MO 



NA TURE 



[July 4, 1901 



widely distributed, having been found in aqueous extracts of 

 spleen, pancreas, liver, kidney, brain, muscles and blood serum. 

 Infusoria, insects, worms and molluscs were also examined, with 

 positive results. 



The additions to the Zoological Society's Gardens during the 

 past week include two North African Jackals [Canis anthus) 

 from Algeria, presented by Mr. G. E. Hope ; a Rhesus Monkey 

 (Macaciis rhesus) from India, presented by Mrs. Mould ; a Suri- 

 cate {Siirkata tetradactyla) from South Africa, presented by 

 Captain R. Feilden ; a Leopard {Feli'i pardiis) from Africa, 

 presented by Captain G. Burrows ; two Stanley Cranes 

 (Aiithrepoides paradisea) from South Africa, presented by 

 Mr. A. W. Guthrie ; a Yellow-cheeked Amazon (Chiysotis 

 aiittininalis) from Honduras, presented by Mrs. Bullock ; a 

 Rough-legged Buzzard (Archibnteo lagopus) from Norway, pre- 

 sented by Dr. E. A. Williams ; a Leopard Tortoise ( Testudo 

 pardalis) from South Africa, presented by Major J. Day ; five 

 Leith's Tortoises ( Testudo leithi), eight Basilisk Chameleons 

 {CItaiiiaekon basiliscus), two Common Q,\aemA^ans(Chamaeleon 

 vulgaris), three Schneider's Skinks (Enmeces schneideri) from 

 Egypt, presented by Mr. Stanley S. Flower ; a Spix's Macaw 

 [Cyanopsittacus spixi) from North Brazil, two Barbary Wild 

 Sheep {0-ois tragelaphiis) from North Africa, a West African 

 Python {Python scbae) from West Africa, fourteen North 

 American Trionyx (Trionyx fero.x), six Lesueur's Terrapins 

 (Malacoilemmys lesueuri) from North America, seven Roofed 

 Terrapins {Kachuga leetumi) from India, two South American 

 Rat Snakes (Spilotes pullatus) from South America, three 

 Cunningham's Skinks {Egernia cunninghami) from Australia, 

 two Wallace's Lories {Eos laallacei) from Waigiou, a New 

 Zealand Parrakeet {Cyanorhamphus novae-zealandiae) from 

 New Zealand, deposited ; two Spoonbills (Platalea leiicorodia), 

 European, purchased ; a Burrhel Wild Sheep ( Ovis burrhel), a 

 Squirrel-like Phalanger {Petaurus seiureus), two White Ibises 

 {Eudocimus albus), bred in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Spectrum of Nova Persei. — In the current issue of 

 Comptes retidus (vol. cxxxii. pp. 1542-1544) M. Deslandres 

 gives a third series of observations of the spectrum of Nova 

 Persei as obtained at the Meudon Observatory. Since the 

 previous communication, spectrographs of varying power have 

 been installed for use with the two telescopes of 0*84 metre and 

 060 metre aperture, and both photographic and visual records 

 of the spectrum obtained during the periods of minima, although 

 unfavourable weather has considerably interfered with their 

 continuity. In this later work special attention has been 

 devoted to the expected detection of the principal nebular lines. 

 M. Deslandres states that during the first stages the principal 

 green lines present were distinctly not the nebular lines, but the 

 lines of parhelium, A492 and A5015, this being well shown in a 

 photograph taken on March 3. On a plate taken on April 17, 

 however, the measured position of the chief green line was 

 ^5008, but on account of breadth of line the value is of course 

 only approximate. The star was near its minimum brightness 

 on this date. The gradual varying intensity of this line relative 

 to the H^ line of hydrogen is then described, the details being 

 in close agreement with those already published by other 

 observers. 



On May 14 a fainter line was seen near the next nebular line, 

 about A495g, '^^ star being less than 7th magnitude, and he 

 concludes that at that tmie the spectrum of the Nova was com- 

 pletely nebular, also mentioning that M. de Gothard had 

 detected the ultra-violet nebular line A.386 in the spectrum of 

 the star. 



