March ic, 1881] 



NA TURE 



44: 



pulled off by the action of electricity. The cathode of a vacuum- 

 tube was covered with chalk. It exhibits phosphorescence of 

 orange-yellow colour, while in a short time the tube-wall becomes 

 covered by a very delicate layer of chalk, without losing its 

 clearness and transparency, and phosphoresces like chalk. Puluj 

 believes that the yellow-coloured phosphorescence observed on 

 metallic cathodes is caused by the phosphorescence of the oxides 

 covering the metal. 



GEOGRAPHICAL NOTES 



At its annual meeting the Russian Geographical Society elected 

 as vice-president M. Semenoff, and Baron Osten-.Secken as his 

 "aid." The great Constantine medals were awarded to M. 

 Moushketoff, fur his geological researches in Central Asia, and 

 to M. Vanson, for his remarkable work on " Comparative Sta- 

 tistics of Russia," the two first volumes of which have already 

 appeared ; the Liitke gold medal was awarded to Baron Kaulbars 

 for his papers on the Lowlands of the Amu-daria ; the two great 

 gold medals instituted last year for ethnographical and statistical 

 researches were awarded to Dr. Pyasetzky for his work, 

 "Travels to China during the Years 1875-77," and to M. Rous- 

 soff for his statistical description of the Nyejin district. Small 

 gold medals were awarded to M. Nordkvist, who took part in 

 Nordenskjold's expedition ; to M. Potanin for his travels in 

 Mongolia ; to JI. Tyaghin, for meteorological observations on 

 Novaya Zemlya, and to M. Mainoff for anthropological explora- 

 tions among the Mordovian-^. Silver medals were awarded to 

 Mme. Treskina and to MM. Andrianoff, Unterberger, Polonsky, 

 Orloff, Skassi, Karatin, Zinovieff, Krasovsky, and Mikhalenko. 



We learn from the last number of the /zvcstia of the Russian 

 Geographical Society that the Society sends this spring M. 

 Polyakoff with an assistant for the exploration of Sakhalin 

 Island. M. Polyakoff will start from Odessa, on board of a 

 Russian ship, and proceed to Sakhalin, where he will stay 

 dm-ing a year ; thence he will go to the Mantchurian shore of 

 the Pacific for further explorations. 



The explorer Begaert has arrived at Lisbon. He was sent by 

 the King of the Belgians to make scientific researches on the 

 route of Mr. Stanley at Vivi and other parts of Zaire. 



We are glad to learn that the U.S. Congress have decided to 

 appropriate 175,000 dollars to send out an expedition in a 

 whaling vessel in search of the missing steamer yeaiindlc, which 

 was sent out in 1879 by Mr. Gordon-Bennett to carry on Arctic 

 exploration by way of Behring Strait. The initiative in this 

 matter is due to Chief-Justice Daly, Presidei.t of the American 

 Geographical Society. 



In addition to two papers descriptive of the visits of Mr. 

 Leigh Smith to Franz-Jo- ef Land and Mr. Delmar Morgan to 

 Kuldja, the new number of the Geographical Society's Proceed' 

 ings gives Mr. F. C. Selous' notes on some of his many journeys 

 in South Central Africa, those dealt with here being to the 

 north of the Zambesi between the 27th and 29th meridians, 

 and in the neighbourhood of the River Chobe which empties 

 into the great river above the Victoria Falls. We gave last 

 week the text of the interesting note on Col. Prejevalsky, in 

 addition to which we may refer to the record of some altitudes 

 recently determined in Matabele Land, and a note of I'r. Oito 

 Finsch's explorations in Polynesia. The maps this month are 

 of the South Coast of Franz-Josef Land and the Central 

 Zambesi region. 



We observe that M. Henri Dnveyrier's interesting observa- 

 tions on the question of the sources of the Niger appear in the 

 last (December) number of the French Geographical Society's 

 BuUeliii, but we regret to find that they are published without a 

 map. 



In last week's issue of Les Missions Catholiqucs Mgr. Lavi- 

 gerie. Archbishop of Algiers, commences an account of the 

 missions of Equatorial Africa, with the direction of which he 

 has been charged. There is also a letter from Pere Antonin de 

 Reschio in Brazil, in which will be found some notes on curious 

 traditions among the Indians. 



