Dec. lo, 1874] 



NATURE 



119 



foreif^ material filling the fisiure rtflcctinjj light less perfectly 

 than the general surface of the berj;. I conceive that the up[;er 

 ■surface of one of these great tal>ular soulhc-rn iccbergii, inclu<ling 

 by far the greater part of its l;ulk, an'i culminating in the portion 

 expofcd above the turfacc of the Fca, was formed by the piling 

 up of successive layers of snow during the jK-riod, amounting 

 perhaps to several centuries, during which the ice-cap was 

 slowly forcirg ibelf over the low land and out lo sea over a long 

 extent of gentle slope, until it reached adepth considerably alxjve 

 200 fathom's, when the lower epecific weight of the ice cau»e<l 

 an upward strain which at length overcame the cohesion of the 

 mass, and ]»ortions were rent off and floated away. If this l>c 

 the true history of the formation of these icebergs, the absence 

 of all land dcLris in the portion exposed above the surface of the 

 tea is readily umierttood. If any such exist, it must be confined 

 to the lower part of the berg, co that part which hax at one time 

 or other moved on the fl'iorof the ice-cap. 



The icebergs, when they are first disjjersed, float in from 200 

 lo 250 fathoms. When, therefore, ihey have been drifted to 

 latitudes of 65'' or 64" S., the Iwltom of the Ijcrg just reachcn the 

 layer at which the temperature of the water is distinctly rising, 

 and it Ls rapiilly melted, and the murl and pebbles with which it 

 is more or less charged are precijjitated. That this precipitation 

 takes place all over the area where the iccl^rgs are breaking up 

 constantly, and to a considerable extent, is evident from the fact 

 of the soundings being entirely composerl of such deposits ; for 

 the diatoms, Globigtrinx-, and radiolarians are present on the 

 surface in large numbers ; and unless the deposit from the ice 

 were abundant it would soon be covered and masked by a layer 

 of the exuviae of surface organisms. 



SCIENTIFIC SERIALS 



Po^'i;t>iJor/I'i Annalen dir Phyuk und C/itmie, No, 6. — 

 The first paper, by G. Lund'juist, On the reflection of light 

 from the outsirle of isotropic bodies, is reprinted from the 

 "Transactions" of the Royal Society of Upsala. — Dr. H. 

 Brougersma contril>ule» a memoir On the .Medium in electrical 

 influence, in which, following up the experiments of Kiess, he 

 examines Faraday's theory ol electrical induction by polarisation 

 of the medium, and describes in detail the apparatus with which 

 be cx)«rimenle<), tabulates his results, and agrees with Riess's 

 induction as' to a direct influx of electricity.— The next article 

 comprises a series of communications from the .Mineralogi- 

 cal Institute of the University of Strasburg, in which I'aul 

 Groth treats of the crystalline form and thermo-electric 

 properties of smaltine or arsenical cobalt. Its chemical 

 f'/rinula is very variable, R = (Co, Ni, Fe) A»,, Kight 

 .!cs from different localities, which contribute a better 

 • ledge of the hemihedral forms of the species, are dis- 

 ■<\. He concludes that some of the forms hitherto re- 

 gaidci as holohcdral are hemihedral forms with parallel tides. 

 As with iron pyrites and col/alt-glancc, with which it is isomor- 

 phous, orepart of the crystal is negative towards cojjper, while the 

 other half is positive. — L)r. Hintze treats of the chemical compo- 

 lition of leadhilliic. Prof, Laspeyres two years ago de5crit.ied 

 a mineral from Iglesias, in Sardinia, under the name of maxite, 

 of which the formula was sl'bSO^ -^ gl'bCO, + 41'bO + 5H/J. 

 M. IJertrand, of Paris, ffion after published an account ol lead- 

 billite from the sameneighb<jurho'xl. The author prove* that the 

 two minerals are identical, and that the formula r^fleadhillite is not 

 PbSO, + 3Pl<CO;,3s hitht-rto believed, but 2pbS04-t•4PbCfJJ-^ 

 V^/> + 2l1.'). the next paper, by the same author, is cryttal- 

 ' ; on the combination of aldehyde wiili the 

 IS. The chemical composition and crystal- 

 :, of ditolyltrichloraeihan, diphenyltribroma- 

 Moraethylen, diphenyldibromactljan, dimo- 

 raethan, &c. All ihete bodies belong to 

 n. — Dr. A, Arzruni gives a short note on 

 iv. 1- rnite. The next (oapcr by the same author 



is " ' '-s on the turpentinoelhydrales," which he 



foil' ; raphic and optical researches on compounds 



of ui'; .. ..i;L parer is on two isomorjohous substances 

 derive'] from ioenzol. — F. Zollner prints his important paper on 

 the a(igrCi;ation and position of the £un-iix*ts, and concludes that 

 they are cxAt'i >conaccous products. — Dr. Karl liraun contri- 

 butes .-.tudie^* m the earth's magnetism. — Among the reprinted 

 pa(>er» are Dr. Andrews' on ozone and Prof. Wright's on the 

 ix.irrl.atir.n of the zodiacal light. 



