May 29, 19 13] 



NATURE 



329 



necessary to dehydrate and reduce the ferric hydroxide 

 to bog ore. 



The English Ceramic Society has recently issued 

 the twelfth volume of its Transactions, and is 

 to be congratulated on the good work which it con- 

 tinues to do in furthering the application of scientific 

 methods to so important an industry. Attention may 

 be directed specially to a paper by Mr. A. J. Campbell 

 in which the application of " surface combustion " to 

 pottery practice is suggested, and to a description by 

 Dr. W. R. Ormandy of an " Electrical Process for the 

 Purification of Clays." This consists in partially 

 coagulating the emulsified clay by the addition of 

 electrolytes, and then further purifying the emulsion 

 by passing it through a vessel containing electrodes 

 differing in potential by 60 to 100 volts. The chief 

 impurities are electropositive, and can thus be re- 

 moved, even when present in very fine particles. The 

 clav-substance is electronegative, and is laid down in 

 the form of a continuous blanket \\ yards wide and 

 \ in. thick. It is deposited in a remarkably dry state 

 with onlv 18 to 20 per cent, of water, and may contain 

 as much as 995 per cent, of china-clay substance. 



Messrs. J. and A. Churchill have nearly ready an 

 English translation of the Italian work, "A Treatise 

 on General and Industrial Organic Chemistry," by 

 Dr. Ettore Molinari. The work of translation has 

 been carried out by Mr. T. H. Pope, of the School of 

 Malting and Brewing of the University of Birming- 

 ham. 



An examination of "The Social Guide, 1913," which 

 has now been issued by Messrs. A. and C. Black, at 

 the price of 2s. 6d. net, shows that the editors regard 

 some scientific meetings at least as social events. 

 Attention is directed, for instance, to the meetings of 

 the Royal Society, the Royal Institution, the Royal 

 Geographical Society, and the British Association. 

 The University Extension meetings arranged in the 

 summer by the Universities of Oxford and Cambridge 

 are also referred to, but, speaking generally, the 

 matters of prominence relate to sports and amuse- 

 ments. The subjects are arranged alphabetically, but 

 an index would assist reference greatly. 

 vp _ p V 



Erratum. — The term .. '* on p. 279 of Nature 



N 



of May 1 5 should have been 



2P-P.M 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences for June : — 

 fune 1. 4I1. 4m. Venus in conjunction with the 

 Moon (Venus 4 38' S.). 

 ,, i2h. o. Mercury in superior conjunction 



with the Sun. 

 4. oh. 25m. Saturn in conjunction with the 

 Moon (Saturn 6° 22' S.). 

 i6h. 4m. Mercury in conjunction with the 

 Moon (Mercury '3 48' S.). 

 7. 4h. 40m. Neptune in conjunction with the 



Moon (Neptune 5 9' S.). 

 19. i4h. 26m. Jupiter in conjunction with the 

 Moon (Jupiter 4 47' N.). 



NO. 2274, VOL. 91] 



June 21. 8h. 8m. Uranus in conjunction with the 

 Moon (Uranus 3 27' N.). 

 ,, 13b.. 9m. Sun enters Sign of Cancer — 

 summer commences. 



22. 6h. om. Vesta in conjunction with the 



Moon (Vesta 0° 31' N.). 



23. 22*h. 35m. Mercury in conjunction with 



Neptune (Mercury 2° 11' N.). 



24. 2I1. om. Venus at greatest distance from 



the Sun. 



29. 5h. 5m. Mars in conjunction with the 



Moon (Mars 4 51' S.). 



30. 7h. 4m. Venus in conjunction with the 



Moon (Venus 7 44' S.). 

 Comet 1913a (Schaumasse). — Astronomische Nacli- 

 richten No. 4652 contains not only numerous observa- 

 tions of the comet which Mr. Schaumasse discovered, 

 but three sets of elements and ephemerides computed 

 by Kiess and Nicolson, Ebell, and Fayet and Schau- 

 masse. The observations made between May 7 and 

 11 give the magnitude between 9-5 and 11. 



The following parabolic elements are those calcu- 

 lated by the last two observers mentioned above, and 

 they are based on Schaumasse's observations at Nice 

 on May 6, 7, and 8 : — 



T = I9I3 May 15-4222 M.T. Paris. 

 » = 53° 32' 8"1 

 43=315 21 7 [1913-0 

 i = 1^2 31 26 J 



log (/ = 0'l62920 



Ephemeris for izh. M.T. Paris. 



1 s 



h. m. s. 



May 30 ... 17 45 55 ... +38 31 

 June 1 ... 17 15 56 ... +40 6 

 „ 3 ... 16 45 33 ... +41 9 

 „ 5 ■■■ 16 15 5° ... +41 35 

 Effective Temperatures of Stars. — An important 

 communication is published in the Comptes rendus of 

 May 5 (vol. clvi., No. 18, p. 1355), by Dr. Charles 

 Nordmann, relative to the effective temperatures' of 

 stars. It will be remembered that Dr. Rosenberg 

 published recently (Astronomische Nachrichten. 

 No. 4628, p. 360) the results of measures of the effec- 

 tive temperatures of seventy stars based on the deter- 

 minations of the intensity of the photographic spectra. 

 It will be remembered also that Dr. Nordmann made 

 a like series of measures based, on the other hand, 

 on visual observations. As the two series of measures 

 deal with different regions of the spectrum they may- 

 be considered as independent determinations, and Dr. 

 Nordmann here compares the results obtained in 

 cases where the same star has been measured. The 

 following table shows the resulting comparison : — 



Effective temperatures 

 (in absolute deerees) 



Nordmann Rosenberg Spectral types 

 AA 460-630 AA 400-500 (Lockyer) 



5 Persei 18500 ... 15500 ... Algolian 



e ,, ... 15200 ... 23000 ... Crucian 



$ ,, (Algol) 13300 ... 12000 ... Algolian 



o Lyrse (Vega) 12200 ... 22000 ... Sirian 



a Persei 8300 ... 6500 ... Polarian 



a Ursa? Minoris (Polaris) ... 8200 ... 5200 ... ,, 



a Canis Minoris (Piocyon) ... 6800 ... 7000 ... Procyonian 



7 Cygni ' ... 5620 ... 5100 ... Polarian 



Sun 5320 ... 4950 ... Arcturian 



a Auriga? (Capella) ... ... 4720 ... 4500 ... ., 



$ Andromeda; 3700 .. 2650 ... Antarian 



a Tauri (Aldebaran) 3500 . 2150 ... Aldebarian 



Dr. Nordmann directs attention to the good agree- 

 ment of the two series, with one or two exceptions, 

 which he discusses, and points out that if the stars he 

 arranged in the order of ascending temperatures thev 

 become hotter and hotter as one passes from the 



