Dec. 14, 1 8 76 J 



NATURE 



151 



local group of carps, termed " Hill Barbels, or SchizotkoracincB," 

 by McClelland : that this group is almost restricted to cold and 

 elevated regions, spreading to the most eastern portion of 

 Western Turkestan, Afghanistan, and along the western slopes 

 of the Himalayas to China ; and that these forms are entirely 

 distinct from the carps of the plains to the south of the Hima- 

 layas. — A communication was read from Mr, Martin Jacoby 

 giving the descriptions of new genera and species of Phytophagous 

 Coleoptera. — A communication was read from Dr. A. Giinther, 

 F. R. S., containing the description of a new species of lizard from 

 Asia Minor, which he proposed to name Zootoca danfordi after 

 Mr. C. G. Danford, its discoverer. — Dr. Giinther communicated 

 a paper by Mr. W. Ferguson, of Colombo, containing the 

 description of a new species of snake of the genus Afpidura 

 from Ceylon, for which the name of A. guentheri was proposed. 



Geological Society, November 22. — Prof P. Martin Dun- 

 can, F, R.S., president, in the chair. — The following communi- 

 cations were read : — ^On the pre-Cambrian (or Dimetian) rocks 

 of St. David's, by Henry Hicks, F.G.S. Referring to the ridge 

 of pre-Cambrian rocks, which he described in a former paper as 

 running down the St. David's promontory, and as previously 

 supposed to consist of intrusive syenite and felstone, the author 

 • stated that he had now found it to be composed exclusively of 

 altered sedimentary rocks of earlier date than the Cambrian 

 deposits, the conglomerates at the base of which are chiefly made 

 up of pebbles derived from these rocks. Recent investigations 

 had led him to the conclusion that the main ridge was composed 

 of two distinct and decidedly unconformable formations, the 

 older of which, composed of quartzites and altered shales and 

 limestones, constituting the centre of the ridge, has a north-west 

 and south-east strike, and dips at a very high angle ; whilst 

 the newer series, consisting of altered shales, and having at its 

 base a conglomerate composed of pebbles of the older rock, has 

 a strike nearly at right angles to that of the latter. For the 

 former he proposed the name of Dimetian, and for the latter 

 that of Pebidian. The author indicated the points of resem- 

 blance between these pre-Cambrian rocks and the Laurentian of 

 Canada, the Malvern rocks, and others in Scotland and else- 

 where, but thought it safer at present to abstain from attempting 

 any definite correlation of them. The exposure of the older, or 

 Dimetian series, led the author to ascribe to those rocks a thick- 

 nesss of at least 15,000 feet ; the upper, or Pebidian rocks, 

 which *^ank both sides of the old ridge through a great portion of 

 its length, are apparently of considerably less thickness, but they 

 are in most parts more or less concealed by Cambrian deposits 

 overlying them unconformably. Running nearly parallel with 

 Ramsey Sound is another large mass of the author's Pebidian 

 rocks, and at the south-western extremity of Ramsay Island they 

 compose a bold hill almost 400 feet high, and on the east side of 

 this a fault, with a downthrow of at least 14,000 feet, has brought 

 the Arenig beds into contact with the pre-Cambrian rocks.— On 

 the fossil vertebrates of Spain, by Prof. Salvador Calderon, com- 

 municated by the President. 



Anthropological Institute, November 28.— Col. A. Lane 

 Fox, F.R.S., president, in the chair — An Indian hammock from 

 the city of Mexico, weapons from Perak and British Guiana and 

 a Bosjesman's skull were exhibited. — The President, by permis- 

 sion of Messrs. Bollin and Feuardent, exhibited some terra cotta 

 figures from Tanagra, Bceotia, and read some notes thereon. 

 Mr. Hyde Clarke and others joined in the discussion. — Papers 

 on the Lapplanders, by A. von Humboldt von Horck, and on the 

 tribes of British Guiana, by the Rev. D. Harper, were also 

 read. 



Royal Microscopical Society, December 6.— H. C. Sorby, 

 F.R.S., president, in the chair.— The President exhibited a fac- 

 simile of Jancen's microscope, made by permission of the Dutch 

 Government from the original, exhibited at the South Kensington 

 Loan Collection. — A paper by the Rev. W. H. Dallinger was 

 read by the Secretary, on Navicula crassinervis, N. rhomboides 

 and Frustulia saxomca, as test objects, in which, after referring 

 at some length to the recent discussion upon the subject of their 

 identity or difference, he expressed his belief that they were all 

 specimens of Rhomboides, differing only as to size ; and in support 

 of his opinion, a number of very beautifully executed drawings were 

 exhibited to the meetmg, showing the microscopical appearance 

 of the diatoms in question under a magnifying power of 800 

 diameters. 



