196 



NA TURE 



[April 23, \\ 



germs in the atmosphere, by M. J. Hericourt. The author 

 finds that these organisms are normally present in all kinds of 

 water, and in the form of spores or germs everywhere in the 

 atmosphere. There are many varieties, some apparently identical 

 with the comma bacillus of cholera. 



Berlin 



Physical Society, March 6.— Dr. Kalischer described anew 

 secondary battery intended to overcome the disadvantage of the 

 usual accumulators, namely, that the sheet of lead used as anode 

 got very soon destroyed. This object he attained by adopting 

 a very concentrated solution of nitrate of lead as electrolyte, and 

 iron as anode. The iron, on being immersed in the solution of 

 lead, became passive and resisted every corroding effect of the 

 fluid ; in other respects the peroxide of lead on the electric charge 

 became deposited at the anode as a very firm coherent mass 

 enveloping and protecting the iron on all sides. The charge 

 was continued till the greater part of the nitrate of lead was 

 decomposed, a condition which was marked by the occurrence 

 of a greater development of gas at the anode. At the beginning 

 of the charge all development of gas must be avoided, as other- 

 wise the peroxide of lead, or, more correctly, the hydrate of per- 

 oxide of lead, became covered with bubbles. As kathode a sheet 

 of lead was used, but it was attended by two disadvantages. In 

 the first place the lead, during the charge, separated itself at 

 the kathode into long crystal threads, which soon passed through 

 the fluid and produced short closing (of the current). In the 

 second place the nitric acid, which remained in the fluid after 

 the separation of the lead, acted very powerfully on the sheet of 

 lead. Both disadvantages Dr. Kalischer avoided by amalgam- 

 ising the kathode. This accumulator of iron, concentrated 

 solution of nitrate of lead, and amalgamised lead yielded, after 

 the electric charge, which could be carried out without any 

 special preparations, a current of about 2 volts ; after about six 

 hours' discharge, however, the electromotive force sank to 17 

 volts, but, on the battery being left to itself for twenty-four hours, 

 it became a little increased. According to the measurements 

 hitherto taken, the functions of this accumulator were satisfactory. 

 An attempt to substitute sulphuric manganese for nitric lead in 

 this battery did not answer the purpose, as the peroxide of 

 manganese separated itself, not in a continuous layer, but in 

 loose scales. — Prof. Schwalbe laid before the Society a piece of 

 a piezometer which had burst under a pressure of ten atmo- 

 spheres. The rather thick glass was traversed by longitudinal 

 fissures, distributed with perfect regularity and exactly parallel 

 to each other. — Prof. Schwalbe further spoke of the ice- 

 outcroppings, resembling asbestos and glossy-like silk, which 

 emerged on old, decayed twigs and branches, and which he had 

 observed in former winters. He supposed that they origin- 

 ated in the crystallisation outwards of needles of ice from the 

 water in the interior of the wood under moderate and slowly 

 advancing colds. This winter also, as in former winters, he had 

 succeeded in effecting these glacial outgrowths artificially on 

 some twigs, by impregnating them with water and then exposing 

 them to a slow increasing cold of from - 2° to - 3°. To test the 

 accuracy of this hypothesis, he instituted experiments with 

 solutions of salt. A solution of nitre gave very satisfactory 

 results. When a'decayed twig was thoroughly saturated with a 

 solution of nitre, and then left to evaporate, there then cropped 

 out on it delicate glossy protuberances, perfectly similar to those 

 observed in nature on moist pieces of wood. In this last case 

 it was impossible that any increment could come from the out- 

 side ; these crystal needles could have grown only from the 

 interior. With the cube-crystallising kitchen salt, on the other 

 hand, the experiment did not succeed. The speaker related 

 that the first observations of these ice outcroppages were made 

 by the Duke of Argyll. The pillar-like outgrowths which in 

 recent times had been largely observed by English naturalists, 

 and which he had formerly observed and described, were, in the 

 opinion of the speaker, likewise excrescences from the interior. 

