Nov. 20, 1884] 



NATURE 



65 



A LARGE Horticultural Exhibition is to be held at Berlin in 

 September 1SS5. 



A coffee plantation has been established by a landowner in 

 the neighbourhood of Rome. It is stated that he realised a fair 

 profit with this year's harvest, which consisted of 2 tons of coffee 

 per hectare. 



A new mud-crater has formed at the foot of Mount Etna, 

 measuring some 500 metres in diameter. The mud ejected by 

 it flows towards Monte Furmento and the pine forest of Bianca- 

 villa. 



The additions to the Zoological Society's Gardens during the 

 past week include a Vervet Monkey (Cercopithecus lalandii 9 ) 

 from South Africa, presented by Mr. J. A. Cameron ; an Asiatic 

 Wild Ass (Eijuiis onager £ ) from South- Western Asia, pre- 

 sented by Lieut. -Col. R. A. Crawford ; a Short-eared Ovt\(Asio 

 bracliyotns). a Lesser Kestrel {Tinnnnculus cenchris) from 

 Griqualand West, South Africa, presented by Mrs. L. Weil ; a 

 Common Cormorant (Phalacrocorax carlu), British, presented 

 by Mr. S. S. Mossop ; a Macaque Monkey (Macacus cynomolgus) 

 from India, deposited; two Tasmanian Wolves (Thylacinus 

 cynocephalus) from Tasmania, a Reindeer (Rangifer tarandus £ ) 

 from Labrador, a Golden-winged Woodpecker (Colaptts aura/us) 

 from North America, a South American Rat Snake {Spilotes 

 variabilis) from South America, purchased. 



OUR ASTRONOMICAL COLUMN 



The Saturnian System. — Dr. W. Meyer, late Assistant 

 Astronomer at the Observatory of Geneva, has published in 

 t. xxix. of Mimoires de la Socicte de Physique et d ' Histoire 

 Nafurelle de Geneve a determination of the dimensions of Saturn's 

 rings and of the orbits of six satellites, and the mass of the 

 planet, founded upon observations made at the Observatory, 

 with a filar-micrometer on the Merz refractor of 10 inches 

 aperture, presented to that institution by the late Prof. Plant- 

 amour. The observations in question were made during the 

 opposition of 1SS1, and upon a system which it was believed 

 would give the measures a superiority over those obtained with 

 the same instrument in the previous year. The memoir on 

 Saturn and his satellites, which has been separately published, 

 is preceded by a very minute description of the Plantamour 

 equatorial by Prof. Thury. The measures are printed in detail 

 with the elements of reduction employed ; they extend from 

 August 15 to December 19. Dr. Meyer considers that Mimas 

 was certainly observed on five nights, though he remarks : 

 " Meme dans la colossale lunette de Vienne, c'est un objet tres 

 delicat, qui est rarement visible quand il n'est pas pres d'une 

 elongation." On November 4, at ioh. 31m., a very faint 

 object was observed, approximately in the position — x = 254", 

 y = - 35", which, by means of Prof. Asaph Hall's ephemeris, 

 Dr. Meyer identifies as Hyperion. In the discussion of the 

 orbits of the satellites (Enceladus, Tethys, Dione, Rhea, Titan, 

 and Japetus) provisional elements are assumed, and are cor- 

 rected in the usual manner by equations of condition. In order 

 to determine the mean motions, the Geneva results are com- 

 pared with those of Bessel in the case of Titan, while for other 

 satellites the comparison is made with the epochs deduced by 

 Jacob from his measures at Madras in the years 1856-58, it 

 being considered that, in view of the precision attaching to 

 them, little would be gained by having recourse to the older 

 observations, especially as difficulties attend their explanation in 

 many cases. 



The mass of the ring is concluded to be very minute, certainly 

 very much less than the value assigned by Bessel ; it is stated 

 that with the aid of Tisserand's theory, taken in connection with 



the results of observation, was found for a higher limit. 



1647 

 The most probable mass of the planet deducible from the Geneva 



observations is — - — , agreeing within the probable error with 



34»2 "5 

 that assigned by Jacob, and that derived by Prof. Asaph Hall 

 from the Washington measures of Japetus. 



