January 5, 1893] 



NATURE 



235 



for bacteriological examination to prevent the multiplication of 

 the micro-organisms present, is really of very little if any use at 

 all. Thus it was already shown several years ago by Percy 

 Frankland that the bacteria in filtered Thames water were able 

 to multiply extensively, even when preserved for some days in 

 a refrigerator. 



The additions to the Zoological Society's Gardens during the 

 past week include a Bittern {Botaurus stellar is), European, pre- 

 sented by Lord Ilchester, F.Z.S. ; two Hamsters {Cricetus 

 frumentarius), British, presented by Miss Pugh ; two Alligators 

 {Alligators mississippiensis), from Florida, presented by Master 

 Williams ; a Common Snipe {Galltnago c(Flestis), British, pur- 

 chased. 



OUR ASTRONOMICAL COLUMN. 

 Comet Holmes (November 6, 1892). — The following is a 

 continuation of Herr Berberich's ephemeris of this comet, the 

 places being for Berlin, midnight : — 



R A. Decl. Log r. Log A. 



0-4119 



0-4143 



0-3400 



0-3516 



The comet is now near to and south following /S Andromedae. 

 Reports from various Observatories state that the comet is now 

 very dim. 



Comet Brooks (November 20, 1892). — This comet is now 

 travelling very quickly. The ephemeris for Berlin, midnight, 

 is continued below : — 



R.A, Decl. Log r. Log A. Br. 

 h. m. s. / 



Jan.] 5 ... 18 29 40 +66 5-4 ... 0*0805 ... 9-8562 ... 7-82 



6 ... 19 o 49 ... 13-6 



7 ... 19 31 22 ... 65 592 



8 ... 20 o 22 ... 24-6 ... o-o8o6 ... 9-8651 ... 7-49 



9 ... 20 27 8 ... 64 324 



10 ... 20 51 19 -f63 26-0 ... o-o8ii ... 9-8781 .. 7-01 



The unit of brightness is taken as that at midnight on 

 November 21. 



The track of the comet lies near the pole of the ecliptic, in 

 the constellation Draco. 



The Spectrum of Comet Holmes. — The spectrum of the 

 comet appears to have bem continuous without any trace of 

 bright bands. At South Kensini»ton it appeared to have its 

 brightest part near the chief carbon fluting (A 517), but there 

 was nothing which could be described as a line or fluting. As 

 might be expected, there was a brighter continuous spectrum 

 from the nucleus. The same result was obtained by Mr. 

 Campbell at the Lick Observatory, and by Prof. Keeler at the 

 Allegheny Observatory. The latter observer remarks that the 

 spectrum is just what we should expect if the comet shines 

 entirely by reflected sunlight. 



The Recent Opposition of Mars. — In the December 

 number of Astronomy, and Astro- Physics, Prof. W. H. Picker- 

 ing summarizes the conclusions derived from the observations of 

 Mars at Arequipa as follows : (i) That the polar caps are clearly 

 distinct in appearance from the cloud formations, and are not to 

 be confounded wiih them. (2) That clouds undoubtedly exi>t 

 upon the planet, diff'ering, however, in some respects from those 

 upon the earth, chiefly as regards their density and whiteness. 

 (3) There are two permanently dark regions upon the planet, 

 which under favourable circumstances appear blue, and are pre- 

 sumably due to water. (4) Certain other portions of the surlace 

 of the planet are undoubtedly subject to gradual changes of 

 colour, not to be explained by clouds. (5) Excepting the two 

 very dark regions referred to above, all of the shaded regions 

 upon the planet have at times a greenish tint. At other times 

 they appear absolutely colourless. Clearly marked green regions 

 are sometimes seen near the poles. (6) Numerous so-called 

 canals exist upon the planet, substantially as drawn by Prof. 

 Schiaparelli. Some of them are only a few miles in breadth. 