 — Dr. Kayser read a paper, sent in by Dr. Miiller-Erzbach, in 

 which the latter endeavoured to refute some objections raised 

 ajainst his experiments, communicated to the Society at the last 

 sitting, respecting the magnitude of the sphere of influence of 

 molecular attraction. 



March 20. — Dr. Gross, starting from theoretical con- 

 siderations, instituted the following experiment : — Two iron 

 electrodes overlaid with sealing wax, in such a manner a 

 1 1 leave only the terminal planes free, were dipped into 



solution of chloride of iron, closed by means of a galvanometer 

 into a circle, and any inequalities there might happen to be 

 adjusted according to the Poggendorf-Du Bois-Raymond 

 method. When now one electrode was surrounded by a 

 magnetising spiral, there was seen, on its being magnetised, an 

 electric current passing from the magnetic electrode through 

 the fluid to the non-magnetic electrode. It might be thought 

 that the current was a thermo-electric one, produced by the 

 warming of the magnetising spiral ; but a delicate thermometer 

 showed that the air within the magnetising spiral was but 2 

 warmer than the surrounding air. Besides, the electrode that 

 was to be magnetised was surrounded by a double cylinder, 

 through which water of a temperature 12° below that of the air, 

 was constantly flowing ; and yet, notwithstanding this power- 

 fully cooling influence, the current always passed from the mag- 

 netic to the non-magnetic electrode, whereas a thermal current 

 must have passed from the warm to the cold electrode. The 

 electric current was therefore produced, not by a difference in 

 temperature, but by the magnetisation of the one electrode. The 

 current continued so long as the electrode was magnetised. If 

 the electrodes were now brought into a tube, and so arranged as 

 to lie behind each other in the axis of the tube, with their free 

 terminal planes turned to each other, then, on the magnetisation 

 of one electrode, an electric current again set in, passing now, 

 however, from the non-magnetic electrode, through the fluid, to 

 the magnetic electrode. The direction of the current was con- 

 sequently dependent on the direction of the magnetic axis to the 

 electrolyte and the second electrode. As conducting fluid only 

 sulphates of iron could be used in these experiments, and of 

 these only such as received the free terminal plane of the elec- 

 trodes nakedly. Dr. Gross believed that the currents demon- 

 strated by him in the experiments thus described were related to 

 the thermo-electric currents between magnetic and non-mag- 

 netic iron wires, which were a subject of study to Sir William 

 Thomson. 



CONTENTS Page 



The "Challenger" Expedition 573 



Frankland and Japp's Inorganic Chemistry. By 



Prof. M. M. P. Muir 576 



Letters to the Editor : — 



Mr. Lowne on the Morphology of Insects' Eyes. — 



Prof. E. Ray Lankester, F.R.S 578 



Abnormal Season in the Niger Delta. — Prof. J. P. 



O'Reilly 578 



Tardy Justice.— Z 578 



A Query.— M. X 578 



The Use of Artificial Teeth by the Ancients. — O. S. 578 



Far-sightedness. — J. Starkie Gardner 578 



Aims and Methods of the Teaching of Physics. 



By W. Odell 578 



The Work of the U.S. Signal Office under General 



Hazen 580 



A Recent Japanese Earthquake. By Prof. J. A. 



Ewing. {Illustrated) 581 



Early Maturity of Live Stock 5S2 



The Borneo Coal-Fields. By Rev. J. E. Tenison- 



Woods 583 



The Paris Central School of Arts and Manufactures. 



(Illustrated) 584 



Notes 5S6 



Our Astronomical Column : — 



Halley's Comet in 1456 588 



The Total Solar Eclipse on September 9 5S8 



Astronomical Phenomena for the Week 1885, 



April 26 to May 2 589 



Geographical Notes 589 



The Scottish Meteorological Society 590 



University and Educational Intelligence 591 



Scientific Serials 591 



Societies and Academies • 592 



