26o 



NATURE 



\^yuly lo, 1879 



steel compensating penchilum moved by its own gravity, but at 

 each beat made and broke a battery circuit by means of two bent 

 springs, one on either side. Tlie current passing through an 

 electro-magnet, detained a bent lever untii the pendulum swung 

 to the other contact. By this contrivance time was marked. 

 Prof. Macleod found that platinum contacts frequently stuck to- 

 gether in these experiments ; but this defect had been cured by 

 the use of a liquid shunt of dilute sulphuric acid, which destroyed 

 the extra current. This remedy had been suggested to him by 

 Lord Rayleigh. Prof. Macleod demonstrated the complete stic- 

 cess of this device, which acts as well as a condenser shunt. lie 

 had also observed a curious eflfect with these liquid shunts, which 

 as yet he could not explain. Two shunt-; having the same acid 

 in both were employed, one shunting the extra current from four 

 Daniell cells, and one that from two Daniell cells. The first 

 showed evolution of H and O gas, the platinum electrodes being 

 unaffected. The second showed no evolution of gas, but one 

 platinum plate was dissolved away and deposited in a black 

 powder on the other. He also exhibited a new cell formed of 

 zinc and mercury plates, with zincic-iodide solution and mer- 

 curous chloride salt. Red iodide of mercury is formed at the 

 negative electrode. The E M F is ■J-^X\i^ of a Daniell cell, but 

 the internal resistance very low and the cell very constant ; while 

 there is no local action. Prof. Guthrie suggested that the extra 

 current was really a succession of sparks ; the platinum might be 

 carried bodily over from one electrode to the other. Mr. F. H. 

 Varley stated that Mr. F. Higgins had observed a similar effect 

 with carbon electrodes in a voltameter, one carbon falling away 

 into a fine powder, and due perhaps to the disintegrating action 

 of liberated gases. He had also himself seen a platinum wire 

 in contact with a carbon one eaten thin and drawn into very fine 

 silky pens, while the carbon was stained blue, although the 

 current passing was of low ten>ion. Mr. Chandler Roberts sug- 

 gested that perhaps a hydride of platinum was formed in the 

 case mentioned by Prof. Macleod. Prof. Guthrie suggested ex- 

 p3riments with fluorescent liquid shunts in the dark. — Mr. J. 

 W. Clark then described some experiments on the surface ten- 

 sion of sulphurous anhydride, sealed in a capillary tube within a 

 second tube, containing the same substance. He found that at 

 low temperatures the level of the liquid is lower in the narrow 

 than in the wide tube. As the temperature rises the meniscus 

 in the narrow tube descends till about 156° Fahr. ; it is level with 

 that of the wider tube, both surfaces being slightly concave. 

 Above this temperature the surfaces become plane, then convex, 

 the level in the wide tube becoming higher than that in the narrow 

 one. These experiments are being continued, and Mr. Clark's 

 other results \\ill be comnunicated to the Society later on. — 

 Prof. Guthrie proposed a vote of thanks to Col. Chesney, 



Paris 



Academy of Sciences, June 30. — M. Daubree in the chair. 

