88 



NATURE 



[November 24, 1892 



Africa, presented by Mr. B. B. Weil ; two Jackdaws ( C^r»«j 

 monedula, white var.) British, presented by Mr. Harding Cox, 

 F.Z.S.; eighteen Deadly Snakes {Trigonocephalus atrox) horn 

 Demerara, presented by Mr. J. J. Quelch, C.M.Z.S. ; a Com- 

 mon Chameleon {Chamaleon vulgaris) from North Africa, 

 presented by Mr. J. Pettitt ; a Blue and Yellow Macaw [Ara 

 ararauna) from South America, deposited ; four Lapland 

 Buntings {Calcarius lapponicus), twelve Snow Buntings {Plectro- 

 phanes nivalis) European, six Cirl Buntings {Emberiza cirlus) 

 British, purchased. 



+ 38 19 25-8 

 + 38 19 4-5 



+ 37 53 6-2 



+ 37 52 587 



+ 37 52 57-9 



+ 37 52 50'6 



+ 37 52 48-6 



OUR ASTRONOMICAL COLUMN. 

 The New Comet. — The following observations of the 

 "Comet Holmes" are communicated to the Comptes rendus 

 by M. Bigourdan, Paris Observatory : — 



Paris App. App. 



Mean Time. R.A. Decl. 



s. h. m. s. 



o 45 55-51 

 o 45 53*46 

 o 44 376 

 o 44 317 

 o 44 3-01 

 o 44 271 

 o 44 2-33 



On November 9 the comet was a large and bright nebulosity, 

 perfectly round, and 5''5 in diameter. It showed a central 

 diffused nucleus, 10" in diameter. A rather brighter portion of an 

 approximately elliptic form appeared to extend from the nucleus 

 in the direction / = 127°, its axes being i'-5 and 30" respect- 

 ively. On November 13 the comet was only seen intermittently. 

 It was 8' in diameter and nearly round. The nucleus no longer 

 occupied the centre, but had shifted towards the preceding por- 

 tion. The elliptical region was 2' by 30", and in the direction 

 /= li6°-8. To the naked eye it was easily visible, being as 

 bright as the Andromeda nebula near it, but less easily distin- 

 guished, owing to its smaller apparent size. 



The m.ost recent elements and ephemeris have been obtained 

 from observations made on November 9 at Karlsruhe, Novem- 

 ber 10 at Rome, and November 11 at Gottingen, and are given 

 in Astronomiche Nachrichten, No. 3128, from which we make 

 the following extract : — 



Elements. 

 T = i892 August 15 779 M.T. Berlin. 

 CO = 300° 2' 7 ~j 



S= II 25-9 j- M. Aequator, 18920 

 i = 27 34 o J 

 log^= 9-92222 



Ephemeris for 1 2h. Berlin M. Time. 



1892 a. fi logr logA 



Nov. 17 oh. 43-5 +3732 0-2562 9 '9734 

 ,, 21 437 II o'2688 00071 



,, 25 o 44-7 -i-3650 0-2810 00387 



The comet can be easily picked up with a small telescope by 

 knowing that it lies in a line joining the stars )8 and Q Andro- 

 medse, about one-third of the distance from fi. 



Motion in the Line of Sight. — The transformation of 

 the great reflector of the Paris Observatory for the purpose of 

 adapting it to the spectroscopic determination of radial velocities 

 is described by M. H. Deslandres {Comptes rendus 20). Instead 

 of having a flat mirror at 45°, a collimator was placed in the 

 optic axis itself, and movable along it. The rest of the spectro- 

 scope, which contained three flint prisms and a camera, was 

 enclosed in a rigid steel box attached to the upper ring of the 

 telescope. In order to control the motion, the plates forming 

 the slit were made of polished steel and slightly inclined, so as 

 to throw an image of the sky down into an auxiliary telescope 

 inside the tube, which was provided with a reflecting eye-piece. 

