Nov. 2 2, 1883] 



NA TURE 



95 



ending into a capillary. The wide end was sealed, and a dilato- 

 metric fluid such as oil introduced. The conclusions arrived at 

 are that tin, soft solder, and probably also lead, expand on melt- 

 ing ; but bismuth contracts. Many observations were made on 

 alloys of bismuth and lead. — On the liquefaction of oxygen, 

 nitrogen, and carbonic oxide, by S. von Wrublew-ld and C. 

 Olszewski. Intense cold was obtained by evaporation, under 

 reduced pressure, of liquefied ethylene in an apparatus modified 

 from that of Cailletet. Temperatures were measured by a 

 hydrogen pressure-thermometer. Oxygen proved to be liquefi- 

 able at temperatures varying from - I29°'6 to - I35°'8 C, 

 under pressures varying from 27 '02 to 22 '2 atmospheres. The 

 liquefaction of nitrogen and of carbonic oxide proved more diffi- 

 cult, and was not accomplished at a temperature of - 136" C, 

 even under a pressure of 150 atmospheres, though a sudden re- 

 lease of pressure produced a temporary mist of condensed 

 spherules, and a slower release of pressure yielded a deposit of 

 liquid with a distinct meniscus. Liquefied nitrogen and liquefied 

 carbonic oxide are both colourless and transparent. — C3n the 

 internal friction of certain solutions, and on the viscosity of 

 water at different temperatures, by K. F. Slotte. The results 

 confirm those previously obtained by Rosencrantz and Poiseulle. 

 — On a lecture app.iratus for demonstrating Poiseulle's law, by 

 W. C. Rontgen. — On the deduction of the crystal systems from 

 the theory of elasticity, by H. Aron ; a mathematical discussion 

 of the possible cases arising from the position of planes of sym- 

 metry', proving that no others than the recognised six systems of 

 crystals can exist. — On the properties of benzine as an insulator 

 and as a substance exhibiting electric reaction, by H. Hertz. 

 Pi/ri benzine appears to be remarkably good as an insulator and 

 remarkalily free from reaction effects. — On the influence of gal- 

 vanic polarisation on friction, by K. Waitz. Treats of the 

 phenomenon discovered by Edison, and recently examined by 

 K. R. Koch. — On the properties of calc-spar in the homogeneous 

 magnetic field, by Fr. Stenger. — Notes on a phoiometric appa- 

 ratus, by Leonhard Weber. — On "the Exhibition of the 

 Treatise on Light " of Ibn al Haitam, by E. Wiedemann. — On 

 the Cologne air-pump of the year 1641, a historical notice by 

 Dr. G. Berthold. — Remarks on the memoir of Herr Christian- 

 sen, *' Researches on Heat-Conductivity," by A. Winkelmann. 

 A/i! of the Royal Academy dei Lined, July 12-15, 1883. — 

 Obituary notice of William Spottiswoode, — Two communica- 

 tions from Signor Tacchini on the observations made by him at 

 Caroline Island during the solar eclipse of May 6, 1S83. — On 

 the average variation in tension of the atmospheric aqueous 

 vapour according to latitude and elevation in Italy, by A. Lugli. 

 — Meteorological observations at the Royal Observatory of the 

 Campidoglio for the months of June and July. — Most of the 

 present number is occupied with the new reforms and statutes of 

 the Academy, w hose constitution has recently been remodelled. 

 There are also long inventories of the works of art, furniture, 

 and fixtures of the Palazzo Corsini, which has been purchased as 

 the future home of the Academy. 



Rivisia Seientifico htdustriale, Flo7ence, September I5"30. — 

 The total eclipse of May 6. Results of the observations of 

 Tacchini, Janssen, and others, in Caroline Island. — Eclipses and 

 terrestrial magnetism, by P. Denza. All coimection is denied 

 between eclipses and magnetic phenomena. — On the compressi- 

 bility of water, by ,S. Pagliani and G. Vicentini. — A new electro- 

 dynamometer, by Prof. Bellati. — On the deformation detected 

 by Gouy in polarised electrodes, by A. Volta. — An im|. roved 

 reversible magnetico-electric machine, by M. Delaurier. — Ana- 

 tomical description of two extremely rare buds (Somateria 

 nwlUssima and Phalayoptis ftdiearius) preserved in the Civic 

 Museum of Venice, by P. A. Ninni. — On the fossil vertebrates 

 of the Miocene formations in the Venetian Alps, by Baron 

 Achille de Zigno.- — On the fossil ga.stropods, cephalopods, and 

 corals of the lower titonic formations of Sicily, by Dr. G. de 

 Stefano. 



