36 



NATURE 



\May 14, 1S74 



ing ; a portion cut out from the side of this plate served for the 

 new trial plate. Its composition ranges from 924'6 to 925'! 

 parts of pure silver per 1,000 (925 being the standard). The 

 author has also constructed supplementary plates of pure silver 

 and gold. An interesting table of assays of trial plates from 

 1477 down to the present time is given. — Mr. J. Hannay con- 

 tributes a description of a sp. gr. apparatus for temperatures other 

 than atmospheric. — Dr. GLidstone and Mr. Tribe give the fourth 

 part of their researches on the action of the copper-zinc couple 

 on organic substances. They have rtow turned their attention to 

 the series containing the C„Il2|,_ J radicals, the first body acted 

 upon being iodide of ally], which yields with the dry couple a 

 resinous body of the formula n(C3H4), tut when mixed with 

 ether rapid decomposition sets in at ordinary temperatures, and 

 the ethereal solution gives zinc oxide on mixing with water. All 

 attempts to isolate zinc-allyl have, however, failed. Allyl iodide 

 and water acted upon by the couple give propylene CjHrJ-f 

 H.jO + Zn = ZnI.HO + C3H|,. The iodide mi.xed with alco- 

 hol is acted upon violently by zinc alone yielding propylene 



CsHjI + aHeO-l-Zn^Zn | j-^'^'-' + CjHj.— On fenous anhy- 

 dro-sulphate, by T. Bolas. A mixture of 10 per cent, of a 

 saturated aqueous solution of ferrous-sulpliate witli oil of vitriol 

 deposits, on cooling, small white prismatic crystals having the 

 formula FeS20j. When exposed to moist air the anhydro- 

 sulphate yields granular crystals of the formula FeS04.6H20. — 

 On tetranickelous phosphide, by Dr. R. Schenk. This substance 

 (NijP;) was obtained by adding a sufficient quantity of tartaric 

 acid to a solution of nickelous chloride, to prevent precipitation 

 by potash, boiling the potash solution with phosphorus and 

 then drying the precipitate in a stream of hydrogen. The re- 

 mainder of the journal is devoted to the usual abstracts from 

 other journals, British and foreign. 



Poggcndorff's Annakndcr Physik timi C/tanic, No. 2, 1S74. — 

 In the commencing paper, by M. Hermann Herwig, it appears 

 demonstrated that the conducting power of mercury, for heat, 

 is perfectly constant between 40" and 160°. — A continuation of 

 Julius Thomsen's Thermo-chemicil Researches treats of several 

 agents of oxidation and reduction ; and in the next paper. Dr. 

 Kontgen discusses several points connected with M. Kundt's 

 dust-figures (produced when a metallic plate, strewn with lyco- 

 podium, receives an electric spark) : the dependence of the size 

 of the dust-circle on the nature of the gas in which tlie discharge 

 occurs ; on the thickness of the lycopodium layer ; on the dis- 

 tance of wire-point from plate ; and on the kind of electricity 

 that is in the plate. He also studies the mode of production of 

 the figure, the natuie of the discharge, and the phenomena to 

 which Prof Guthrie lately called attention. — The concluding 

 portion of M. Br&un's paper on elastic vibrations whose ampli- 

 tudes are not infnilely small, is given. Various experiments 

 were made with ste;l rods, and it is shown that the pitch of tone 

 decreases if the amplitude increases, and that v/ith high tones 

 the influence of amplitude is greater than with low. The dead- 

 ening is dependent on pilch of tone (being greater for higher 

 tones), on amplitude (the influence of which is .also greater the 

 higher the tone), and en figure of vibrations (those in one direc- 

 tion being more deadened when there are simultaneous vibrations 

 in the direction at right angles). — This article is followed by a 

 translation of Prof Roscoe's account of a self-registering instru- 

 ment for meteorological measurements of light. — A paper by M, 

 Friedrich C. G. Midler (first part) has for its subject galvanic 

 polarisation, and the distribution of the current in electrolytes. 

 The author's experimental plan was (i) to vary the section and 

 length of a parallelipipedal electrolyte, and the size of the pole 

 plates, and determine each time the resistance ; (2) to insert 

 metallic conductors of small res:stance (e.g. thick copper-wire) 

 in the long direction of the liquiel conductor, but not touching 

 the electrodes, and measure the increase of conduction; (3) to 

 measure the cun^ent-density in different portions of any section 

 by the electrolytic action taking place on a small plate brought to 

 that part. — M. Avenarius has a p.aper On internal latent heat, 

 in which he arrives at the conclusion that the temperatures (deter- 

 mined by direct observations) of the volatilisation of a liquid 

 in a hermetically-closed space, perfectly agree with those calcu- 

 lated on the basis of empiric formukx: for internal latent heat. 

