April 17, 1884J 



NA TURE 



585 



though it is unavailable for riding and for beasts of burden. Dr. 

 Junker closes his remarks on the hydrography of this region 

 with the observation that he feels entitled to identify this 

 Nepoko, which does not belong to the Welle system, with the 

 Aruwimi of Stanley. Proof that the Welle is the upper course 

 of the Shari'he hopes to be able to adduce later on. 



In Petirmann''s Mitlheilungat, 1S84, Heft iii., is a map of the 

 .\mambara Creek of the lower Niger region, which we owe to 

 the indefatigable .Xfrican explorer Eduard Robert Flegel. Just 

 as by way of preparation for liis Adaniawa expedition he executed 

 maps of the route from Eggan to the Akoko Mountains, and of 

 the Niger tract, till then unknown, from Bussa up the river as 

 far as Gomba, and finally explored the route from Bidda by 

 way of Keffi Abd-es-Senga to Loko on the Benue ; so now as 

 preparatory to his third .African exploration he has executed a 

 map of the Amambara w^hich discharges into the lower course of 

 the Niger. While Flegel was waiting at Lagos for a remittance 

 from Germany to enable him to prosecute his travels, the 

 representative of the Marseilles "Compagnie du Senegal et de 

 la Cote occidentale d'.\frique," J. Zweifel, the well-known dis- 

 coverer of the sources of the Niger, undertook in July 1883, for 

 trading purposes, an expedition up the Amambara, on the banks 

 of which are planted a series of old commercial establishments, 

 but which, nevertheless, had never yet been mapped out. To 

 this expedition Flegel at once gladly joined himself, and hence 

 the map in question. This must be reckoned as another vahjable 

 contribution towards clearing up the geography of the Lower 

 Niger, so complicated by tributaries, arms, deltas, creeks, &c. 

 In an article in the Mittlidluxgin commenting on the map of the 

 Amambara Creek, an interesting sketch is given of the progress 

 of geographical knowledge of the Niger for the last 300 years, 

 or rather of the misconception and vacancy that prevailed up till 

 quite recently regarding that region, our knowledge of which is 

 still so very defective. Since the discovery of the rich produce 

 in palm-oil yielded by the banks of the Niger and Lower Benue, 

 trade has rapidly developed there, and is now so lively that 

 Flegel, in 1883, counted as many as twenty-three large ships, 

 mostly steamers, constantly plying on their waters, besides a 

 series of flat barges. 



We find in the last issue ot the Caucasian Izvestia the follow- 

 ing new information on the Merv oasis, due to M. Alikhanoff : — 

 Its surface is about 2150 s([uare miles, which area could be 

 increased by irrigation, the whole of the oasis having its origin 

 due - the irrigation of the sands by canals drawn from the Mur- 

 gab. This river, being dug at Kaushut-khan-bend, two canals, 

 subdivided into numerous aryks (smaller canals), issue from it, 

 taking in nearly all the water of the river which does not flow 

 beneath the dam. Notwithstanding the southern position of the 

 oasis, it has a cold winter, and there falls every year some snow, 

 sometimes two feet deep ; it soon disappears, however, as the 

 temperature rises rapidly, and reaches occasionally 30° Celsius in 

 February. During the summer, strong hot winds, which bring 

 masses of hot sand, blow, mostly from the south-west. Still the 

 climate is healthy enough, and healthier than that of .\khal- 

 tekke ; but the mortality is very great, owing to the poverty of 

 the inhabitants and the dirtiness of their habits : the kara-masla, 

 or black disease, a kind of pestilence, and the merghi, a kind of 

 cholera, are endemic. The population is estimated at 32,700 

 kibilkas, which M. Alikhanoff' considers to represent no less 

 than 194,000 or 200,000 inhabitants. This population is, how- 

 ever, too numerous for the oasis, the average area of irrigated 

 land being only six acres per inhabitant. M. Alkihanoft con- 

 siders the Mervis as the least attractive of the Turcomans, and 

 discovers in them only one good feature — their hospitality. 



At the annual meeting of the Bremen Geographical Society 

 it was stated that a young German naturalist intends to start on 

 an exploring expedition to Ovambo-land and further into the 

 interior of Equatorial Africa, accompanied by Dr. Hoepfner. A 

 member of the. Society has presented him with good astronomical 

 instruments, and the traveller will report to the Society from 

 time to time, and his cartographic results will belong to the 

 Society. The Society is also preparing a geographical and 

 natural history expedition to the Bonin Islands, lying south of 

 and belonging to Japan. Dr. Gottsche of Kiel, an eminent 

 geologist, who is now in Japan, will be the leader of this 

 expedition. 



