Practitioners." 

 Though the general scope of the book remains unaltered, 

 several additions have been made. The additions to the 

 bacteriological portion are mostly concerned with the ex- 

 amination of materials from special parts of the body. 

 The ha;matological portion is almost all new, and provides 

 a practical guide to blood e.xaminations. especially their 

 application to the diagnosis of disease. The price of the 

 new edition is 7s. 6d. net. 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in July :— 

 July 2. 7h. 55m. to 8h. 52m. Moon occults 7 Libr« 

 (mag. 4-1). 

 ,, I2h. Neptune in conjunction with the Sun. 

 5- I5h. 15m. to i6h. 15m. Moon occults f- Sagittarii 



("lag- 3-5)- 

 6. I2h. 2m. Minimum of Algol (/3 Persei). 



15. 3h. Mercury at greatest elongation (26° 39' E.). 

 ,, Sh. Mars in conjunction with the Sun. 



I3h. 34m. to I4h. 3ini. Moon occults Tauri 

 (mag. 4-3). 

 ,, Venus. Illuminated portion of disc = 076o; of 

 Mars= I '000. 



16. 7h. Ceres in conjunction with Moon. Ceres 



0° 38' S. 

 ,, I4h. lom. to 15h. 2m. Moon occults 7 Tauri 

 (mag. 3-9). 

 17- oh. 40m. Moon approaches near to a Tauri fnia2 

 i-i). ^' 



18. I4h. om. Jupiter in conjunction with Moon. 



Jupuer 3° 2i' N. 



19. Hh. om. to i6h. 40m. Transit of Jupiter's Satellite 



IIL (Ganymede). 

 21. ih. 14m. Partial eclipse of the Sun invisible at 



Greenwich. 

 24. 7h. Venus in conjunction with Moon. Venus 



1° 23' s. 



29. loh. 33m. Minimum of Algol (fl Persei). 



The Figure of the Sun.— In his discussion concerning 



the variable figure of the sun, which was referred to in 



these CO lumns on January 18, Dr. Poor included the helio- 



meter measures of the polar and equatorial diameters 



191 3. VOL. 74] 



made by Messrs. Ambronn and Schur at Gottingen during 

 the period 1890 to 1902, and found from them a confirm- 

 ation of his previous conclusions. 



The validity of the conclusions thus obtained is now 

 questioned by Dr. -Ambronn in No. 4, vol. xxiii., of the 

 Astrophysical Journal. He points out that the variation, 

 if it exists, cannot, according to the heliometer measures, 

 exceed o"i by anv appreciable amount, and suggests that 

 the measurement of the earlier photographic plates could 

 not produce results accurate to this figure. Further, the 

 measurements for 1894 furnish, for the more recent photo- 

 graphs, a proof that the oscillations adduced by Dr. Poor 

 are not present. 



After several other explanations Dr. Ambronn states that 

 the most thorough investigation of the large amount of 

 data collected at Gottingen has convinced him that this 

 furnishes no justification for the suggested periodicity. 



Discovery of Algol V.ariables. — Circular No. 117 from 

 the Harvard College Observatory announces the discovery 

 that the star H1236 (-30°.i6i69 C.DM.) is an Algol 

 variable having a range of about one magnitude and a 

 period slightly exceeding two days. 



This variable was discovered by Mrs. Fleming on a plate 

 taken in accordance with the multiple-image method de- 

 scribed in a previous Circular, and by which it is hoped 

 to discover all the short-period variables of magnitude 100 

 and brighter. In this method a dozen or more exposures, 

 each of thirty minutes' duration, are made on the same 

 plate moved bv a small amount between each exposure. 



Plates covering nearly the whole of the sky have now 

 been obtained under these conditions, but only a few have 

 so far been examined ; nevertheless, this is the second 

 .\]go\ variable thus discovered by Mrs. Fleming. 



An Interesting Minor Planet. — A recently-discovered 

 minor planet (T.G.) proves to be of exceptional interest 

 owing to its great mean distance. 



Elliptical elements recently deduced by Dr. Berberich 

 indicate that the mean distance of this asteroid is slightly 

 greater than that of Jupiter, whilst its aphelion distance 

 is nearly one unit beyond Jupiter's orbit. This discovery 

 extends' the limits of the asteroids so that they now 

 include a distance of 11, the perihelion distance of Eros, 

 and one of 60 units, the aphelion distance of the newly- 

 discovered T.G. (the Observatory, No. 371). 



Observations of Jupiter in 1903 and 1905-6. — In con- 

 tinuation of his record of the observations of Jupiter made 

 during the years 1898-1902 inclusive, which was published 

 in vol. Ixiii. of the Monthly Notices, Mr. Denning now 

 publishes (in vol. Ixvi., No. 7) his results for the opposi- 

 tions of 1903 and 1905-6. 



During 1903. 1388 transits were observed, and of these 

 1 188 were utilised in determining the rotation periods of 

 the different zones as given in the present paper. The 

 periods determined vary from gh. S5m. 54-35. for the N. 

 temperate markings to gh. 50m. 27-95. for the equatorial ; 

 only the latter, however, gives a value less than 

 9h. 55m. 6-os. In the 1905-6 apparition the mean period 

 of rotation of the equatorial spots had increased to 

 9h. 50m. 32-75., a value which is a few seconds in excess 

 of that exhibited during the previous eight years. Mr. 

 Denning also gives a number of notes on the apparition 

 of 1905-6, dealing with the appearance and the variations 

 of the different markings in detail. He also states that 

 the best time for examining details on Jupiter is near the 

 time of sunset. 



The results of a number of micrometer measures of 

 Jupiter's diameter and of the various belts, made at the 

 Copenhagen Observatory during the recent opposition, are 

 published in No. 409S of the .Astronomisclic Nachrichten 

 by Dr. H. E. Lau. 



Photo.metric Observations of Saturn's Satellites. — 

 In No. 4098 of the Astronomische Nachrichten Dr. P. 

 Guthnick publishes the results of a series of photometric 

 observations of Saturn's six brightest satellites. The 

 observations were made during the summer and autumn 

 of 1905 at the Bothkamp Observatory, and the results for 

 Tethys, Dione, Rhea, Titan, and Japetus are set out in 

 tabular form so as to show the anomaly of the satellite- 



