88 



NATURE 



[Nov. 2 2, 1888 



Brazilian expeditions to observe the transit of Venus of December 

 1882. The vohime, which is a handsome quarto of some 750 pages, 

 and is fully illustrated with photographs of the various stations 

 and instruments, contains reports from three stations, the weather 

 at the Imperial Observatory at Rio de Janeiro itself, which should 

 have been a fourth station, having proved cloudy and wet. It 

 had been at first intended to send an expedition to Cuba, but as 

 the French astronomers were to occupy a position there, the little 

 Island of St. Thomas, belonging to Denmark, was chosen instead. 

 St. Thomas paired well with the southern station, Punta Arenas, 

 in Patagonia, for the duration was much shortened at the former 

 place and slightly lengthened at the latter, the sun being high at 

 both stations, and ingress and egress at both taking place nearly 

 symmetrically with regard to the meridian. The entire transit 

 was also teen from the remaining station, Olinda, near Pernam- 

 buco, where ingress was somewhat retarded and egress much 

 accelerated. The observations wei-e all made by the method of 

 projection, in order that the disturbing effectsof irradiation might 

 be got rid of as far as possible. The St. Thomas expedition 

 which was under the command of Baron de Tefife, possessed three 

 equatorials, and Dr. H. Draper had promised to supply a photo- 

 heliograph, but his lamented death prevented the carrying out of 

 his generous intention. The Olinda expedition, commanded by 

 M. J. de Oliveira Lacaille, had two equataials; whilst M. Cruls, 

 the chief of the Punta Arenas party, had but one ; the largest 

 telescope in each case being 6j inches in aperture. M. Cruls 

 selected a site for his party within a mile of that occupied by Dr. 

 Auwers with the (lerman expedition ; for the Brazilian Parliament 

 having delayed the necessary credit for the expedition to the last 

 moment, the expedition did not arrive at the place until late, and 

 it seemed better to take advantage of the German choice of 

 position rather than lose time by surveying for a fresh site at a 

 distance. The observations at each of these three stations were 

 successful, the second internal contact being observed at all, but 

 the first internal contact was lost at St. Thomas. The method 

 of chords could not, therefore, be employed, bat the combination 

 of the second contacts of the two northern stations with both 

 contacts of the southern gave 8""8c>8 as the resulting parallax. A 

 large part of the volume is devoted to a report of the voyage of 

 the corvette Parnahyba, by Captain L. Saldanha de Gama, the 

 captain who conveyed the southern observing party to their station, 

 and to a description of the natural history of Tierra del Fuego. 

 The Tail of Comet 1S87 a (Tmome). — Prof. Bredichin 

 has discussed in the Bulletin of the Imperial Society of Naturalists 

 of Moscow, 1888, Nos. 2 and 3, the observations of the direction 

 of the tail of this comet. The comet was discovered by Mr. 

 Thome, of Cordoba, on January 18, 1887, and it was remarkable 

 for the fmallness of its perihelion distance, the complete absence 

 of any nuclear condensation in the head, and the length, straight- 

 ness, and narrowness of the tail. Prof. Bredichin finds that the 

 tail manifestly belongs to his third type, viz. those in which 

 the repulsive force, i — ;u, does not exceed O'l. He suggests, as 

 the rate of outflow in comets of short perihelion distance is much 

 more rapid at perihelion passage than later, and as the comet was 

 not discovered until a week after perihelion, that the lighter 

 materials may already have been driven off and reduced to such 

 a degree of tenuity as tc be invisible, leaving only substances of 

 heavy atomic weight. As is well known, he associates his first 

 type of tail, that in which the repulsive force is greatest, with 

 hydrogen, the more ordinary second type with the hydrocarbons ; 

 and he suggests in the case of the present comet that elements 

 with atomic weights like those of gold, mercury, and lead, would 

 furnish a tail of the character observed. Some comets, however, 

 which do not approach the sun closely, have tails only of the 

 third type. If, then. Prof. Bredichin's explanation is to be re- 

 ceived in its entirety, hydrogen and hydrocarbons are not always 

 constituents of cometary tails. 



ASTRONOMICAL PHENOMENA FOR THE 



WEEK 1888 NOVEMBER -zs— DECEMBER i. 



/"pOR the reckoning of time the civil day, commencing at 



^ Greenwich mean midnight, counting the hours on to 24, 



is here employed.) 



At Greenwich on November 25 

 Sun rises, 7h. 38m. ; souths, lib. 47m. ig'os. ; sets. I5h. 57m. : 

 right asc. on meridian, i6h. 67m. ; decl. 20° 54' S. Sidereal 

 Time at Sunset, 2oh. 17m. 