Memorie dtlla .Socula Sp^ltrouopisli fudiani, SeptemlMsr 1874 

 — This numloer contains a paper by .Mr. J. yi. Ixockyer, d'scrlb- 

 irij; certain phenomena seen when examining the spectrum of the 

 electric light through a m.-Jss of sodiim vapour in a tube. \Vh(m 

 ihi , is done, the wjdiurn lines are feen to ' haile gra/lually off, 

 sometimes on one side, sometimes on both, the boundary of the 

 shading being curverl ami sometimc-s limited by a bright line. — 

 '1 liere is also another |>aper by the same author, f Jn experimentti 

 on the absorption of a great thickness of sodium and iodine 

 vapour in a tul«: 5 fL long. After mentioning that it had been 

 hitherto assumed that a great thickness of gas causes its radia- 

 tion, and therefore its al/s'orption, to beome nujrc continuous, 

 he slates that, on generalising his work, it appears that when the 

 density of a vapoui is increascl, a ontinuous »[oectrum is 

 approached in the case of the metallic elcment.s of low specific 

 gravity by the widening of their lines, and in that of (hr elements 

 of high sp. gr. by ihe increase of the number of lines. To test 

 thi't, the absorption of sodium vapourin a 5 ft. tubr: wasoloserverl, 

 and the U line was found to loe no thicker than the same line pro- 

 duc'd by a test-tube full of the vapour, and the line was thicker 

 than the D-line in the solar spectrum, in which spectrum all the 

 short lines are reversed. -lather .Secchi communicates a k-tter of 

 A. 'I . Arcimis. detailing oiwervations on the spectra of meteorites. 

 'I lie spectra 'jf all seem to loe Cjntinurous, Imt wanting in the 

 violet, that colour of the spectrum predominating according to its 

 colour to the naked eye. The sodium line was visdole in the trail 

 of ■/>me, as also were the lines of maf^iesium. — G. iJe Sisa 

 gives a tabic of the S'olar spots observed at Palermo from June to 

 September. — A table of the chromrosphere, as seen during 

 1- el/ruary and March last at Palermo, is added to this numbw, — 

 E. 1-ergoJa contributes a lengthy paper on the position of the 

 axix of rotation of the earth with respect to its axis of figure. 



SOCIETIES AND ACADEMIES 

 London 

 Linnean Society, Dec. 3.— Dr. G. J. Allman, K.R.S., 

 pre)ident,in the chair. — Mr. Jas. lirogdt-n, Sir Edmund liuckley, 

 liart., .M.P,, Messrs. Jas. Cowherd, P. Dufly, C. C. Dupre, A. M. 

 Ross, and J. W. Silver were severally elected Fellows of Ihe 

 Society.— Prof. Iluxlcy read a paper On the classification of tlic 

 animal kingdom, which will be found in another column. An 

 interesting discioAsion followed, in which the President, Mr. Busk, 

 Mr. II. G. Seeley, .Mr. Stewart, Dr. .Murie, and others fook part. 



Chemical Society, Dec. 3— Mr. W. II. Perkins, F.R.S., 

 in the ch.iir.— A paper was read by Mr. S. Lupton On the formula.- 

 of the alums ; the next was a notice On the colour of cupric 

 chloride, by Mr. W. N. Hartley, who finds that the crystals of 

 the salt when quite dry have a blue colour, and not a green, as 

 they usually appear when slightly moist.— Papers were also read 

 On the oxidation of the essential oils. Part II. by Mr. C. T, 

 Kingzett; On the purification and boiling-point of methjl 

 hezyl carbinol, by Mr. li. Neison ; and a note on the boiling- 

 poii.t of methyl hexyl carbinol, by Dr. C. .Schorlemmcr, F.K.S. 



Zoological Society, Dec. i.— Dr. A. GUnther, F.R.S., in the 

 chiir.— A letter was read from the Rev. S. J. Whitmee, of 

 Samoa, stating that he had sent home for the Society some birds 

 and a pairof the Samoan Hat, which had lately been descriloed by 

 .Mr. .\\*».om» Plerojnis wliitmeei. Particulars were given as to 

 the habiu of the latter. -A communication was read from Mr. 

 Henry W. Piers, of Capetown, containing remarks on wonie 



specimens of Gymnelrus in the museum at Capetown. The 



Secretary announced that CoL R. S. Tickell, late of H..m! 

 Indian Army, had presented lo the Society's librarya very finely 

 illustrated MS. work, in seven small folio volumes, on the Orni- 

 thology of India. — A communication was read from .Mr. J. 

 lirazi.;r, of Sydney, N.S.W., giving descriptions fof eleven new 

 spetic-s of terrestrial and marine shells from North-east Aus- 

 tralia.— A paper, by Messrs. P. L. Sclatcr and O. Salvin, was 

 rca/1 on birds collected by Mr. Whitely in Western Peru, being 

 the eighth communication made by the authors on this subject. 

 — \ communication was read from Mr. M. Whitely, containing 

 some further notes on Humming Birds Collected by him in High 

 Peru. — Mr. A. G. liutler read a pajocr in which Iw: gave descrip- 

 tions of three new species of homopterous insecU from various 

 [/arts of the world.— Mr. A. H. Garrod gave Wome further joar- 

 ticulars on the mechanism of the "shcv,- off" in the Bustards, 

 and described the peculiar structure of \.\ie/renum liiii;uii recently 

 noticed in 3 young male of the Great Bustard. 