The following are the periods of the satellites and their mean 

 distances from Saturn, determined by Dr. Meyer : — ■ 



Sidereal Mean distance 



revolution In arc In equatorial 



d. h. m. s. „ radii of Saturn 



Enceladus ... 1 S 53 6-92 ... 34'35o ... 3-866 

 Tethys ... I 21 lS 2562 .. 42751 ... 4'8l2 



Dione 2 17 41 9-29 ... 54'757 ■•• 6 ' l6 3 



Khea 4 12 25 11 -57 ... 76-484 ... 8'6o8 



Titan 15 22 41 23-16 ... 176910 ... 19-91 1 



Japetus ... 79 7 49 24-84 ... 514-711 ... 57'93° 

 The Variable Star U Geminorum. — Mr. Knott has suc- 

 ceeded in observing another maximum of this irregular variable, 

 which appears to have taken place on October 22, though there 

 was very little change for four days after that date. On 

 October 18 it was below 13-3 m. From his previous observa- 

 tions compared with this one, Mr. Knott infers that there has 

 been a double period in 160 days. 



Encke's Comet. — M. Otto Struve has notified that an 

 ephemeris of this comet, extending from the beginning of the 

 present month to the beginning of May next, has been prepared 

 by Dr. Backlund, and that it was intended to communicate it to 

 astronomers direct from Pulkowa. 



Wolf's Comet. — M. Gonnessiat, of the Observatory at 

 Lyons, has calculated elements of this comet from observations 

 extending over forty-five days : he finds the period of revolution 

 6-862 years. The following ephemeris is deduced from his 

 orbit : — 



At Paris Midnight 

 R.A. N.P.D. Log. distance Intensity 



h. m. s. from Earth of light 



November 21. ..22 57 13 ... 93 60 ... 00035 ••■ °'74 

 23. ..23 2 11 ... 93 31-4 



25. ..23 7 11 ... 93 54-9 ... 0-0169 ... 0-70 

 27. ..23 12 13 ... 94 16-4 



29. ..23 17 18 ... 94 36-0 ... 0-0300 ... 065 

 December I. ..23 22 23 ... 94 53-8 



3. ..23 27 30 ... 95 9-8 ... 00425 ... o - 6l 

 The intensity of light on September 21 is taken as unity. 



GEOGRAPHICAL NOTES 

 At the last meeting of the French Geographical Society Dr. 

 Paul Heis read a paper upon the results of his journey through 

 the valley of the Meikong, and further north into the un- 

 explored region which separates Indo-China, properly so-called, 

 from Tonquin. Dr. Heis has made several discoveries likely to 

 be of service to anthropologists, geologists, ar.d mineralogists, 

 and has brought back with him a collection of insects and 

 reptiles, as well as a meteorological register, which was checked 

 four times a day during the whole of his journey. Leaving 

 Saigon on December 12, 1882, he ascended the Meikong as far 

 as the 18th parallel, at which point he turned off from the main 

 stream in order to go up its affluent, the Nancham, and en- 

 deavoured to reach Luang- Prabang through the hitherto un- 

 explored region known in Annam as the principality of Tranninh. 

 This region is infested by Chinese brigands, called Hos, who 

 drove him back to the Meikong, and seized the greater part of 

 his baggage. Reascending the river to Luang-Prabang he 

 remained there for eight months, exploring the country in various 

 directions, notably along the Nancham, which took him close to 

 the region of the Hos, so that he was again compelled to retrace 

 his steps. Being prevented from returning eastward, lie went 

 through the Siamese part of Burmah, reascended the Meikong 

 as far as Chieng-sen, thence, passing from the basin of the 

 Meikong to that of the Meinam, he reached Chieng-mai, and so 

 made his way on foot to Bangkok, following the course of the 

 Meinam. From Bangkok he went to Chantalun, on the west 

 coast of Siam, and thence on foot to Baltambang, traversing the 

 plain of the Saphyrs, where 4000 Burmese are employed in the 

 search for precious stones. After visiting the ruins of Angkor, 

 he reached Saigon on June 12 last. 



The oldest Geographical Society in Europe has hitherto been 

 regarded as that of Paris, founded in 1S21, but according to a 

 paper recently read before the Verein fiir Erdkunde at Dresden 

 by Dr. Ruge, this honour belongs to the " Cosmographic 

 Society" of Nuremberg. It was established about 1740, and first 

 came before the public in 1746, and was connected with 

 Homann's establishment in Nuremberg. The founder of the 

 latter was the well-known cartographer, Johann Hominn, on 



