2 8o 



NATURE 



\Fcb. 4, 1875 



appears to contain vevy little of the ^^■ater of the drop which 

 causes it. The actual size of these rings depends on the size 

 and speed of the drops. They steadily increase as they descend, 

 and before they stop they have generally attained a diameter of 

 from one to two inches, or even more. The cut on p. 279 shows 

 the effect which may be produced in a glass vessel. It is not 

 that the drop merely forces itself down under the surface, but in 

 descending carries down with it a mass of water which when the 

 ring is I inch in diameter would be an oblate spheroid having a 

 larger axis of 2 inches and a lesser of about i \ inches. For it 

 is well known that the vortex ring is merely the core of the 

 mass of lluid which accompanies it, the shape of which is much 

 the same as that which would be formed by winding string through 

 and through a curtain ring until it was full. It is probable that the 

 momentum of these rings corresponds very nearly with that of 

 the drops before impact, so that when rain is falling on to water 

 there is as much motion immediately beneath the surface as 

 above it, only the drops, so to speak, are much larger and their 

 motion is slower. Besides the splash, therefore, and suiface 

 effect which the drops produce, ihey cause the water at the sur- 

 face rapidly to change places with that at some distance below. 

 Such a transposition of water from one place to another must 

 tend to destroy wave motion. This may be seen as follows. 

 Imagine a layer of water adjacent to the surface and a few inches 

 thick to be flowing in any direction over the lower water, which 

 is to be supposed at rest. Tlie eflcct of a drop would be to knock 

 some of the moving water into that which is at rest, and a cor- 

 responding quantity of water would have to rise up into the 

 moving layer, so that the upper layer would lose its motion by 

 communicating it to the water below. Now, when the surface 

 of water is disturbed by waves, besides the vertical motion the 

 particles move backwards and forwards in a horizontal diiection, 

 and this motion diminishes as we proceed downwards from the 

 surface. Therefore in this case the eflect of rain-drops will be 

 the same as in the case considered above, namely, to convey the 

 motion which belongs to the water at the surface down into the 

 lower water where it has no effect so far as the waves are con- 

 cerned, and hence the rain would diminish the motion at the sur- 

 face, which is essential to the continuance of the waves, and thus 

 destroy the waves. — On the stone mining tools from Alderley 

 Edge, by Prof. W. Boyd Dawkins, F.R.S. — Archaic iron 

 mining tools from lead mines near Castleton, by Mr. Rooke 

 Pennington. 



Paris 

 Academy of Sciences, Jan. 25. — M. M. Fremy in the chair. 

 — The following papers were read: — On the decrease cf the 

 upper Doubs and the means to prevent it, by M. H. Resal. — On 

 the efl"tct produced by the application of armatures on magnets, 

 by lU. J. Jamin. — On the mineral substances contained in the juice 

 ot beet and the potash extracted from it, by M. E. Peligot. — On 

 the fertilisation of the genus Viohi, with special reference to Viola 

 tricclor /loflaais, by M. A. Trecul. — On the phosphorescence of 

 Marine Invertebrata, by M. de (luatrefages. — M. Daubree then 

 read a letter received from H. M. Don Pedro, Emperor of Brazil, 

 giving a description of an earthquake which took place on 

 Oct. 30 last in the province of St. Paul. — The same gentleman 

 then communicated a memoir by I\I. J. D. Dana, on the I'seudo- 

 moiphs of Serpentine and other minerals from the mine Tilly- 

 Foster, Putnam County, State of New York. — Researches on 

 albuminoid matter, by M. P. Schiitzenberger. — On the action of 

 electrolytic o.xygen on methylic alcohol, by M. A. Renard ; 

 experiments made in continuation of those described on Jan. 11 

 (see Nature, vol. xi. p. 240). The results were similar, pro- 

 ducing acetic acid, acetate of methyl, and methyl-sulphuric acid. 

 The formation of acetic acid from methylic alcohol is explained 

 by the formulfc — 



^[{3 I o + 2O = 2H2O + CO 



CO + "^"^ ) o - ^^^^^° \ o 



— On the flame of sulphur, and thedlffeient lights that can be 

 utilised in photography, by MM. A. Ri-ke and C. Bardy. The 

 authors examined eight dilferent flames, viz., the oxy-hydrogen 

 light, Drummond's lime-light, zinc burning in oxygen, the mag- 

 nesium flame, a current ol nitric oxide gas burning in a globe 

 containing bisulphide of carbon, a jet of nitric oxide gas on a test 

 containing bisulphide of carbon, a jet of oxygen on the same, 

 and a jet of oxygen on a test containing sulphur. The eight 

 lights showed their photographic power in the order mentioned, 

 the last being eight times as strong as the first. — After some 

 short mathematical notes, M. D. Lonlin read a paper on his 



improvements of dynamo-electric machines. — A note by M. 

 Lecareux, on the treatment of cholera. — A memoir by M. 

