August 20, 1908] 



NA TURE 



2>77 



Messrs. Burroughs, Wellcome and Co. have issued 

 an interesting and well-produced guide, with descriptive 

 catalogue, of their e.xhibits at the Franco-British Exhibi- 

 tion ; also pamphlets describing their laboratories, and the 

 research work that has been carried out in them. 



The Philippine Journal of Science for April (iii., No. 2) 

 contains a number of important papers relating to medical 

 science— on cholera, on typhus fever, on the virus of cattle 

 plague, and on the venom of the " habu," a venomous 

 snake found in some of the Japanese Islands. 



In No. 33 of the Scientific Memoirs of the Government 

 of India Colonel Bannerman discusses the production of 

 alkali in broth culture media by the plague bacillus, which 

 may reach an amount equivalent to 1-5 per cent, to 2-5 per 

 cent, of normal sodium hydroxide. 



OUR ASTRONOMICAL COLUMN. 



Another Large Sun-spot Group. — The renewal of the 

 sun-spot activity illustrated in these columns last week is 

 being well maintained. On Wednesday, .\ugust 12, the 

 large groups shown on our photograph had reached the 

 western limb of the sun's disc, and on Thursday bad 

 weather prevented observations entirely at South Kensing- 

 ton ; but on Friday morning it was seen that a large 

 scattered group of small spots had broken out near the 

 centre of the disc, whilst numerous small spots w-ere 

 scattered over the surface. This new group was visible 

 to the naked eye, and has apparently evolved from a 

 prominent group of facula; which was observed near the 

 eastern limb earlier in the week. 



The Total Solar Eclipse of December 22-23. — Further 

 particulars concerning the possibility of observing the total 

 eclipse of the sun in the Antarctic, in December next, are 

 contained in a letter we have received from Prof. Wilhelni 

 Krcbs. 



Prof. Krebs points out that both Bouvet Island and the 

 more northerly Thompson Island lie outside the real ice 

 limits, and that only small, isolated icebergs were observed 

 by the expedition ships that have recorded them. Thus, 

 with a totality lasting, according to his calculations, 

 1 1 3 seconds, it might be possible to secure pictures of the 

 corona at Bouvet, or Thompson, Island in December. 

 Meteorological and magnetic observations could be carried 

 out, as also could observations of the shadow bands and of 

 the radiation variations. The approximate times of mid- 

 eclipse in different longitudes are shown below : — 



Longitude 



W. 60° 40° 



h. m. h. 



0° 20° 40° 60° E. 

 h. m. Ii. 111. h. m. h. m. 



G.M.T. Dec. 22-23. ..22 '5 22 37 23 11 23 45 o 15 o 43 16 



One Hundred New Double Stars. — Prof. R. G. 

 Aitken's twelfth list of double stars is published in No. 

 134 of the Lick Observatory Bulletins, and brings the total 

 number now discovered up to 1800. .Ml the double stars 

 in this list were discovered .and measured with the 36-inch 

 refractor, and attention is directed to Nos. 1745, 174H. and 

 1777, which add closer companions to 02 190, 2 1224, 

 and 2 1579 respectively. 



The Night-glows at the Beginning of July. — In No. 

 4266 of the Astrononiische Nachriclitcn (p. 2Q7, August i) 

 Prof. Max Wolf discusses the night-glows which attracted 

 so much attention about July i. On that date Prof. Wolf 

 was unable to carry out his usual programme of photo- 

 graphy because the sky-glare was far too bright, and in 

 the north only such stars as Capella and a and 13 Urs.Te 

 Majoris were e-asily visible to the naked eye. At first Prof. 

 Wolf suspected that a display of aurora was taking place, 

 but failure to observe the aurora spectrum or any fluctua- 

 tions of the light led him to conclude that the phenomenon 

 was due to the peculiar high cirrus cloud that prevailed. 



NO. 2025, VOL. 78] 



August 22 

 .. 31 



h. 