Marquis Antinori and the other members of the Italian 

 expedition to Shoa are expected shortly at Zeila. It is also stated 

 that Signor Libman, an Italian traveller, has gone to Assab in 

 order to make an attempt to open commercial relations with the 

 interior and to survey some of the little-know n regions in the 

 neighbourhood. Signor Giuletti, who accompanied the Italian 



official representative to Assab in January, is charged by the 

 Italian Geographical Society to undertake a journey through the 

 country of the Danakil and Adel tribes, and to study the best 

 means for opening a trade-route between Assab and Abyssinia. 

 His mission has considerable geographical importance, as the 

 region to be traversed is unknown, and he will have an oppor- 

 tunity of solving the problem of the River Gualima, which 

 probably he found to empty into some lake in the interior, as 

 the Hanash does, if indeed it be not part of the latter river- 

 system, 



Capt. Neves Ferreira, Governor of Benguela, and other 

 Portuguese officers, have placed their services at the disposal of 

 the Lisbon Geographical Society for a scientific expedition across 

 Africa, to start from the West Coast. 



The Sydney Morning Herald of January 17 publishes a 

 telegram from their Queensland correspondent as follow's, dated 

 January 14 :— " Skuthorpe arrived two days ago from his ex- 

 ploring trip out west. He reports having travelled 200 miles 

 inside the South Australian boundary, and in the Herbert River 

 discovered relics of Leichhardt, consisting of his diary and 

 Classen's diary ; also a telescope with presentation engraving, 

 compasses, and other things. These, he alleges, are in two 

 packs \\hich he has brought with him. The diary of Classen is 

 to the effect that he left Leichhardt at the Saltwater Creek while 

 he searched for water, and that on his returning he fcund_ the 

 party dead, and then joined the blacks, w'th whom he lived 

 until three years ago. Skuthorpe will not allow any one to 

 inspect the alleged relics, and here it is considered doubtful 

 whether they are genuine." 



Intelligence has been received at the Foreign Office from 

 Her Majesty's Consul at Mozambique, which confirms the report 

 of the deaths of Capt. Phipson-Wybrants and Messrs. Carr and 

 Mears, of the Wybrants' expedition. Mr. Mayes is stated to be 

 at Umzeilas, and Mr. Owen to have left with the remainder for 

 Inhambane, whither Her Majesty's ship Ruby will proceed 

 forthwith. 



ON THE VISCOSITY OF GASES AT HIGH 



EXHAUSTIONS^ 



II. 



TNFL UENCE of Aqueous Vapour on Ike V^iscosity 0} Air.— In the 



foregoing experiments many discrepancies were traced to the 



presence of moisture in the gas. The influence of aqueous vapour 



does not appear to be great v hen present in moderate amount in 



gas of normal density, but at high exhaustions it introduces errors 



which interfere with the uniformity of the results, A series of 



experiments were accordingly undertaken to trace the special 



action of aqueous vapour when mixed with air. 



Up to a pressure of about 350 niillims. the presence of 

 aqueous vapour has little or no influence on the viscosity of air. 

 The t«o curves are in fact superimposed. At this point, how- 

 ever, divergence commences, and the curve rapidly bends_over, 

 the viscosity falling from 0-0903 to 0-0500 between 50 and 7 

 millims. pressure. Here it joins the hydrogen curve, and 

 between 7 millims. and I millim, they appear to be identical. 



These results are partly to be explained by the peculiar action 

 of water vapour in the apparatus. At the normal pressure the 

 amount of aqueous vapour present in the air, supposing it to be 

 saturated, is only about thirteen parts in a million, and the 

 identity of the log dec. with that of dry air shows that this 

 small quantity of water has no appreciable action on the viscosity. 

 When the pump is set to work the air is gradually removed, 

 whilst the aqueous vapour is kept supplied from the reservoir of 

 liquid. As the exhaustion approaches the tension of aqueous 

 vapour, evaporation goes on at a greater rate, and the vapour 

 displaces the air with increasing rapidity ; until, after the 

 pressure of 12-7 millims. is passed, the aqueous vapour acts 

 as a cas, and, being constantly supplied from the reservoir of 

 water" (as long as it lasts), washes out all the air from the 

 apparatus the log dec, rapidly sinking to that of pure water gas. 



This explanation requires that the viscosity of pure aqueous 

 vapour 'should be the same a^ that of hydrogen, at all events 

 between 7 millims, and I millim. pressure. The facts can, 

 however, be explained in another vvay. During the action of 

 the Spren<rel pump sufficient electricity is sometimes generated 

 to render the fall tubes luminous in the dark. It is conceivable 



■ Abstract of a paper read before the Royal Society, February 17, i88r, 

 by William Crookes, F.R.S. Continued from p. 423, 