The Russian Imperial Geographical Society has received the 

 following telegram from Col. Prjevalsky, who is for the fourth time 

 attempting to penetrate into Thibet : — " Alashan, January 8. — 



We have traversed the desert of Gobi without mishap. In the 

 northern part the cold exceeded the freezing point of mercury. 

 We are all well, and start to-morrow for Koukou-nor. It is 

 said that hitherto the Thibetans pray heaven to shower down 

 stones on our heads." 



The Melbourne Age\\?is, despatched to New Guinea a second 

 exploring party, the members of which include a naturalist and 

 an artist. 



One result of Mr. Colquhoun's recent journeys in Indo-China 

 has been the appointment of an English official to reside at 

 Cheng-mai, or Zimme, on the borders of the Shan States, and 

 an officer of our consular service in Siam has been selected for 

 that purpose, and is now at the post. This town, it may be 

 recollected, forms the centre of the railway communication which 

 Mr. Colquhoun proposes between British Burmah and South- 

 western China, and it can be reached either from Rangoon or 

 from Bangkok. Mr. Bock travelled from the latter town up the 

 Meinam. With the example of the exploration of the English 

 consuls who have resided at Chung-king on the Yangtsze before 

 him, it is to be hoped that the consul at Zimme will be able to 

 add largely to our knowledge of the regions, especially of the 

 Shan States, lying between China and Siam. His appointrnent 

 is certainly another step in the prolonged efforts to obtain a 

 trade route into South-Western China, and he will serve, on the 

 south of the frontier line, the same purpose as the ofticer at 

 Chung-king on the north. 



VOLCANIC ASHES AND COSMIC DUST^ 

 TN the session of 1876, Mr. John Murray communicated to 

 ■'■ this Society a paper on the distribution of volcanic debris 

 over the floor of the ocean,- and in it announced the discovery 

 of cosmic dust in deep-sea deposits. It was shown that at 

 points where neither the action of waves, rivers, or currents can 

 transport the debris of continents, volcanic materials play the 

 most important role in the formation of the mineral constituents 

 of the deep-sea deposits. It was pointed out that pumice, on 

 account of its structure, was able to float to great distances, but 

 in time became waterlogged and sank to the bottom, there to 

 decompose. On the other hand, incoherent volcanic matters, 

 ejected in the form of lapilli, sand, and ashes, into the higher 

 regions of the atmosphere, may, ceteris paribus, be conveyed, in 

 consequence of their small dimensions and structure, to greater 

 distances than other mineral particles derived from the conti- 

 nents. The possibility was also admitted that submarine volcanic 

 eruptions might also contribute to the accumulation of those 

 silicates and pyrogeneous minerals and rocks whose microscopic 

 characters and distribution at the bottom of the sea we shall 

 presently point out. 



During the past few years we have added greatly to the 

 observations which were the subject of Mr. Murray's communi- 

 cation. The present paper has been suggested by the strikmg 

 analogy which exists between the volcanic products we have 

 found in all deep-sea sediments, and the ashes and incoherent 

 products of a recent celebrated eruption, — that of Krakatoa. 

 The remarkable meteorological phenomena we have recently wit- 

 nessed have been attributed by some to the presence in the atmo- 

 sphere of mineral particles derived from this volcanic eruption, 

 and by others to that of cosmic dust. It is said that in several 

 places in America, and even in Europe, matters have been col- 

 lected which must be regarded as the ashes from Krakatoa, which 

 have been suspended for several months in the upper currents of 

 the atmosphere. The importance of this matter has been recog- 

 nised by the Royal Society of London, which has appomted a 

 committee of its members to collect all the documents and obser- 

 vations relative to the distribution of these ashes. The present 

 state of the question induces us to make known some results of 

 the detailed researches which we have undertaken upon simylar 

 subjects. We desire to make known, to those who wish to study 

 atmospheric dust, the distinctive microscopic characters by the 

 aid of which we have been able to establish the volcanic or 

 cosmic nature of certain particles found in deep-sea deposits, and 

 to show at the same time the enormous area of the ocean over 

 which we have been able to detect their distribution. 



We believe that no better example could be found in support 



,' " On the Microscopic Characters of Volcanic Ashes and Cosmic Dust, 

 and their Distribution in the Deep-sea Deposits." A paper read before 

 the Royal Society of Edinburgh by Mr. John Murray and M. A. 

 Renard. 



= Proc. Roy. Soc. Editi., 1876-77. 