Dark Spot on Jupiter. — In ihe Astronomische Nachriehlen 

 (No. 3724) Mr. T. E. R. Phillips gives the results of several 

 observations by others and himself extending from March 2 to 

 June 2. 



The spot as seen by these observers is in the white north 



NO. 1653, VOL. 64] 



tropical zone, in about latitude -I- 15". At present it appears to 

 be quite detached from the northern edge of the north equatorial 

 belt, but when first seen gave the impression of being merely a 

 dark projection from that belt into the north tropical zone. 

 Possibly the reason for the present appearance is the apparent 

 narrowing of the belt which has been observed for some time 

 past. 



A table is given showing the results of nine determinations, 

 the discussion of which indicates a period of gh. 5Sm. 297s. 



THE METEORIC EPOCH OF JULY 



AND AUGUST. 



1\/T ETEORS are generally rare in the early part of the year, 

 •'■'•'■ and, in May and June, twilight is so strong that it 

 obliterates faint objects and leaves only the more conspicuous 

 class of meteors observable. But in July, though the sky is 

 still very light and the nights extremely short, these objects 

 become fairly plentiful and particularly so during the last week 

 of the month, when the horary rate of apparition is about three 

 times as great as it is on ordinary nights of spring and mid- 

 summer. The meteoric observer regards July and August not 

 only as one of the most productive seasons of work, but one 

 which in the interesting character of its results will compare 

 favourably with that of any other epoch of the year. 



There is a rich shower of Aquarids annually visible on about 

 July 27-31, and apart from this stream the great system of 

 Perseids, which has rendered the month of August so famous in 

 meteoric annals, has actively commenced and supplies no incon- 

 siderable proportion of the shooting stars visible at the close of 

 July. Other showers are plentifully distributed over the firma- 

 ment, but the majority are very feeble and may only be distin- 

 guished by close and prolonged watching during several clear 

 nights. 



The writer recently undertook the rediscussion of about 260 

 meteors which he has recorded from the shower of Aquarids, 

 in various years, with a view to discover whether there were 

 any indications of motion in the radiant. Grouping the obser- 

 vations into short periods and deducing the place of the radiant 

 for each of them, it was found that no displacements occurred 

 other than those which might be fairly attributed to errors in 

 registering the paths. The radiants came out as follow : — 



July 23-25 ... 

 July 26-31 ... 

 August 1-5 ... 

 August 6-13 ... 

 August 14, 1887 

 August 18-25 ■■• 



The centre of radiation, like that of the October Orionids, 

 appears, therefore, to be motionless, and it continues visible for 

 more than a month. In observing this stream care must be 

 taken not to confuse it with two other pretty rich and contem- 

 porary showers at 345^+0" and 339° -30°. The latter is near 

 the bright southern star Fomalhaut. 



In this department the observer's efforts have to be regulated 

 in a great measure by moonlight, and this year our satellite will 

 interfere in the earlier and later part of July. But it is probable 

 that, with suitable weather, the first indications of the Perseid 

 display may be well observed on about July 11-15. As the 

 radiant centre of this system travels E.N. E. with the time, the 

 observer should keep his materials for each night separate, and 

 determine the place of radiation on every date when the conform- 

 able paths are adequate for that purpose. This position can 

 scarcely be defined, either with safety or accuracy, when less 

 than five well-observed meteors have been registered from it. But 

 it is often satisfactorily obtained when two observers at separate 

 stations record the same meteor. In a case like this the evidence 

 is conclusive as to the position of the radiant, though it may be 

 rendered a little inexact by errors of observation. But in 

 instances where meteors are seen at one place only there are 

 possibilities of mistake in attributing the r.adiants, for these have 

 necessarily to be assumed from the directions of flight and 

 visible aspect of the objects observed. In the case of the 

 Perseid shower there is not, however, much probability that 

 serious errors will occur in this respect, but everything depends 

 upon the discrimination and discretion of the observer. 