 Thus the observer below, standing near the great mirror, was 

 enabled to keep the star well on the slit. With this arrange- 

 ment, spectra of stars down to the 4th magnitude could be 

 obtained, 12 cm. long, in two hours. In the blue portion a dis- 

 placement of 0-005 mm. indicated a velocity of 3-6 km. per 

 second. The lines whose displacements were measured were those 

 of hydrogen, calcium, and iron. 250 stars are within reach of the 



NO. 1204, VOL. 47] 



instrument. For a Aurigse, with a comparison of 30 lines, the 

 velocity was -I- 43*5 km. ^ Aurigse is a spectroscopic double 

 with velocities, on February 5, of — 84 km. and + 97 km. 

 Venus, on April 12, had an actual velocity of 13-55 km. That 

 indicated by the negative was 15 km. 



" Himmel und Erde" for November. — The current 

 number of Himmel und Erde contains many astronomical 

 articles of interest. " The Heat in August, 1892" is the sub- 

 ject of an article by Prof W. J. van Bebber. In this he brings 

 together all the statistics of the temperature readings during 

 the interval between August 11 and 25, and shows by weather 

 charts the general state of the weather, such as wind, baro- 

 meter, &c. The following few values, showing the highest 

 temperatures recorded and extracted from the table mentioned 

 above, may be of interest : — 



Place. 



London 



Oxford 



York 



St. Petersburg 



Stockholm 



Paris 



Biarritz 



Brussel 



Place. 



Cassel 



Griinberg 



Karlsruhe 



Bamberg 



Constantinople 

 Madrid 



Rome 



Lagouat 



A"^- ^/aZ- 



17 

 19 

 17 

 18 

 21 

 16 



17 

 17—21 



23 



968 

 102 -2 



96-8 

 100-4 

 100-4 

 107-6 

 1076 



93-2 

 105-8 



Dr. J. Scheiner, on " Astronomy of the Invisible," deals with 

 the discovery of the dark companions of Sirius and Procyon. 

 He commences with an historical sketch of the study of the 

 proper motions of the fixed stars and leads up to the most 

 modern observations describing the results obtained with regard 

 to Sirius and Procyon. Prof. Barnard, with the help of two 

 excellent woodcuts, explains the working of the great Lick re- 

 fractor. To prepare the instrument for micrometric work, he 

 says five minutes is required ; but for photographic work ten 

 minutes is necessary, as a photographic correcting lens has to be 

 adjusted to compensate for the difference between the photo- 

 graphic and optical focus ; the large spectroscope absorbs 

 nearly half an hour's work before it is ready for observation. 



Observations of Perseids. — During the August display 

 of the Perseids it has been noticed that in addition to the 

 principal radiant point several minor ones have been observed, 

 which although not very far distant from the primary one, are 

 still far enough to suggest that they belong to another swarm of 

 particles following a different track in space. The orbit, which 

 the particles in the main follow, corresponds, as is well known, 

 to that of the comet of 1862 III., and M. Bredikhine has sug- 

 gested that the particles producing these minor radiant points 

 belong really to the same swarm, only have either been acted on 

 by external forces such as the perturbations of the major planets, 

 or have been projected from the comet itself at different 

 periods. 



With the intention of bringing some facts to bear upon this 

 idea, M. Puiseux, in the Btilletin Astronomique for October, 

 gives the results of his observations made in August of last year, 

 which tseem to confirm those of M. Bredikhine in several 

 points of view. 



His method of observation was simply to chart down on a 

 large celestial globe the positions of the trails as observed. A 

 glance at this globe, after 199 positions had been so recorded,, 

 indicated that the area of radiation occupied a consider- 

 able surface, and extended principally in the directions of right 

 ascensions, that several distinct centres of concentration were 

 observable, and that the same radiant points, in general, mani- 

 fested their activity at the same time, i.e., on the evenings of 

 August 10, II, and 12, and some on August 7. In the table 

 accompanying this paper M. Puiseux shows that no less than 

 fourteen different centres of radiation were observed. Table If., 

 which we produce here, contains the essence of the whole work, 

 and shows the positions of the radiant points in question, 

 together with the corresponding elements of the orbits deduced. 

 It must be remembered of course that their values cannot be 

 very accurate, owing to the difficulty of observation, but the 

 results are nevertheless interesting. The different radiant 

 points are denoted by A, B, C, &c., while a and S represent 



