July 14, 1881] 



NATURE 



^49 



show the increased scintillation most. The author's general 

 conclusion is that the effect is not one due to direct influence of 

 the electro-magnetic light of aurora on the scintillation itself, 

 but to disturbances (probably a cooling) which comcide with the 

 aiipearance of aurora in the upper regions of the air, traversed 

 by the star-rays. 



An acousti;al apparatus for lecture purposes, devised by Dr. 

 Maschke { Wud. Ann. No. 5), consi :.ts of a longish graduated 

 piece of wood on adjustable supports, and having a bngitudinal 

 groove in in its upper surface, in which a glass tube is placed. 

 At the end of the wooden piece is a screw arrangement support- 

 ing a thin steel rod which enters the tul^;, and has at its end a 

 (vertical) ring with collodion membrane, against \\ hich hangs a 

 little ball of shellac by a cocoon- fibre from the upper border. 

 The tube may be made a closed one by means of a felt-covered 

 piston. When the tube is sounded by means of a suitable 

 tuning-fork, the slieliac ball shows pendulum-motions, if not at 

 a nodal point. The effects may be projected on a screen. 



The passivity of iron has been studied under new conditions 

 by M. Bibart (your. A- Phys. , May), and he considers it is not pro- 

 duced by a layer of insoluble sub-nitrate, as some physicists 

 have thought, since the previous action of nitric acid is not 

 necessary. Still less is it due to a formation of bioxide of nitro- 

 gen. It is produced by any cause which tends to oxidise iron, 

 and destroyed by any cause which tends to deoxidize it. It is 

 due then either to a layer of oxide or a layer of oxygen. Tlie 

 oxides formed on the surface may preserve it by their very 

 presence, furni>hing a sort of unattackable varnish, or they 

 miy preserve it like platinum, liberating, on the denuded parts, 

 a protective layer of oxygen. The passivi'y of iron from con- 

 tact of platinum seems to be produced at first by a sample layer 

 of oxygen condensed on the platinum sm'face (a simple shock 

 destroys it). But by degrees a layer of oxide is formed, and the 

 iron then loses its passivity much less readily than before. 



GEOGRAPHICAL NOTES 

 Dr. Schweinfurth, who left Suez for Socotra on February 

 23, returned on June 19. From the Egyptian Gazette we learn 

 that his voyage to the island in a native vessel lasted one 

 month (with calls). He was a month on the island. The rich 

 fiora yielded many new species. The mountains are well 

 wooded, and covered with a more luxuriant vegetation than Mount 

 Etna. The climate is exceptionally temperate, and the natives 

 are inoffensi\e, greater security being experienced everywhere 

 than in any part of uncivilised Africa On the approach of tlie 

 south-west monsoon Dr. Schweinfurth had to leave, and in a 

 miserable native vessel he tried to reach the Arabian coast 

 opposite Socotra. It was found impossible to get to the east of 

 Aden, and in H.M.S. Dragon, which was met, the explorer was 

 conveyed to that place. Dr. Schweinfurth has brought with 

 him a rich botanical collection, including sjme living plants 

 which he will try to acclimatise in his garden at Cairo. 



The Polar relief ship Rodgers, Lieut. Berry, sailed from San 

 Francisco on June 16 in search of the Jeannettc. She will first 

 cruise to St. Berry, then proceed to Petropaulovsky, then cross 

 to St. Michael's in Alaska to coal, thence to St. Lawrence Bay 

 and along the coast of Northern Siberia, making inquiries of the 

 natives ; then from Cape Serge to Kamon, where letters will be 

 left with some native, ; then north to Herald Island, hunting 

 well over for cairns. It is intended next to go along the southern 

 shore of Wrangel Land, and seek a harbour to winter in. The 

 north-east and west coasts will be examined in sledge parties. 

 Lieut. Berry means to return, if possible, by the second year. 



Instructions have now been issued by Brigadier-General 

 Hazen, of the U.S. Signal Office, to the commanding officers of 

 the two expeditionaiy forces about to be sent out to establish 

 permanent stations of observation in Polar regions. Lieut. 

 Greely commands one of these forces, which goes to the neigh- 

 b:iurhood of the coal-.eam discovered near Lady Franklin Bay 

 in 1875. The steamer will directly return (with a transcript of 

 observations during the voyage), and the party landed will pro- 

 ceed to erect dwelling-Tiouses and ob-ervatories, after which a 

 sledge party will proceed to the high land near Cape Joseph 

 Henry. It is intended that the permanent station shall be 

 visited in 18S2 and 1883 by a steam-sealer or other vessel with 

 stores, &c., but directions in case of failure are supjilied. Lieut. 