 No striking instancesof duplication have been seen at this oppo- 

 sition. (7) Through the shaded regions run certain curved 



NO. I 2 10. VOL. 47] 



branching dark lines. They are too wide for rivers, but may 

 indicate their courses. (8) Scattered over the surface of the 

 planet, chiefly on the side opposite to the two seas, we have 

 found a large number of minute hlack points. They occur almost 

 without exception at the junctions of the canals with one 

 another and with the shaded portions of the planet. 

 They range from thirty to one hundred miles in diameter, and 

 in some cases are smaller than the canals in which they are 

 situated. Over forty of them have been discovered, and for con- 

 venience we have termed them lakes. 



The heights of some of the clouds were found to be not les.s 

 than twenty miles, and indirect observations have led to the 

 conclusion that the density of the atmosphere of the planet is 

 less than that at the surface of the earth, but probably not as 

 much as ten times less. 



Prof. Pickering is of opinion that the opposition of 1894 will 

 be quite as valuable to observers as that of 1892, the distance 

 being but little greater, while the planet will be much farther 

 north, and there is less likelihood of the surface being so much 

 obscured by clouds as during the recent opposition. 



GEOGRAPHICAL NOTES 



An interesting illustration of the rapid development of 

 South Africa is given by the recent appointment of a magis- 

 trate to reside near Lake Ngami to protect the interests of 

 white traders, and enforce the laws restricting the sale of liquor 

 and ammunition to the natives. 



The January number of the Geographical Jottrnal, the new 

 form of the Proceedings of the Royal Geogra^)hical Society, 

 contains a paper and map of some importance by Mr. A. P. 

 Harper, descriptive of the central part of the Southern Alps of 

 New Zealand. Government surveyors have been sent for 

 several seasons to map out the glaciers, and an efi"ort is being 

 made by thoroughly exploring and mapping the region to make 

 it the Switzerland of the southern hemisphere in the estimation 

 of tourists, as it is already by virtue of its fine mountain 

 systems. 



An important paper on the physical conditions of the waters 

 of the English Channel is published by Mr. H. N. Dickson 

 in the new number of the Scottish Geographical Magazine. 

 He shows how the ebb and flow of the tides in the 

 Channel is aff"ecfed by the characteristic form of the main 

 feature of the coast-line, viz. bays with the western side run- 

 ning nearly from south to north, turning at a sharp angle, and 

 lying open to the east. The circulation of the water and its 

 temperature were found to be largely determined by these con- 

 ditions. 



Mr. Coles gave a successful lecture to young people in the 

 hall of the University of London, on Friday last, covering 

 the first half of his subject, " All the World Over," in a very 

 interesting way. Anecdotes of personal adventure combined 

 with exceptionally fine limelight views of scenery to give a vivid 

 impression of the regions touched upon. The second and last 

 juvenile lecture, under the authority of the Royal Geographical 

 Society, will be given on Friday, January 6, at 4 p.m. 



The Royal Scottish Geographical Society announces a course 

 of educational lectures in continuation of those delivered by 

 Prof. J. Geikie and Dr. PL R. Mill last year. The new course 

 will be on the Geographical Distribution of Animals, by Mr. J. 

 Arthur Thomson, who is at present delivering the Thomson 

 Lectures at Aberdeen. The Society has also provided two 

 special lectures to young people, by Prof. C. G. Knott, on 

 Life in Japan, and by Mr. Graham Kerr on his recent travels 

 in South America. 



We understand that a book of travel in Madagascar and 

 Africa, by Mrs. Col vile, F.R.G.S., describing the observations 

 of the authoress on a recent extensive tour, will shortly be pub- 

 lished by Messrs. Blackwood. 



Mr. 1. W. Gregory, assistant in the Geological Department 

 of the British Museum, has joined as naturalist the sporting 

 expedition of Lieutenant Villiers and others, which is on the 

 point of starting up the juba. From Bardera, the head of navi- 

 gation, the party will traverse unknown regions to Lake Rudolf, 

 and from there attempt to cross in a north-easterly direction, 

 through the Galla country and Somaliland to Berbern, on the 

 Gulf of Aden. 