SOCIETIES AND ACADEMIES 

 London 

 Chemical Society, Novemlier 15. — Dr. Perkin, F.R.S., pre- 

 sident, in the chair.^It was announced that a ballot would take 

 place at the next meeting (Dec. 6). — The following; papers were 

 read : — On the estimation of starch, by C. O'SulIivan. The 

 method may be briefly described as follows :— About five grms. 

 of the finely ground grain are successively extracted with ether, 



alcohol (sp. gr. o'9o), and water at 35° to 38°. Fat, sugar, 

 albuminoids, amylams, &c., are thus got rid of. The starch in 

 the washed residue is gelatinised by boiling with water, cooled 

 to 62°, about 003 grm. diatase (prepared by precipitating a 

 cold, aqueo-s extract of malt with alcohol) added ; the starch 

 is thus converted entirely into maltose and dextrin, and by a 

 quantitative determination of these two products the starch 

 originally present can be calculated. The author states, as the 

 result of his experience with the method, that the difference in 

 results obtained by any two observers need not exceed o'5 per 

 cent, of the total starch — On the illuminating power of ethylene 

 when burnt with non-luminous combustible gases, by P. F. 

 Frankland. The author summarises his results as follows : — 

 Pure ethylene burnt at the rate of five cubic feet per hour from 

 a Referees Arsjand burner, emits a light of 68'5 standard 

 candles ; the illuminating power of equal volumes of mixtures 

 of ethylene with either hydrogen, carbon monoxide, or marsh 

 gas is less than that of pure ethylene ; when such mixtures con- 

 tain 60 per cent, of ethylene or more, the illuminating power of 

 the mixture is but slightly affected by the nature of the dilu- 

 ent ; in mixtures containing less than 60 per cent, of ethylene, 

 the illuminating power is the highest when marsh gas, and lowest 

 when carbon monoxide, is the diluent. — On the products of de- 

 composition of aqueous solutions of ammonium nitrite, by G. 

 S. Johnson. The nitrogen evolved from alkaline solutions of 

 ammonium nitrite contains no oxides of nitrogen; nitrogen is 

 evolved from aqueous solutions below ioo°; by adding crystallised 

 cupric chloride, a continuous evolution of pure nitrogen takes place 

 in the cold. When solutions are acid, the nitrogen may contain 

 4 per cent, of nitric oxide. About 2 per cent, of the nitrogen 

 evolved by the cupric chloride is stated by the author to possess 

 peculiarly active properties, and forms ammonia when passed 

 with hydrogen over spongy platinum. — On the estimation of 

 iron by standard potassium bichromate, by E. B. Schmidt. The 

 author recommends the above process, but states that zinc should 

 not be used to reduce the iron, as it interferes with the end 

 reaction with potas-ium ferricyanide. He prefers Kessler's 

 method of reduction with stannous chloride. 



Western Microscopical Club, November 5. — Mr. W. 

 Crookes gave a lecture on " Recent Discoveries in High 

 Vacua." He illustrated his theme with a series of brilliant 

 and interesting experiments. The effects \vere produced by 

 a large electric coil, having sixty miles of secondary wire, 

 and worked by two cells of a storage-battery. The coil, 

 when attached to its full complement of thirty cells, would 

 give a spark in air of twenty-four inches. "High vacua" 

 were defined as those ranging from above the l/iooo to the 

 1/100,000,000 of an atmosphere. Air and all gases are con- 

 ceived to consist of myriads of excessively minute molecules, 

 which in the ordinary state vibrate with enormous velocity ; but 

 being crowded together in that condition their extent of vibration 

 is impeded liy each other, and is, in fact, limited to a path of 

 only 1/10,000 of a millimetre. When, as in a partial vacuum, 

 there are fewer of these molecules, they have more room in which 

 to vibrate, and hence their " mean length of path " is increased. 

 Under the influence of eleclricity these molecules are driven 

 in straight lines fi-om the negative pole. In a comparatively low 

 vacuum, on the passage of an electric current, the residual air 

 assumes a stratified condition, showing alternate light and dark 

 bands. The width of the dark bands marks the length of the 

 excursions of the molecules. Further exhaustion increases the 

 width of these bands, so that in a vacuum of 1/1,000,000 of an 

 atmosphere ihe free path of the molecules was seen to extend 

 to about four inches. By means of an exhausted V-shaped 

 tube it was shonn that these molecules are driven from the 

 negative pole in straight lines, and hence cannot turn a corner. 

 First one limb of the V, then the other, was connected with 

 the negative pole of the coil, with the result that each in turn 

 was in darkness. In another vacuum-tube a concave nega- 

 tive pole w as fixed ; the molecules were driven normally 

 from this concave surface, and, meeting the cylindrical surface 

 of the glass inclosure, were thrown into beautiful caustic curves. 

 That these molecules, under the influence of electricity, pos- 

 sessed mechanical force was shown by causing them to impinge 

 on the vanes of a radiometer, when a rapid rotation took place. 

 On reversing the current, the direction of rotation was also re- 

 versed. That this was not due merely to the passage of an 

 electric current was shown by a vacuum-tube containing a small, 

 horizontal "water-wheel." Its upper and lower floats being 

 struck equally by the radiant matter, no motion took place ; but 



