276 



NATURE 



\_Aug. I, 1S72 



on both crystals. The cube faces are all striated in the direction 

 of the diagonals of the faces of the cube, and show, conseiiuently, 

 the tendency toward tlie octahedral form. The spinel was jier- 

 feetly transparent, of a beautiful ruby colour. Its form w.is that 

 of a hemitrope octahedron. —Prof 1). S. Martin exhibited speci- 

 mens of a clay containinjj recent shells, from a deposit which 

 had been the bed of a lagoon within quite a modern period, near 

 the town of Lewes, Delaware. The shells are in very perfect preser- 

 vation, though the epidermis is nearly gone, and the te.\ture is 

 becomnig fragile and chalky. The principal species are Saii- 

 •riihii'/iirii! fusca, Nassa obsohia, and Alodiola plicatuhi, of which 

 the first two are now living on the beaches outside, and proli.ibly 

 the last also. These specimens give an excellent illuslratiou of 

 the mode of formation of many of our fossiliferous clays and 

 marls. The deposit may, perhaps, h.ave value as a fertiliser. 

 He also gave some description of the very remarkable sand- 

 dunes or moving hills at Cape Henlopen, a mile or two east of 

 Lewes. The sand brought down by the Delaware River ac- 

 cumulates at this point, and when thrown up on the beach, is 

 taken in charge by the heavy east winds, and carried inland in a 

 great Hne of drifting hills, which rises in a very long and gentle 

 slope on the windward side, and falls off abruptly from the crest 

 on the leeward, as is usual in wind drifts. The whole surface of 

 the windward side is studded with the tops of dead tree trunks, 

 the remnants of a pine forest, overwhelmed by the advance of the 

 hill. The crest seems steadily approaching the lighthouse 

 keeper's dwelling, and will, probably, necessitate its removal in 

 the course of some few years. Prof. A. M. Edwards said the 

 specimens just exhibited are of considerable interest, as they show 

 very nicely the mode in which certain stratified rocks containing 

 fossils are evidently formed. Under certain circumstances, say 

 when formed in a locality like the tropics, where animal lile 

 abounded, and the moUusca especially occurred in large qu.i.ni- 

 ties, so that calcareous matter would accumulate, such a deposit 

 might b;come, in time, converted into a limestone in which the 

 forms of the enclosed shells and other organic remains '.vould be 

 preserved in a more or less perfect manner. If, on the otln-r 

 hand, calcium compounds were not present in abundance, but 

 the particles of the deposit thro^vn down should consist of coarse 

 and for the most part siliceous sand, sandstone, also enclosing 

 fossils, would eventuate. But to me, the material of which the 

 deposit exhibited consists, and which encloses the well-preserved 

 remains of moUusca, is of more special interest, as this is the 

 third time that such a formation has come under ray observation, 

 and I have studied one of these deposits with some care, as it 

 proved to be, for the most pai t, m.ade up of the siliceous skeletons 

 of DiatomaccLV, to theconsideration of which, both recent andfossil, 

 1 have devoted many years. All cases of marsh inversion are of in- 

 terest to geologists, and the opportunities they present the microsco- 

 pists of obtaining specimens for study makes themdoublyattractive. 

 The Ilobokenandthe Cape Henlopen specimens will be examined 

 and reported upon hereafter. — Mr. Jas. Hyatt made some re- 

 marks on the occurrence of some plants in the vicinity of New 

 York city. The cotton thistle, Onoponlon, may be found at Fish- 

 kill Landing, on the Hudson River, a short distance from the 

 railroad station, at the office of the iron works. He was able to 

 secure flowers there for Dr. Torrey's collection. The plant has 

 maintained itself there for several ye.\rs. Gciitiaiia <]Hiiiqu<:jiora 

 abounds in South-F.astern Duchess County, and from thence 

 he was able to furnish for Dr. Torrey's collection the only speci- 

 mens from this State . f 'tola ro/iindifo/ia abounds at Weehawken, 

 N.J., at the foot of the Palisades, west of the Ferry dock. 

 Paris 

 Academy of Sciences, July 15. — M. de Pambour presented 

 a further note on the reaction water wheel. — ."Vn import mt 

 memoir by MM. Jamin and Richard on the cooling of gases was 

 read. — M. A. Thenard described an apparatus for subjecting 

 gases and vapours to the action of electricity. — M. Gaiffe de- 

 scribed a new and cheap form of battery, consisting of a vessel 

 in which are immersed a rod of lead and a rod of zinc, the former 

 reaching the bottom, which is covered with a layer of aluminium; 

 the exciting fluid in water containing 10 per cent of hydrochlorate 

 of ammonia. — M. II. Sainte-Claire Deville communicated a note 

 by M. J. M. Gaugain on the induction currents developed in 

 M. Gramme's machine. — M. Faye presented a note by M. 

 Respighi in reply to some criticisms of F'ather Secchi, upon his 

 observations on the constitution of the sun. — M. J. A. Broun 

 read a second note on the simultaneity of barometric variations 

 between the tropics. — M. H. Tarry presented a note on the 

 magnetic [currents and solar explosions, which accompanied an 



aurora borealis observed on July 7. Upon this paper MM. C. 