 The experiments were made with ether, sulphide of carbon, 

 chloride of c;;rbon, and aceton. — Prof Julius Kohn proposes a 

 simplification of Keinig's method of manomelric flames, doing 

 away with the membrane, and making the sound pass from the 

 mouth of an organ-pipe, i-.f. through a narrow glass tube, 



directly to the base of the flame (whose motions are mirrored in 

 the revolving case, as usual) — In an article On the motion and 

 action of glaciers. Dr. Pfaff describes some very delicate mea- 

 surements he lately made on the Aletsch glacier, which seemed 

 to prove that the progressive motion of the ice took place with- 

 out any break. A minimum motion of 8 mm. per hour was 

 observed at noon, and a maximum of 30mm. about 5 P.M. ; the 

 latter being thus nearly four times the former. Dr. Pfaff also 

 urges a number of considerations against certain theories of val- 

 ley-formation by glaciers. — The only remaining paper is one On 

 function of magnetisation of various iron bodies, by Prof Stole- 

 tow, of Moscow. 



Vn- Katurjorscher, March. — In this number are described a 

 series of experiments by M. Ilansemann, who considers they 

 demonstrate the production of a difference of temperature, in 

 columns of air, by the attraction of the earth. — An account is 

 given of recent observations by Dr. Boitzmann, on what he calls 

 " dielectric action at a distance." If the hypothesis be correct 

 (he argued), that in the molecules of an insulator, by electric 

 forces, positive electricity is driven to one side and negative to 

 the other, then an originally uneleclrified, insulating body 

 brought near one which is charged with electricity, must be 

 attracted by it, simply through clielectric polarisation of the 

 molecules, and without conduction ; in fact, as a piece of soft 

 iron is attracted to a magnet. Experiment confirmed this ; and he 

 determined, by his new method, the "dielectric constants" of 

 several insulating substances. — We might here also call attention 

 to M. Barthelemy's striking experiments in ^^bration forms, 

 produced at the surface of liquids by means of vibrating tuning- 

 forks. In square vessels containing mercuiy, systems of bright 

 lines appear parallel to the sides, and the breadth of the waves is 

 in inverse proportion to the number of vibrations. In this way 

 is explained Prof Tyndall's observation that many liquids are 

 not set in wave-motion by vibrations. Such is the case when 

 the breadth of the waves is greater than the breadth of the 

 vessel ; there can only then be a motion of the whole surface. 

 The distance between two lines corresponding to the same pitch 

 of fork is found to be independent of the density of the liquid. 

 M. Barthelemy experimented also with round, three-cornered, 

 and elliptical vessels, and on the rhythmical vertical flow of 

 water from narrow orifices. — M. Sporer adduces evidence of the 

 presence of ascending and descending currents in the atmosphere 

 of the sun. — Vhere are also, in the physical department, notes 

 of IlelmhoUz's researches on galvanic polarisation in gasless 

 liquids, Lockyer's on spectrum analysis of metals, Tyndall's on 

 conduction of .sound through the atmosphere, iS:c. — In geok>gy, 

 we find a summary of M. Laube's late observations as to the 

 evidence of a much more intense Ice-period in Greenland than the 

 present ; while M. P'uchs describes the geological formation of 

 the region about Nizza, south of the Maritime Alps. — Two 

 curiom cases of mimicry in the Articulata are discussed in a 

 note by M. Gerstaecken, who theorises on the nature of the 

 general phenomenon ; and there is, in the same section, a paper by 

 M. Milne-Edwards, in wiiich the colour of biros is studied in 

 relation to their geographical distribution. — In botany, lastly, 

 the fillowing topics are treated ; immigration of a rust fungus, 

 PiiCiinca mitk'aciantm (from Chili) ; light and the regeneration 

 of albuminous matter from .-isparagine ; and the electrical pheno- 

 mena in the leaves of Dionrej. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, April 30. — On Leaf arrangement, by 

 Hubert Airy, M.A., M.D. Communicated by Charles Darwin, 

 F.R.S. Received March 23, 1S74. 



The author is led to suppose : - 



I. That the original form of leaf-arrangement was two- 

 ranked. 



II. That this original two-ranked form gave rise to forms 

 with 2, 3, 4, 5, 6, 7, &c,, ranks, by "sporting," as opposed to 

 any process of accumulative modification. 



III. That, of the orders so formed, those with an even 

 number of r.inks (except 2) have, as a rule, assumed a wJicihd 

 arrangement, and those with two or an odd number of ranks 

 have assumed an nttci-nate arrangement, under the need of lateral 

 accommodation of ranks in the bud (taken as type of close- 

 packed forms). 



