;22 



NATURE 



\_Sept. 29, 1881 



in Berlin, then, for greater quiet, in the Astrophy^icalisches 

 Observatoriiim at PotKlam (it was very sensitive to vibrations). 

 The interpretation of the results is that there is no displacement 

 of the interference bands, and the hypothesis (which is presup- 

 posed in the commonly accepted explanation of aberration) 

 is inferred to be erroneous. 



The expansi m of solid sulphur has been studied by S. 

 Scichilone of Palermo, in the case of natural crystals, and of 

 such as had been heated after fusion to 140° and 240°. The 

 tables {Wied. Bcibl., No. 7) show 'hat the expansion depends 

 essenti.iUy on the previous heating, inasmuch as different mrdi- 

 fications of sulphur are thereby formed. In the first case we 

 have the octahedral sulphur, in another the monoclinic, and in 

 the third a mixture of the latter with that which is not dissolved 

 in sulphide of carbon. In the first two cases the curve repre- 

 senting (he Volumes as a function of the temperature turns its 

 convex side, in the third its concave side, to the axis of 

 temperature. 



GEOLOGICAL NOTES 



The recent geological exploration of the shores of Lake Baikal 

 by M. Tchersky has been fruitful of important results for science. 

 The rocks of which the mountains on the western shore are built 

 up belong to three different ages: p-eSilurian (probably Lauren- 

 tian), Silurian, and Jurassic. ' he Laurentian rocks afford several 

 foldings running north ea-t, wliich enclosed basins of Silurian and 

 Jurassic seas ; as to recent formations they are only freshwater 

 ones, and belong to the Tertiary and Post-plircene ; these last, 

 which are remains of several smaller lakes, are found at a great 

 height above the level of Lake Baikal. M. Tchersky's geo- 

 logical researches confirm the suggestion which was made several 

 years ago on geographical grounds by M. Kropo'kin, namely, 

 that, like several other lakes. Lake Baikal consists of two 

 longitudinal valleys, connected together in the middle part of 

 the actual basin. 



The important conl-bain of the Don province of Russia has 

 not hitherto been explored with accuracy. During last «ummer 

 M. Domger undertook a thorough exploration of this interesting 

 geological region, and, as we learn from a communication he 

 has made at the December meeting of the St. Petersburg Mine- 

 ralogical Society, his researches have led to important discoveries. 

 Thus he discovered a great variety of crystalline recks, por- 

 phyries, &€., and volcanic ores, within the cr al-measures, which 

 discovery thus extends the crystalline island of Southern Russia 

 far eastwards as a strip about 500 miles 'ong, which runs from north- 

 west to south-east. At the same meeting the Society awarded 

 its gold medal to M. Komauoffs! y for his researches in 

 Turkestan. 



M. Dokouch.\ieff's researches on the soils of Rus-ia seem 

 to establish a very interesting fact as to the distribution of black- 

 earth. The typical black-earth occupies an elongated zone 

 directed from sonth-west to rorth-east from Ki-hineff, through 

 Khark. ff', Voronesh, Simbir,-k, to Bougoulina in the province of 

 Oufa ; in this zone the bkick-earlh contains from 7 to 12 per 

 cent, of humus, and from loth sides to north-west and south-east 

 it is accompanied by two other elongated zones, where the black- 

 earth contains only 5 to 7 per cent, of humus, whilst the other 

 parts of Russia aflbrd only sporadic spots of black-earth. 



M. Moushketoff's paper on the glacier of Zerafshan, which 

 appeared in a recent iiunjber of the Izvestia of the Russian Geo- 

 graphical Society, contains further details about the expedition 

 which has explored the g'acier thn ughout its whole length, from 

 its lower extremity to the sixteen miles distant and 13,800 feet 

 high pa?s of Malcha, whence another gbcier, that of the Zarrlala 

 river, descends on the north-eastern -lope for 2200 feet, by a 

 series of mighty icefalls. The paper is accompanied with a 

 pretty map which shows this grand ice-world, where no less thnn 

 thirteen secondary glaciers are ceding the ice-stream of the 

 Zerafshan. We notice in this paper that formerly the Zeraf- 

 shan glacier descended far lower than now. M. Mrushke'off 

 says that thirty-three miles below its actual extremity, namely, at 

 the village L^iaminor, there is a beautiful terminal-moraine which 

 crosses the valley and unites with three longitudinal moraines. 