 Ray cormiiands the other expedition, which will sail from San 

 Francisco for Point Barrow, Ala-ka Territory, and establish 



there a permanent station to be occupied till the summer of 

 1SS4 and visited annually. A great variety of observations will 

 be made by both parties, and the instructions drawn out by the 

 recent Hamburg Conference (with added notes from the U.S. 

 Chief Signal Office) are furnished. 



Dr. Ger.\rd Rohlfs delivered an interesting lecture at the 

 meeting of the Berlin Gesellschaft fiir Erdkunde regarding his 

 last journey in Abyssinia. He was received in a friendly manner 

 by the inhabitants, and he is quite charmed with the hospitality 

 of the Abys,inians. At Debratabor he was received kindly by 

 Negus (Emperor) Johannes, and this was of great i nportance for 

 his subsequent tour. Rohlfs travelled in a northerly direction to 

 the ancient Portuguese capital Gondar, the residence of the late 

 King Theodore. By means of a pass given to him by the 

 ecclesiastical chief of the city he was able to inspect all the 

 ancient historical buildings of the city. He continued his journey 

 to the north, and after crossing the Takkaze River he reached 

 Artum (Axum ?), the ancient former royal re.-idence, with its 

 monuments dating from the period of Ptolemy. In April Rohlfs 

 reached the Nassaur mountain chain, the boundary of Abyssinia, 

 whence he proceeded to Cairo by boat. 



The expedition sent out by the French Secretary for Public 

 Instraction to investigate the east coast of Finmarken has arrived 

 at Vadso after a journey of twenty-one days. The expedition, 

 which is under the command of il. Gso.'ges Pouchet, his for its 

 special object to study the natural history of theVaianger Fjord, 

 which is sitaated at the bouiulary of the Atlantic and Arctic 

 Oceans. The keeper of the Chri tiania Royal Zoological Collec- 

 tions joined the expedition at Hammerfest. 



The Emperor of Germany has honoured Dr. Oscar Lenz, the 

 well-known African traveller, with the Order of the Crown. 



Mr. S.^ndford Fleming, C.M.G., Engineer-in-Chief of the 

 Canadian Pacific Railroad, is to attend the International Geo- 

 graphical Congre-s at Venice in the interests of the que-tion of 

 standard time, coupled with wliich is that of a prime meridian. 

 The former of these subjects is attracting much attention on the 

 other side of the Atlantic, and a paper on it was lately read by 

 Mr. Fleming before the American Society of Civil Engineers 

 at a convention in Montreal, which brought out an interesting 

 discussion, and a committee, consisting of leading railway 

 officials in Canada and the United States, was appointed to 

 examine and report at a future meeting. Dr. Barnard, the 

 President of Columbia College, New York, is to represent the 

 American Meteorological Society on the same subject at a 

 meeting of the Association for the Reform and Codification 

 of the Law of Nations, which is to be held at Cologne in 

 August. 



Col. Perrier, a well-known French topographer, has lately 

 been for some time engaged in sur\ey work ni the Regency of 

 Tunis, and has prepared a map of the Kroumir country, which 

 will shonly be published by the Depot de la Guerre. 



Messrs. S. Clarke and J. LI. Riley, of the China Inland 

 Mission, whose station is at Chungking, formerly Mr. Colborne 

 Baber's he.ad-qnarters, have each lately male iaiportant journeys 

 in the Szechucn province. Mr. French, accomjianied in one of 

 his journeys by Mr. Broumton, has visited nearly every city in 

 Eastern ^ tinnau, and has lately started again for the same region, 

 lu the course of their journey from Bumiali Messrs. Soltan and 

 Stevenson also made extensive journeys in the western part of 

 the Vii'inan province. 



The steamer Nordenskjijld is to start this week for the Gulf of 

 Obi to the assistance of the Oscar Dickson and the Nordland. 

 The crews of these vessels were all safe on April 23, when five 

 men from the former left for Tobolsk, which they have lately 

 reached. 



A letter from Mussuca, on the Lower Congo, state- that a 

 Jesuit missionary expediti n has been set on foot to penetrate 

 into the far interior. Pere Argourd has been sent from the 

 French mission station at Landana to organise a party of about 

 thirty to proceed to Stanley Pool. lie tried to procure carriers 

 at Boma, Mu suca, and Noki, but not succeeding there, he went 

 some thirteen miles inland to King Kangan Pecca, with a view- 

 to secure his aid. This was readily obtained by a truly mis- 

 sionary present of two gallons of rum, and Pere Argourd returned 

 with eight men and the jiromise that seventeen more should be 

 sent shortly. The men however ran away the next day, and, 

 yielding to circumstances, Pere Argourd has resolved to proceed 

 to Stanley Pool by M. de Brazza's route up the Ogowe. 