 Moon (at Last Quarter November 26. I7h.'^ rises, 2lh. im.*, souths 

 4h. 56m. ; sets I2h. 40m. : right asc. on meridian, gh. 147m, ; 

 decl, 18" 7' N, 



Right asc. and declination' 



Planet, Rises. Souths. Sets. on meridian. 



h. m, h, m, h. m. h. m. o / 



Mercury.. 5 53 ... 10 38 .„ 15 23 .„ 14 57-0 ... 14 59 S. 



Venus 10 37 ... 14 18 ... 17 59 ... 18 37-4 ... 25 2 S. 



Mars II 30 .„ 15 29 ,„ 19 28 ... 19 491 ... 22 32 S. 



Jupiter..,. 8 32 ... 12 33 ... 16 34 ... 16 52*1 .., 22 6 S. 



Saturn.... 21 48*.., 5 14 ... 12 40 ... 9 32-2 ... 15 37 N. 



Uranus... 3 31 ... 8 57 ... 14 23 ... 13 i6-o .„ 7 23 S. 



Neptune,, 15 50 ... 23 35 ... 7 20*... 3 56-2 ... 18 39 N. 



* Indicates that the rising is that of the preceding evening and the setting 

 that of the following morning. 



Occultations of Stars by the Moon (visible at Greenwich). 



Corresponding 

 angles from ver- 

 Disap. Reap. tex to right for 



inverted image. 



Nov. 



Star. 



Mag. 



7 25 near approach 17S — 

 I 44 near approach 301 — 

 5 59 near approach 124 — 



26 ... 37 Leonis ... 6 

 28 ... B.A.C, 3996 ... 6 

 30 ... B.A.C. 4572 ... 6 

 Nov. h. 



25 ... 13 ... Saturn in conjunction with and 1° 31' south 

 Dec. of the Moon. 



I ... II ... Saturn stationary. 



Variable Stars. 



Star. R.A. Decl. 



h. m. „ , h. m. 



U Cephei o 52-4 ... 81 16 N, ... Nov. 25, o 27 w 



,, 30, 06m 



S Arietis 2 9-8 ... 24 32 N. ... Dec. i, m 



\ Tauri 3 545 ... 12 10 N. ... Nov. 26, 20 44 m 



„ 30, 19 36 m 

 C Geminorum ... 6 57*5 ... 20 44 N, ... ,, 29, 2 o ;« 

 R Canis Majoris... 7 14-5 ... 16 12 N. ... ,, 25, o 41 w 



,. 26, 3 57 m 

 U Monocerotis ... 7 25-5 .. 9 33 S. ... ,, 27, m 



U Hydrse 10 320 ... 12 48 S. ... ,, 26, m 



S Leonis 11 5-1 ... 6 4 N, ... ,, 30, M 



R Scuti 1841-5... 5 50 S. ... ,, 29, M 



V Aquilse 19 46-8 ... o 43 N, ... ,, 29, 18 o m 



T Aquarii 20 440 ... 5 34 S. ... ,, 27, m 



T Vulpeculse ... 20 467 ... 27 50 N. ... ,, 29, 21 oM 



„ 3 >, 22 o m 



Y Cygni 20 47*6 ... 34 14 N, ... ,, 25, 2 iS m 



,, 28, 2 12 m 



5 Cephei 22 25*0 ... 57 51 N. .., ,, 25, 4 oM 



,, 28, 21 o m 



M signifies maximum ; m minimum. 

 Meteor-Showers. 

 The most interesting periodical shower of the week is that of 

 the Andromedes, the stream connected with Biela's comet, but 

 no remarkable display can be expected from it this year : max. 

 Nov. 27 ; radiant about R.A. 25°, Decl, 44° N, Other showers of 

 the week are as follow : — 



R,A, Decl, 



NearA.Persei 60 ... 50 N. ... Very swift, 



,, & Canum Venaticorum 190 ... 42 N. ... Swift; streaks. 



GEOGRAPHICAL NOTES. 



Two letters relating to Dr, Nansen's expedition across Green- 

 land have been published — one from Dr. Nansen himself to 

 Mr. Augustin Gamel, Copenhagen, who is defraying the expenses 

 of the expedition ; the other from Mr. Sverdrup, one of Dr. 

 Nansen's companions, to his father. The letters were sent 

 forward from Godthaab by two kajak-va&n, who delivered them 

 to the captain of the Fox, at Ivigtut, The following is a transla- 

 tion of Dr. Nansen's letter : — 



Godthaab, October 4. 



I have at last the great joy to report to you that Greenland 

 has been successfully crossed from east to we.-t. I regret that 

 the very short time left to me before despatching my messengers 

 will not permit any detailed account, I can just jot down a 

 few words to be forwarded by the kajak-mQU. I am sending 

 southwards in the hope of stopping the Fox at Ivigtut, and 

 getting her to wait for us and take us home this autumn. But 