 Anninos, on the direction of aerostats. — MM. Hemmerich, 

 Bourquelot, Chaperon, Ileyduck, and Robinson then made some 

 communications on Phylloxera. The Minister for Ai;riculture 

 and Commerce has placed more funds at the disposal of the 

 Academy for the investigation of this subject. — A letter was then 

 read, dated Noumea, Nov. 4, 1S74, from MM. Andre and 

 Angot, announcing their successful installation for the observa- 

 tion of the Transit of Venus. — The Minister for Foreign Aft'airs 

 transmitted to the Academy documents received from the French 

 Consul at Manilla, with reference to the same subject, and 

 announcing the forwarding of ten photographic proofs taken 

 during the transit. — A letter on the same subject from M. Heraud, 

 dated Saigon, Dec. 18, giving a complete description of the obser- 

 vations and their results. — A letter from Mr. J. Norman Lockyer, 

 describing the preparations for the expedition sent by the Royal 

 Society of London to observe the total eclipse of the sun. The 

 observations will be mainly confined to the spectra of the chro- 

 mosphere and the coronal atmosphere, with the principal 

 view to determine the chemical constitution of the latter. — On 

 elimination ; calculation of Sturm's functions by determi- 

 nants, by M. Lemonnier. — A note on the partition of numbers, 

 by Mr. Glaisher. — A note on the theory of surfaces, by M. Hal- 

 phen. — On a formula of transformation of elliptic functions, by 

 M. J. Brioschi. — A note by M. T. Schloesing, on atmospheric 

 ammonia. — On the presence of copper in the organism, by MM. 

 Bergeron and L'Hote. — On the general phenomena of the eni- 

 bryugeny of Nemertida, by M. J. Barrois. M. de Quatiefages 

 then made a few remarks on this paper. — On the organs of touch 

 in mm, by M. Jobett. — On the invasion of grasshoppers in 

 .Algeria (April — August, 1874), by M. Brocard. — On the electro- 

 chemical resistance of aluminium when employed as a positive 

 electrode of a voltameter, by M. Ducretet. — M. Chapelas then 

 gave an account of barometrical observations he made in Paris 

 during the gale on Jan. 2r. — M. Mangot read a note on the 

 cause s of the rupture of axles, and generally of pieces of iron, that 

 are subjected to repeated vibrations. 



BOOKS AND PAMPHLETS RECEIVED 



British.— The Native Faces of the P.ncific ?tates of North America: 

 Hubert Howe Bancroft ([.ongraans),—As:yrian Discoveries: George Smith 

 (Sampson Low and Mansion).— Valleys, .ind their Relation to Fissuies, 

 Fractures, and Faults: C. H. Kinahan, M.R.I. A., F.R.G.S.I., &c. 

 (Triibner).— Newcastle-upon-Tyne Chemical Society : On the Manufacture 

 of Caustic Soda.— Bird Life, by Dr. A. E. Brehm. Tr.anslated by H. M. 

 Labouchere, F Z.S., .and W. Jesse, C.M.Z.S. Parts 5 to 10 (John V.an 

 Voorst). — Logarithmic and Trigonometrical Tables for Approximate Calcu- 

 Lation: J. T Bottomley, MA., F.R.S.E. (\Vm. Collins).— Fr.agmentary 

 Papers by the late Sir H. Holland : Rev. J. Holland (Longmans).— Outline 

 of the Evolution- Philosophy, by Dr. M. E. Gazelles. Translated by the 

 Rev. O. B. Frothingham, of New York (Trubner).— The History of India 

 from the Eariiest Ages. Vol. iii. : J. Talboys Wheeler (Trubner) —The 

 Counte-s of Chinchon and the Chinchona Genus: Clements R. Markham, 

 C.B., F.RS. (Trubner). 



CONTENTS Pagk 



Botanical Problems . . . ; 261 



South American Tkavel, II. (lyith lUustratiotis) 262 



Watson's " Descriptive Geometry " 265 



Phillips' '* Elements OF Metallurgy" 266 



Our Book Shelf:— 



Schmidt's " Doctrine of Descent and Darwinism " 267 



Griffith and Henfrey's " Micrographic Dictionary " 267 



*' Temperature Chart of tile United States" 267 



Letters to the Editor : — 



Sub-Wealden Exploration— J. F. Blake 267 



The Rhinoceros in New Guinea —Dr. A. B. Meyer ; Albert O. 



Walker 168 



Geology and the Arctic Expedition. — Samuel Allport .... 268 



Upper Currents over Areas of Frost.— W. Clement Ley, . . . 2eQ 

 Decomposition of Iron Pyrites.— W. Mattieu Williams. F.CS. ; 



Geo. Lingwood : A. P. Wire 269 



Our Astronomical Column : — 



Variable Stars 2C9 



The Zodiacal Light 270 



Encke's Comet 270 



Halley's Comet 270 



Annual Report of the Warden of the Standards 270 



Schreiber's European Herpetology 271 



Botany IN Queensland. By John R.Jackson 271 



The Tock-Tay, or Large House Lizard of Eastern Bengal . . 27a 



Notes 272 



Determination of the Velocity of Light and of the Sun's 



Parallax. ByM.A. Coenu. 274 



<^N the Mlsculak Mechanical Work done before Exhaustion, 



II. By Frank E. NiPHER (W'/M ///Ki/7-aWoM) 276 



Scientific Serials ; . . . 277 



Societies and Academies 278 



Books and Pamphlets Received 2S0 