 Immense boulders, thirty-five and forty feet in diameter, and 

 consisting of granite, syenite, and gabbro, cover the whole space 

 between the«e old moraines and the actual ones, so that there 

 cannot be the least doubt as to the glacier having descended 



for at least thirty-three miles lower than now. But when we see 

 how the composition of the drift changes lower down in the 

 valley, the loess, which is the wealth of the inhabitants in the 

 lower countries, changing into mighty conglomerates with im- 

 mense boulders, we are much inclined to think, that the former 

 glaciers descended yet far lower. Therefore we observe with 

 some regret that M. Moushketoff gives too little attention to 

 the diluvial formations of the Upper Zerafshan and to their 

 relations to the loess. 



GEOGRAPHICAL NOTES 



Whfn Humboldt determined for the first time the average 

 heights of continents, he could not, because of the want of data, 

 determine that of Africa. Now Dr. Chavanne publishes, in the 

 Procei'iiitigs of the Geogi-aphical Society of Vienna (vol. xxiv.), 

 an elaborate paper on this subject, accompanied with a hypso- 

 metrical map of the African continent, which is basid on no less 

 than 8000 hypsometrical mea'urements. After a thorough dis- 

 cussion of the relative value of various measurements. Dr. 

 Chav.inne discusses the average heights of separate parts of 

 Africa, and by how much each of them would raise the continent 

 if its mass were distribut- d over the whole of the surface of 

 Africa. He finds that the Atlas Mountains, if distributed over 

 the surface of Africa, would produce an elevation of 26 metres ; 

 the Sahara, 122 metres ; the plateaux of Soudan, 85 metres ; 

 those of Central and South Africa, 129 metres ; and so on ; and 

 he accepts for the average height of the whole of the continent 

 no less than 661 -S metres (with a probable error of ± 21 metres), 

 which figiu-e he considers to be rather below the truth. This 

 very high figure obvituslyis the result of the very great extension 

 of high plateaux, which we do not find to such an extent even in 

 Asia. 



In the Annual Report of the Surveyor General of India, which, 

 though it has been printed for months, has only just been allowed 

 to appear, prominence is given, under the heading of Trans-Fron- 

 tier Exploration, to an attempt to determine the positirn of the 

 head-waters of the Irrawaddy by Capt. J. E. Sandeman, through 

 the agency of a native surveyor whom he had ti-ained in imita- 

 tion of the late Col. T. G. Montgomerie's renowned staff in 

 India. This surveyor alleges that he ascended the river to Mo- 

 Sung-poon, near the point where it divides into two great 

 branches, the Malee and Mehka. The surveyor, we believe, 

 gives as an explanation of his not having prosecuted his journey 

 to a more successful termination, that he was attacked and 

 robbed by wild tribes ; but we hear privately that persons in 

 Burma, well qualified to form an opini'-n, attach little credit to 

 any of the surveyor's statements, and we fear, therefore, that 

 the position of the head-waters of the Irrawaddy is still an 

 un olved problem. 



Ttie Geographical Society of the Pacific is the title of a new 

 Society firmed at San Francisco. The Secretary is C. Mitchell 

 Grant, F.U.G.S. The objects of the Society, it is s'ated, are 

 to encourage geographical exploration and discovery ; to investi- 

 gate and dis-eminate geograi hical information by discussion, 

 lectures, and publications ; to establish in the chief city of the 

 Pacific States, for the benefit of commerce, navigation, and the 

 industrial and material intere-ts of the Pacific Slope, a place 

 where the means will be afforded of obtaining accurate informa- 

 tion, not only of the countries bordering on the Pacific Ocean, 

 but of every part of the habitable globe ; to accumulate a library 

 of the best books on gee-igraphy, history, and statistics ; to make 

 a collecMon of ihe most recent maps and charts, especially those 

 which relate to the Pacific coasts, the islands of the P.acific, and 

 the Pacific Ocean ; and to ei ter into correspondence v ith scien- 

 tific .and learned s-icieties whose objects include or sympathise 

 with geography. The Society will publi-h a BuUeiin and an 

 annual Journal. 



We learn from the Annual Report for 1880-1S81 of the 

 Swiss correspondent of the Geographical .Society of Vienna 

 that the following ge. detical and geological work was d^ne in 

 Switzerland :— The Geodetical Commission has published the 

 -eventh fascicule of the " Nivellement de Precision de la 

 Suisse," which contains the measurements done during the years 

 1877 to 1879 on the lines of Monte Cenero to Chiasso, Reichenau 

 to Sargans ai d Andermatt, and Siiss to Landquart and Chia- 

 venna, uniting thus the Swiss measurements with the Italian 

 ones. The Geological Commission publishes the fourth volume 

 of its new series, containing the important work, by Dr. Balzer, 



