530 



NATURE 



[March 28, 1901 



Geological Society, March 6.— J. J. H. Teall, V.P.R.S., 

 president, in the chair.— Recent geological changes in Northern 

 and Central Asia, by Prof. George Fredericl< Wright. The 

 present paper is the outcome of a journey made by. the author 

 in company with Mr. Frederick B. Wright in 1900-1901. In 

 North America an area of about 4,000,000 square miles was 

 brought under the direct influence of Glacial ice during the 

 Glacial epoch. The result of six weeks spent in Japan was to 

 show that there are no signs of teneral glaciation in Nippon or 

 Yesso. Neither is there any sign of glaciation along the border 

 of the Mongolian Plateau, where the general elevation is 5000 

 feet, but the whole region is covered with loess. This has 

 usually accumulated like immense snow-drifts on the south- 

 eastern or lee-side of the mountains, and in it houses and 

 villages are excavated. In the mountainous region, strata of 

 gravel and pebbles are so frequent in the loess that it is neces- 

 sary to invoke both wind and water in order to explain fully 

 the origin of the deposit. At the present time the loess in the 

 interior is being washed away by streams much faster than it is 

 being deposited by the wind. The journey across Manchuria 

 from Port Arthur along the Lao-Ho and Sungari rivers was 

 through valleys choked with alluvium, and there was no evi- 

 dence that the drainage of the Amur had ever been reversed by 

 ice, like that of the St. Lawrence ; nor was there any other 

 evidence of glaciation. The lower course of the Amur indicates 

 subsidence. Again, there are no signs of glaciation on the 

 Vitim Plateau. Lake Baikal appears to be of recent origin ; it 

 is 4500 feet deep and has not been filled by the great quanti- 

 ties of sediment brought down by the Selenga and other rivers. 

 Although glaciers could frequently be seen on the mountains 

 which border the Central Asiatic Plateau to the north-west, 

 there was no evidence that the glaciers had ever deployed on 

 the plain. The loess-region of Turkestan, and indeed the whole 

 area from the Sea of Aral to the Black Sea, appears to have 

 been recently elevated, in some places as much as 3000 feet. 

 Desiccation took place at the same time, so that the larger 

 lakes are only brackish or still fresh. Direct evidence of this in 

 the form of deposits is given. The author thinks it likely that 

 the absence of glaciation in Northern Asia may have been due 

 to the rainlessness of the region, and that while America was 

 elevated, Asia was depressed during the Glacial Epoch. — The 

 hollow spherulites of the Yellowstone and Great Britain, by 

 John Parkinson. A recent journey to the National Pask of the 

 United States, resulting in a study of the obsidians and rhyolites 

 in the field and at home, suggested a direct comparison between 

 the hollow spherulites characteristic of these rocks and those of 

 the rhyolites of Shropshire, Jersey and elsewhere. Hypotheses 

 framed to account for the varying structures of spherulites are : 

 (i) Hollow spherulites are the result of some property of 

 the original magma, or (2) are due to the decomposition of 

 an originally solid spherulite by heated waters. Taking the 

 second alternative first, a description is given of the effect of 

 solfataric action on the rhyolites of the Yellowstone Canon. 

 The conclusion reached is ' ' that the action of hot waters 

 charged with silica may be to remove portions of the rock, or 

 to permeate it without destroying its characteristic structure ; 

 that we obtain, however, no evidence to show that the spheru- 

 lites are most easily attacked, but rather the reverse." Explana- 

 tion, therefore, is most naturally sought in some property of the 

 original magma, and that propounded by Prof. Iddings appears 

 the nearest in accord with facts. Exception is taken to certain 

 physical processes postulated by Prof. Iddings in a recent 

 memoir, but with his earlier work the present writer is substan- 

 tially in agreement. In the second part of the paper direct 

 comparison is drawn between the structures exhibited by the 

 hollow spherulites from Obsidian Cliff and those of examples 

 from Shropshire, Jersey and other localities. Taking into con- 

 sideration the resemblances between the hollow spherulites of 

 the Yellowstone region and those of Great Britain, the conclu- 

 sion is drawn that the hypothesis of corrosion is as inapplicable to 

 the latter as to the former. On the contrary, the author 

 believes that the cavities of the spherulites are the result of the 

 hydrous state of the magma. 



Royal Microscopical Society, February 20. — Mr. A. D. 

 Michael, vice-president, in the chair. — A photograph of Amphi- 

 pkura pellucida^ taken by Mr. Brewerton, was exhibited. — Mr. 

 Nelson said the photograph was interesting because it showed 

 the transverse stria; as thin in comparison with the spaces be- 

 tween them. Some optical theorists maintained that the strice 

 and spaces must be of equal width, whereas he had affirmed 



NO. 1639, VOL. 63] 



that the strise were much finer than the spaces. In many 

 photographs of this object they appeared to be of equal width, 

 but that was because the object had been badly photographed. 