Institution of Civil Engineers, November 28. — Mr. 

 George Robert Stephenson, president, in the chair. — The paper 

 read was on the chalk water system, by Mr. J. Lucas. 



Cambridge 



Philosophical Society, November 20. — Mr. O. Fisher 

 read a communication on the effect of convective currents 

 on the distribution of heat in a bore-hole. This paper was sup- 

 plementary to one read by the author on November 29, 1875, 

 The temperatures obtained in the boring at Speremberg, near 

 Berlin, which attained a depth of upwards of 4,000 feet, were 

 reduced to a mean law by Prof. Mohr, of Bonn, and had been 

 already shown by the author to conform closely to those ex- 

 pressed by a parabolic curve, having its axis horizontal, and its 

 vertex at a depth of 5, 171 feet expressed by the equation — 



V— — ?^i jr' + 0'Oi2Q82.xr+7'i8i7. 



|q8 ' " 



V being the temperature expressed in Reaumur's scale, and Jtrthe 

 depth. An elaborate account of the observations taken in the 

 Speremberg boring has been given by Dunker in a paper en- 

 titled " Ueber die Benutzung tiefer Bohrlocher zur Ermittelung 

 der Temperatur des Erdkorpers, und die desshalb in dem Bohr- 

 loche zu Speremberg auf Steinsalz angestellten Beobachtungen. " 

 The temperature curve within the earth's crust being believed to 

 be a straight line expressing an increase of 1° Fahr. for 60 feet 

 of descent, it was shown that the departure from this law in a 

 large bore-hole (in the present case a foot in diameter) might be 

 accounted for by vertical currents. At the surface of the water 

 its temperature, from radiation and evaporation, will nearly 

 coincide with that of the upper bed of rock. As we descend, 

 the tendency will be for the currents to warm the water in the 

 upper part of the bore-hole above the normal temperature of the 

 rock, and to cool it in the lower part below the temperature of 

 the rock. At a certain depth the temperatures of the water and 

 rock would be the same. By Dunker's table this appears to 

 have occurred at the depth of about 200 feet. A diagram re- 

 presenting graphically the effects mentioned will appear, accom- 

 panied by the proper explanations, in the forthcoming number 

 of the Sozxtiy^s Proceedings. — Prof. Hughes then gave a criticism 

 of the evidence for pre-glacial man, which we have already 

 noted. 



Manchester 



Literary and Philosophical Society, October 31. — Rev. 

 William Gaskell, M. A., in the chair. — Remarks on the general 

 affections of the barometer noticed by Mr. J. A. Broun, by 

 Prof. B. Stewart, LL.D., F.R.S. Mr. J. A. Broun has found 

 as an experimental fact that simultaneous variations of the baro- 

 metric pressure occur at such distant portions of the globe as to 

 lead to the inference that the whole globe is thus affected, from 

 which Mr. Broun infers that some other force besides gravity is 

 concerned in these phenomena. We know as a matter of fact 

 that there are causes at work which give rise to electrical separa- 

 tion, although we may not know the precise nature of these 

 causes. Thus evaporation goes on from the surface of the sea 

 and of the land. Changes take place in the amount of aqueous 

 vapour held by the air, and also probably in the molecular state 

 of this aqueous vapour. But although we may not be able to 

 point to the specific actions which produce electrical separation, 

 we know that such separation implies a one-sidedness or hetero- 

 geneity ; and since gravity will presumably act differently on 

 the two things, we may probably suppose that one of the con- 

 stituents which have caused this electrical separation may have a 

 tendency to mount upwards in the atmosphere, while the other 

 may have a tendency to move downwards. For instance, it 

 evaporation from the surface of the earth or sea be one cause of 

 this electrical separation, we might imagine the land or sea to 

 become electrified in one way, while the vapour electrified in the 

 other direction might mount in the air, owing to its being speci- 

 fically lighter. In fine, whatever be the cause of the electrical 

 separation, we may presumably suppose that the one constituent 

 will either remain below or find its way downwards, while the 

 other, carrying with it its peculiar electricity, will mount up- 

 wards. Now, may not the earth be regarded as a Leyden jar, 

 the sea and earth forming one coating, and the upper, rarer, and 

 hence electrically conducting strata of air forming the other 

 coating ; and will not the tendency of the action above named 

 be to charge the upper coating with one kind of electricity and 

 the under with another? Such a process would, of course, be 

 continually going on, while on the other hand the earth, regarded 

 as a Leyden jar, would, by means of thunderstorms, and possibly 

 by other means, be continually discharging itself. Next, let us 

 suppose that by some extensive local circumstances a greater 

 than usual electrical separation and charging of the earth jar has 