 ■■ 13 

 .. 14 



The Employment of Selenium Cells in Photometry. — 

 Readers of these columns will remember that some time 

 ago Messrs. Stebbins and Brown, of the Illinois University 

 Observatory, made photometric observations of the moon's 

 light, using selenium cells (see Nature, January 16 and 30, 

 pp. 258 and 302), and subsequently showed that the great 

 differences found were due to the different colour-sensibili- 

 ties of these cells (Nature, May 7, p. 18). Referring to 

 these observations in No. i, vol. xxviii., of the Astrophysical 

 Journal (p. 83, July), Prof. Pfund points out that the curves 

 determined by Mr. Stebbins are not true sensibility curves, 

 because the energy curve of the spectrum employed was 

 not taken into account. He also suggests that, at the 

 present time, the use of selenium cells is unwarranted 

 except in observations of the variations of a light source 

 of which the effective area alone changes. A method of 

 employing selenium cells in combination with colour screens 

 for the determination of stellar magnitudes has been devised 

 by Prof. Pfund, and will be fully discussed in a future 

 publication. 



Eclipses of Saturn's Satellites.— During the coming 

 opposition of Saturn, Rhea and the inner satellites will be 

 eclipsed. The following times of eclipse are taken from a 

 paper published by Dr. H. Struve in No. 120 of the Publi- 

 cations of the Astronomical Society of the Pacific : — 



Disappearance Reappearance 



. 4-3 ... 218 ] 14 15 ... 2-1 ... 193 



. 30 ... 211 I 14 59 ... i-S ... 193 



The distances are measured from the planet's limb, and 

 the position-angle from the N. point of the minor axis 

 towards E. (the Observatory, No. 399, p. 326, August). 



A Large Prominence.— In No. i, vol. xxviii., of the 

 Astrophysical Journal (July, p. 79), Mr. Evershed describes 

 a large prominence of which a series of photographs was 

 obtained with the Kodaikanal spectroheliograph on 

 February 18. The first plate was secured at 8h. 23m. 

 (Indian Standard Time), and showed no unusual disturb- 

 ance, but a supplementary photograph at gh. 38m. showed 

 that a prominence faintly showing on the first plate had 

 developed enormously, the disturbed area extending from 

 position-angle 89° to 127°. Visual observations showed 

 prominence matter on Ho, and the sodium and magnesium 

 lines were also observed bright within the affected region. 

 Twenty " limb " spectroheliograms were obtained during 

 the day, the last being taken at i8h. 2m., when the sun 

 was less than 3° above the horizon, and, of these, fourteen 

 are reproduced. These show that the increase in size took 

 place quite gradually, and that the velocity with which 

 the great mass left the sun was, after the first outburst, 

 consistentlv accelerating. The main mass of matter was 

 joined to the sun by a fine filament, situated at the edge 

 of the disturbed area, which appeared to act as a flexible 

 cord holding one end of the mass to the sun and forcing 

 it to swing out in a curve. The greatest height shown 

 on the photographs was 585 seconds of arc, or more than 

 260,000 miles. 



THE WATER OF THE METROPOLIS. 



np HE report of the Water Examination Committee (July 

 ■'■ 18, 1908), and the first report on research work by 

 Dr. Houston, the director of water examinations. Metro- 

 politan Water Board, contain matter of considerable 

 interest. The first details the results of the chemical and 

 bacteriological examinations, many hundred in number, of 

 the raw water and of the filtered supplies delivered to the 

 consumers within the area of the Water Board for the 

 year ending March 31, 1908. The matter is arranged in 

 tabular form, and, inter alia, much information is given 

 respecting the distribution and types of Bacillus coli, the 

 effects of subsidence and filtration on the bacterial content 

 of the water, and the composition of the media ennployed 

 in bacteriological research in the Board's laboratories. 



Dr. Houston's report deals with the important question 

 of the vitalitv of the typhoid bacillus in artificially infected 

 samples of raw Thames, Lee, and New River water, with 