 .Sainte-Claire Deville and Tisiot m,ade some remark-. — M. C. 

 Sainte-Claire UeviUe also presented a note by M. J. Gay, de- 

 scribing cloud-shadows observed by him at the Grande Char- 

 treuse, with reference to a recent balloon observation by M. Tis- 

 sandier. — M. H. .Sainte-Claire Deville communicited a note by 

 M. A. Houzeau on the instantaneous oxidation of alcohol, in 

 which the author described the conversion of alco'iol into acetic 

 acid and aldehyde by the direct action of ozomseil oxygen. — M. C. 

 Bernard presented a note by M. -V. (ire nut o'l th ■ '[uanlitafive 

 determination of urea bv means' of .Millou's tes' and the 

 mercurial pump. — M. C Dircste co.nmunicated his discovery 

 of tlie presence of starc'i in the young of the European fresh- 

 water tortoise ( T. ciiropica). — M. Des Cloizeaux read a further note 

 upon amblygonite and montebrasite. — M. Daubrce reported upon 

 a collection of minerals from Chili, offered by M. Domeyko to 

 the School of Mines at Paris. — M. Sainte-Claire Deville read a 

 paper on the absence of Combustible Gases in the enranations 

 from the Caldeira of Furnas in St. Michael's. The same gentle- 

 man communicated an extract from a letter by M. H. de Saussure, 

 giving an account of his observations upon the late eruption of 

 Vesuvius m April 111 Ihe present ye.ar, and made some remaiks 

 upon its contents. He also presented a n >te by M. Gorceix on 

 the state of Vesuvius, and of the gaseous emanations of the 

 Phlegn-ean fields iri the month of June, 1869. — M. Milne 

 lidwards presented a note by M. Wetelet upon the genus OvuUtcs, 

 which ths author regards as belonging to the Polyzoa. He 

 descidies a new form under the name of Ojitiiba luar^at'ilula. 

 iM. Milne Edwards also coinmanicated a note by M.\I. A. 

 Grandidier and L. Vaillant on the fossil crocodde of Amboulint- 

 sitre in .Madagascar, which they regard as a new species, and 

 name Crocodiiits robustus. 



BOOKS RECEIVFD 



J. Fayrer (J. and A. Chuicliill). 



us. translated l)y A. Vacfier, Stll 

 renewed, 1872 : R. T. Fairlie 

 ng wtiat one sees : Lieut. W. 



mnsculus in the possession of 

 at. Hist. : T. Dwiglit (Boston Soc. Nat. Hist.). -Embryo. 

 He.xapodous Insects : A. S. Packard, jun. (Peal)ody 

 :e) 



Plfan^en Ga'iziens u. der Bukowina ; J. A. ICnapp. — 

 and Norgate).— Revue d'Anthropologie, 1S72, No. 1.— 

 ogie, 8 Band 2 Heft. — Ueber algenartige Eiascfiliisse in 

 . iiber Bildung derselben ; Dr. Goppert. 



English.— The Thanatophidia of !ndi 

 — (iaaliiative Analysis by Dr. C. R. Pre: 

 edition (Churchill).— The Battle of the Gauges 



I (E. Wilson).— Perspective, or the Art of Draw 



j H. Collins (Longmans). 



American. — Description of the Balisnopti 

 the Boston Soc. N, ■- --■•-- 



I logical Stiulies on 

 Academy of Scieni 



1 Foreign.- Die 



\ (Through Williams 



i Zeitschrift der Biol 



CONTENTS Pack 



Dr. Livingstone 257 



Nicholson's Introduction to Biology 258 



Our Book Shelf 239 



Lbttkrs to the Editor: — 



Atmospheric Effect.— Prof. J. Tvndall, F.R.S -'to 



Spectrum of Aurora — G. H. Pringle 260 



Kinetic Energy —Prof. J. D. Everett 260 



Bree on Darwinism.— Dr. C. M. Bree, F.Z.S 260 



Volcanoes and Earthqualces. — J. Y. Buchanan 260 



On the Cohesion of Figures of Creosote, Carbolic and Cresylic 



Acids.— C. ToMLiKSON, F.R.S. 261 



Hereditary Instinct. — L. Hurt 261 



Recent Observations IN THE Bermudas. By J.^Matthew Jones 2^2 

 Spontaneous Appearance of Exotic Forage Plants in France 



after the late War 263 



The Huron Race and its Head Form 264 



Conductivity of Mercury. By Capt. J. Ericsson. (With Illus- 



trations ) 265 



Notes 2'iB 



Professor Agassiz's South American Expedition. — HI. . . . 270 



Anatomy — The Placenta of the "Tamandua" Ant-eater 273 



Meteorology. — On a Meteoric'Iron lately found in El Dorado County, 



California . . . . 27J 



Scientific Serials 273 



Societies and Academies 274 



Books Received 276 



j NOTICE 



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