 — The following papers were read : — On the chemical constitu- 

 tion of alkaline amalgams, by M. Berthelot. He shows that 

 the relative affinities of the two alkaline metals for oxygen 

 are inverted in their amalgams. This explains the singular 

 anomaly discovered by MM. Krant and Topp, viz., the displace- 

 ment of potassiimi in dissolved potash by amalgamated sodium, 

 producing the crystallised amalgam Hg24K. The displacement 

 is the necessary consequence of the greater loss of energy under- 

 gone by the potassium in the formation of the amalgam. — On a 

 peculiarity of an experiment of Gay Lussac and Thenard, by M, 

 Debray. The experiment is that in which hydrated potash or 

 soda in vapour are passed over an excess of well cleaned iron in 

 a highly heated gun-barrel. Hydrogen and vapour of potassium 

 or sodium are liberated, the oxygen being fixed in part of the 

 iron. Gay Lussac and Thenard noticed, without explaining, that 

 the fixation was cliiefly on the metal in the part exterior to the 

 furnace, and therefore less hot. This M. Debray attributes to 

 the presence of vapour of the metal and of hydrogen remaining 

 in the apparatus. From experiments by M. SainteClaire De- 

 ville, it may be deduced that if a mass of iron incompletely 

 oxidised, and having its different parts at variable temperatures, 

 be in a more or less dense atmosphere of hydrogen, the oxygen 

 will quit the hotter parts .where it was originally fixed, and go to 

 the cooler. M. DetDray illustrates the phenomena by an experi- 

 ment. — Spectral examination of ytterbine, by M. Lecoq de 

 Boisbaudran. He gives the approximate position and form of 

 the bands, grouped chiefly between the solar lines D and F, of 

 which the spectrum is composed. — M. Dausse was elected Cor- 

 respondent in Mechanics in room of the late General Didion. — 



On atmospheric waves, by M. Bouquet de la Grye. This relates 

 to the results of some 15,000 observations of barometric height, 

 and direction and velocity of the winds, at Brest. The numbers 

 given as showing the maximum influence of solar and lunar 

 action prove the greatness of this action and the impossibility of 

 making serious predictions of weather before the atmospheric 

 laws dependent thereon have been studied. — On the nature 

 of the soil of the Isthmus of Gabes and the Chotts, by 

 M. Roudaire. He gives a summary of his observations (some 

 of which have been formerly referred to). His collections contain 

 about 300 plant species and 120 animal, several new; he has 

 also some 500 geological specimens, results of twenty-two 

 borings, daily observations of atmospheric pressure, tempera- 

 ture, hygrometry, the wind, &c. — On Stokes's law; reply to 

 M. Becquerel, by JI. Lamansky. — On the dissociation of 

 sulphydrate of ammonium, by MM. Engel and Moitessier. They 

 prove that sulphuretted hydrogen and ammonia do not combine 

 in equal volumes at 50°, and that the supposed vapour of sulphy- 

 drate of ammonium is merely a mixture of two gases. — Action 

 of phtalic anhydride on naphtaline in presence of chloride of 

 aluminium, by MM. Ador and Crafts. — On the ashes and lava 

 of the recent eruption of Etna, by M. Cossa. The very fine 

 blackish-grey ash is formed of fragments of crystals of triclinic 

 felspar, augite, small grains of magnetite, and a large number 

 of variously coloured splinters of glass. The lava is formed in 

 great part of large crystals of triclinic felspar disseminated por- 

 phyrically in a microcrystalline magma, formed of small crystals 

 of the same felspar, augite, magnetite, and a little greyish 

 vitreous matter. The phenomena (in M. Cossa's opinion) tell 

 against the hypothesis of pre-existence in the solid state of the 

 crystalline elements in lava vomited by volcanoes. — New re- 

 searches on development of the embryonal sac in angiospermons 

 phanerogams, by M. Vesque. — On a new substance of the epi- 

 dermis, and on the process of keratinisation of the epidermic 

 coat, by M. Ranvier. The new substance, found in the form of 

 drops in cells of the epidermis, and rapidly colourable red 

 with carmine, he calls eleidine ; it plays an important rile in 

 keratinisation of the epidermis. — On the structure of broad 

 ligaments, by M. Guerin. — On the state of glandular cells of 

 the submaxillary after prolonged excitation of the chorda tym- 

 pani, by MM. Arloing and Renaut. He concludes that these 

 cells have a proper individuality, and are not embryonal forms 

 of muciparous cells. — Forage in shocks of sheaves, by M. Dn- 

 plessis. Green forage may be transformed into hay, in rainy 

 weather, by arranging in shocks, and this transformation 

 takes place more surely and economically than by the old 

 method in the same circumstances. — On the ancient roads of the 

 Sahara, by M. Berlioux. Some old inscriptions have been dis- 

 covered by the German expedition in the Libyan Desert, on the 

 route the author had indicated as probably a Roman road at one 

 time. 



CONTENTS PAen 



Clements' Organic Chemistry 237 



Euclid and his Modern Rivals 240 



Letters to the Editor: — 



The Papau or Pap.iye.— Capt. S. P. Oliver 241 



On the Origin of Certain Granitoid Rocks. — Henry Hicks . . . 242 

 Distribution of the Black Rat {Mus ratti^, Linn.) in Italy. — Dr. 



Henry H. GiGLlOLl 242 



Barbed Hooklets on Spines of a Brachiopod. — Prof. John Young . 243 

 The Serpent Mound of Lochnell, near Ob.an.— C. \V. M. (IVith 



Diagram) 24J 



The Origin of Hail.— Ignora.mus (IVith Diagram) 242 



Butterfly Swarms.— F. H. Haines; W. Rees Swain 243 



Intellect in Brutes.— Dr. A. DupRi; J. B. R.; J. S. WkITTEM . 243 



Snails r'. Glow-worms. — R. S. Newall, F.R.S 243 



Occurrence of Boar Fish.— John T. Carrington 244 



Habits of Ants.— W. Whit.man Bailey 244 



William Fothergill Cooke 244 



The Comparative Anatomy of Man, II. By Prof. Flonvbr, 



F.R.S 244 



On the Secular Effects of Tidal Friction. By G. H. Darwin 246 



More Notes from Kilburn 347 



Our Astronomical Column: — 



The New Comet (Swift, June 2o) 248 



Tempel's Comet, 1S67 II 248 



The Variable-Star Pia2zi XIII. 126 248 



Geographical Notes 348 



Molecular Physics in High Vacua, II. By Willia.-^ Crookhs, 



¥. 'R.S. (IVMilllustratims) 250 



Notes 254 



The Genesis and Migrations OF Plants • • •. 257 



University and Educational Intelligence "ii 



Societies and Acabemies -5S 



