January 26, 191 1] 



NATURE 



417 



appeared, as the causes which have led to the extinction 

 are probably still active. Whether the continental Bacillus 

 salmonicida is identical with the British B. salmonis pestis, 

 Patterson, is not stated in the article. 



The annual volume for igio of the Bulletin of Miscel- 

 laneous Information, issued from the Royal Botanic 

 Gardens, Kew, has now been published at the price of 

 45. 6d. Attention has been directed already in these 

 columns to the papers in separate numbers of the Bulletin, 

 and it is sufficient to say here that the volume contains 

 ten numbers, four appendices, and a complete index. 



A LIST of Siamese plants compiled by Dr. C. C. 

 Hosseus, and published in the Beihefte zuni Botanischen 

 Centralblatt (vol. xxvii., part ii.), represents, as the 

 author points out, merely a contribution to the flora of 

 Siam, inasmuch as some of the provinces are entirely un- 

 explored. The author has received valuable help from 

 nany botanists in the identification of his specimens, and 

 as furnished indications of the regions from which each 

 species was obtained. The list shows a preponderance of 

 Leguminosae and Cyperaceae. 



The latest part (vol. iv., No. 4) of the Records of the 

 Botanical Survey of India is devoted to the notes con- 

 tributed by Mr. I. K. Burkill with reference to a journey 

 nto Nepal. The author collected few novelties — three 

 species of Impatiens and an Eriocaulon — which is explic- 

 l able, as he traversed nearly the same route at the same 

 =oason of the year that Wallich took eighty-seven 3'ears 

 irlier. The notes relate chiefly to detailed features of the 

 getation and a comparison of the sdl, Shorea robusta, 

 jrests and flora of the hill tops in Nepal with those in 

 Sikkim. 



Mr. .\skin Nicholas, writing from 31 Queen Street, 



Melbourne, advances a curious explanation of Glacial 



periods of geology. He suggests that " the Glacial period 



corresponds with the period in which the moon lost its 



water. To me it seems feasible that this would be 



annexed by our planet by first forming a ring around 



it, under which ring would be a perpetual shadow of 



great width." But Mr. Nicholas's suggestion would not 



explain either the geographical distribution of areas of 



heavy glaciation or the recurrence of such glaciations. 



^ Mr. Nicholas refers in the course of his letter to the 



facial periods, and thus recognises that there have been 



lore than one ; and the last was geologically so recent 



liat it would seem most improbable that there should 



>.ave been any important change in the condition of the 



moon since that date. If the suggestion were valid, the 



noon should also have lost its water once during pre- 



ambrian, in Cambrian, and Carboniferous times. Mr. 



Nicholas will find a discussion of the supposed causes of 



glaciation in Chamberlin and Salisbury's " Geology," 



vol. iii., 1906, pp. 424-46. 



La Nature for December 17, 19 10, contains a photograph 

 of the " Spectre of the Brocken," taken some time ago bv 

 M. Th. Moureaux on the terrace of the observatory of the 

 Pic du Midi. It shows in the centre of the corona the 

 hadow of the operator holding up the photographic 

 apparatus. On the summit of the peak and to the west- 

 ward patches of cumulus cloud were scattered over the 

 ky, and at times the sun shone out brightly on the rising 

 .ists. The author of the note (M. J. Loisel) states that, 

 -0 far as he knows, this is the first time that the spectre 

 as been photographed. He refers to M. Lancaster's 

 xperience at Uccle at the time of a thick fog in July, 

 1892, during which he saw his shadow projected by a lamp 



te^ NO. 2152, VOL. 85] 



burning in a room on the second floor, and all his move- 

 ments reproduced. M. Loisel remarks that it would be 

 interesting to observe whether the phenomenon would be 

 repeated in any thick fog, or only under special conditions. 



We have received a catalogue of physical apparatus and 

 optical goods from Messrs. R. and J. Beck, which con- 

 tains a longer list of parts of optical apparatus, e.g. 

 lenses and prisms of glass or quartz, than we have seen 

 previously in any English catalogue. It will prove of 

 great help to those who are constructing apparatus for 

 special purposes. The most noteworthy larger pieces of 

 apparatus described are a lens-testing bench with all the 

 fittings requisite for the rapid examination of spectacle 

 lenses, and a large optic bench for interference and diffrac- 

 tion observations, which Messrs. Beck have made into a 

 universal instrument by providing it with a spectrometer 

 to fit on to one of the upright pillars, and with the lenses- 

 and polarising prisms necessary for the c^ticai examination 

 of crystals. 



A COPY of the " Instructions of the Metropolitan Gas 

 Referees " for the year 1911 has reached us. These 

 instructions are practically identical with those issued last 

 )'ear, the only change being that the 10 cubic feet of gas 

 burnt for the determination of the total sulphur is allowed 

 to be burnt at a somewhat faster rate — 0-62 foot per hour 

 instead of 05. In the determination of the calorific value 

 of the gas. the calorie used is now specially defined as 

 " the amount of heat which will raise the temperature of 

 a litre of water one degree centigrade," the temperature 

 at which the water is measured not being stated. 



Messrs. D. AprLETOX and Co. will publish shortly a; 

 new work of travel entitled "The Big Game of Africa," 

 by Mr. R. Tjader, who has studied very closely the 

 characteristics of the big game which he has hunted, and 

 paid attention to the scientific side of the subject. 



OUR ASTROXOMICAL COLUMN. 



Meteors is February. — Mr. \V. F. Denning writes : — 

 " February is not a specially interesting one as regards- 

 meteors, but it has presented many brilliant fireballs in' 

 past years, and indications of several showers of some- 

 what important and active character. 



" The writer has never made ver}' extensive observa- 

 tions in this month, but from the data he has secured 

 and from tlie paths of meteors observed by other persons 

 he has long regarded a shower of Aurigids as the most 

 prominent and richest stream of the period. The radiant 

 is about at 75° + 42°, and the time of visibility apparently 

 extends from Februarj- 5 to 23, but this is uncertain. The 

 meteors are slow and often bright. 



" Observers would do useful work by watching the sky 

 on clear February nights, when moonlight does nott 

 materially interfere. They might secure useful evidence 

 as to the Aurigid shower, and would probably notice a 

 few of the fireballs which commonly appear at this time 

 of the year. The most remarkable fireball of modem 

 times appeared on February 22, 1909. 



" This year the moon will not interfere in the evening 

 of February 22, and the paths of such meteors as are 

 seen should be carefully registered and other details 

 noted." 



Nova Lacertje. — Observations of Nova Lacertje, made 

 at Bergedorf on January 2, are reported by Dr. Graff in 

 No. 4465 of the Astronomische Nachrichten. Two sets of 

 comparisons with neighbouring B.D. stars gave, for the 

 magnitude of the nova, 6-8, and its rose colour is com- 

 pared with that of Nova Persei in May, iqoi, being about 

 5-5° on Schmidt's scale of colour. Visual spectrum 

 observations gave C and F, probably, and brightenings in 

 the yellow and violet ; strong absorptions in the orange 

 and on the other side of F were also noted. 