 In the example before the meeting the photograph had been 

 properly taken, and therefore exhibited the difference in the 

 thickness of the lines and the inter-spaces. — Mr. Rogers brought 

 to the meeting a contrivance for exhibiting a fly in the act of 

 feeding. This differed in some respects from Mr. Macer's 

 arrangement for a like purpose, being a brass- plate, '^" x i", 

 underneath which a brass cone was soldered to contain the fly, 

 the plate lying on the stage of the microscope like an ordinary 

 slide. — Mr E. M. Nelson read a paper on the tube-length of 

 the microscope, explaining the difference between the mechanical 

 and optical tube-length, illustrating the subject with drawings 

 and formulae. — The chairman thought there was no subject con- 

 nected with thetechnique ofthe microscope about which ideas were 

 more vague than that of thetube-length ; many thought it was the 

 length of the brass tube. Although it had often been pointed 

 out in that room that what was really meant was the optical 

 tube-length, the subject did not seem to be very well under- 

 stood, very little practical information had been published 

 which would enable a person to ascertain the tube-length of his 

 microscope but Mr. Nelson had now given them a method by 

 which this could be found. — Mr. F. W. Millett's report on the 

 recent Foraminifera of the Malay Archipelago was taken as 

 read. — The chairman called attention to a set of slides of bac- 

 teria and blood parasites which were exhibited by Mr. Conrad 

 Beck. — Some mounted rotifers, sent from Natal by the Hon. 

 Thos. Kirkman, were also exhibited. 



Linnean Society, March 7.— Prof. S. H. Vines, F.R.S., 

 president, in the chair. —Mr. F. Enock showed a series of 

 lantern-slides illustrating the metamorphoses of a dragonfly, 

 ALschna coerulea, and gave an interesting account of the life- 

 history of that insect.— Mr. H. E. Smedley exhibited and made 

 remarks on a collection of models of fungi, Nepenthes, Sarra- 

 cenia and aroids, as also several models of sections of flowers, 

 in wax and composition. — Dr. J. Murie, on behalf of Mr. H. 

 Doubleday, exhibited an orange within an orange, the enclosed 

 fruit having a complete rind, in which respect it differed from 

 one previously shown by Dr. Rendle {Proc. Linn. Soc. 1890-91, 

 p. 7). — Mr. Alfred O. Walker read a paper entitled " Contri- 

 butions to the Malacostracan Fauna of the Mediterranean," in 

 which he gave the results of dredging operations carried on at 

 Cannes and Hyeres from an open boat, in depths not exceeding 

 35 fathoms and with the simplest apparatus. The number of 

 species obtained were as follows : — Podophthalmata, 10 ; 

 Schizopoda, 8, including a new species, Mysid»p$is serraticauda ; 

 Cumacea, 9; Pantopoda, i; and Amphipoda, 41, including 

 two new species, I eucothoe platydactyla and Melpkidipella sp., 

 with two others not previously recorded in the Mediterranean. — 

 Miss G. Lister's paper on the occurrence in Egypt of Tristicha 

 hypnoides, Spreng., communicated by Mr. Arthur Lister, 

 F.R.S., was read by the secretary, 



Entom logical Society, March 6. — The Rev. Canon 

 Fowler, president, in the chair. Mr. H. St. J. Doni?thorpe 

 exhibited a parasite or Brachonid on Cenihorkynchus sulcicollis, 

 bred from the galls in a turnip caused by the larva of that 

 beetle, together with the host, — Mr. A. J. Chitty exhibited a 

 variety of PsylHodes cyanoptera. 111., the coloration of the thorax 

 dark instead of the usual red, taken by him along with the 

 typical form in August 1892 at Wicken Fen.— Mr. H. J. 

 Turner exhibited a long series oi Bryophila muralis (g/andtfera) 

 from Dawlish. The whole were either taken on, or bred from 

 pupje cut out of, a single roadside wall some hundred yards 

 long, very lofty, and facing nearly north, on which aspect, how- 

 ever, it was protected by higher ground. They were obtained 

 in mid-August, with the exception of a few which emerged at 

 intervals during September and October 1900. Generally 

 speaking the 'specimens were very dark, and the series was 

 remarkable in that it contained but a few isolated examples of 

 the forms which are prevalent in more eastern localities like 

 Freshwater, Eastbourne or Folkestone. The hind wings of all 

 the specimens were dark, while in the majority the black 

 markings of the fore wings were much intensified and increased 

 in number, and a few specimens were largely suffused with 

 black. A considerable number showed a dark rich green 

 suffusion, while a large proportion were of a very deep yellow or 

 olive colour with black markings. The yellow forms were per- 

 fectly natural, as a number emerged from the pupa exactly of 

 that hue. Only a few showed any trace of the typical delicate 



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