5 68 



NA TURE 



[Oct. 5, 1882 



must be heated about 240° above its boiling-point before its 

 density becomes strictly normal. From the experiments of V. 

 Meyer and others, iodine vapour appears to be normal a very 

 few degrees above the boiling-point. It appears, therefore, 

 probable that vapour of chlorine, bromine, or iodine at low tem- 

 peratures, contains groups of molecules which are dissociated as 

 the temperature rises, and that the greater the molecular weight 

 the more easily are these molecular groups dissociated. 



Reference was made in a note (Nature, vol. xxvi. p. 306), 

 to Spring's researches on the expansion of isomorphous com- 

 pounds ; in last number of the Berliner Berichte Pettersson 

 draws attention to accurate determinations of the specific gravi- 

 ties of various alums, published by him a few years ago, which 

 ;. roved that the quotients of the specific gravities of the alums 

 by their respective formula weigh' s, are not equal, as assumed 

 by Spring, but show considerable differences. Spring's work 

 on the expansion of alums may lead to interesting results, but it 

 seems evident that he has been too hasty in drawing sweeping 

 conclusions regarding the molecular structure of solids from 

 quite insufficient data. 



Herr G. Xruss describes [Berliner Berichte, xv. 1243] a 

 spectroscopic method for determining whether there is, or is not, 

 any chemical action occurring in a solution containing two or 

 more coloured salts. The method consists essentially in com- 

 paring the sums of the absorption spectra of the individual salts 

 with the absorption spectrum of the solution containing all the 

 salts. 



An abstract of an important paper by Mendelejeff on thermo- 

 chemistry appeared in the Berichte for July 10 [xx. 1555]. Men- 

 delejeff asserts that the data hitherto attained by Berthelot, 

 Thomsen, and others regarding the "heats of formation" 

 of hydrocarbons stand in need of correction, because allowance 

 has not been made for the physical changes, involving absorp- 

 tion or evolution of heat, which in every case accompany the 

 chemical changes considered. Mendelejeff gives a table showing 

 the "heats of formation" from marsh gas, carbon monoxide, 

 and carbon dioxide, of a series of hydrocarbons ; the chemical 

 reactions, the thermal equivalents of which are set down in this 

 fable, are reactions which actually occur, unlike the reactions of 

 formation of Berthelot and others, which as a rule cannot be 

 realised in actual experiments. 



Messrs. Smith and Lowe find that when chlorine is passed 

 through a porcelain tube heated to 1030°, and then into potas- 

 sium iodide solution, less iodine is liberated than is the case when 

 the same quantity of chlorine is allowed to act on the iodide at 

 ordinary temperature ; they conclude, therefore, that chlorine is 

 partly dissociated at a temperature of 1030° (Chem. Nrdis, xlv. 

 226). 



According to Mixter (Amir. Chem. J., iv. 35), urea is 

 readily obtained by passing ammonia and carbon dioxide through 

 a red-hot tube : ammonium cyanate is probably produced, and 

 then transformed into urea. 



Selmi (R. Acad, del Lincei, v. 174) states that he has 

 found alkaluid.il compounds having specific poisonous actions in 

 the urine of patients suffering from paralysis, tetanus, &c. Me 

 considers death to be determined by the action of these poisons 

 produced by the progress of the disease. 



By electrolysing water by a powerful current, using a positive 

 electrode of gas-coke purified by the action of chlorine at a very 

 high temperature, Bartoli and Papasogli (Gazzetta Chim. Hal., 

 1882, 113) obtained a black solution, which, when acidified with 

 hydrochloric acid, yielded a black substance having the compo- 

 sition C u H„0 4 (when dried at 140°). The properties of this 

 substance — Mellogen — are very peculiar ; in some points it 

 resembles graphitic acid ; it dissolves in water to form an inky- 

 black neutral liquid : on exposure to air or by the action of 

 oxidising agents it yields mellitic acid and other acids, which are 

 generally regarded as addition products of benzene. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 

 Prof. Bonney begins his course of lectures on Petrology, 

 Physiography, and Stratigraphical Geology at University Col- 

 lege, Gower Street, on October 10, at twelve o'clock. The 

 course will extend over two terms. Classes will also be formed 

 for catechetical instruction and for the study of the microscopic 

 structure of rocks. 



SOCIETIES AND ACADEMIES 

 Paris 

 Academy of Sciences, September 25.— M. Blanchard in the 

 chair. — A report was given of the ceremony at the recent in- 

 auguration of a statue to Antoine-Cesar Becquerel at Chatillon- 

 sur-Loing, on September 24, when addresses were delivered by 

 MM. Cochery, Dumas, Fremy, Mercadier, Barral, and the 

 Mayor. — On a question of principle which relates to the theory 

 of shock of imperfectly elastic bodies, by M. Resal. — Outbreaks of 

 plague in Kurdistan during the last twelve years, by M. 

 Thalozan. The facts are thought to afford further proof of the 

 independence of most of the plague-centres, the small tendency 

 of the disease to spread beyond a small number of localities, 

 and the limited duration of the epidemics, even in their gravest 

 form. The north and north-west of Persia are the parts where 

 plague-epidemics are less rare. — Possibility of introducing a tube 

 into the larynx without producing pain or any reaction, by M. 

 Brown-Sequard. He produces local anaesthesia in mammalia 

 by directing a rapid current of carbonic acid on the upper part of 

 the larynx (through an incision), for a variable time (fifteen 

 seconds to two or three minutes). The effect lasts two to eight 

 minutes after stoppage. — A telegram from the Emperor of Brazil 

 (dated Rio, September 12, 6h. 10m.), announced the observation 

 (at Rio Observatory) of a brilliant comet ; estimated position in the 

 morning, ascension ioh., declination 2°S. "probably Pcna's comet 

 expected. — On a comet observed at Nice, by MM. Thollon and 

 Gouy. This was visible near the sun on September 18, at mid- 

 day, to the naked eye, when the direct solar rays were masked. 

 The spectrum had for essential character the presence of the 

 bright lines of sodium (fine and perfectly separate) in the nucleus 

 and parts near. A slight displacement was held to indicate 

 withdrawal from the earth. No part of the comet showed bands 

 of carbon, nor any band or line but those of sodium (probably 

 because of a masking by diffuse light). On the morning of the 

 21st the comet had become invisible. — M. Flammarion com- 

 municated telegrams from Spain, Portugal, the South of France, 

 Algeria, and Italy, announcing observations of a comet on Sep- 

 tember 17, 18, and 19. — On an observation of the great comet 

 of 1882, seen from a balloon, by M. de Fonvielle. M. Mallet 

 made the ascent at his request (having keener vision), and took 

 some measurements. The diameter of the comet was about two- 

 tenths of that of the sun, and the distance of the comet's centre 

 from that of the sun about 2 "3 subjective dhmeters of the sun. 

 The cometary sphere was penetrated by an isosceles cone, sym- 

 metrically placed to the line of centres, penetrating to two-thirds 

 of its vertical meridian plane. The length of the apothem of 

 the cone was about a solar radius. — Description of a complete 

 regular dodecahedron, by M. Barbier. — On the development of 

 Alcyonarians, by MM. Kowalewsky and Marion. — On the his- 

 tological structure of the digestive tube of Holotkuria tubulosa, 

 by M. Sourdan. — Analysis of the milk of Galibi women at the 

 Jardin d'Acclimatation, by Mdme. Bres. The milk is rich in 

 butter and lactose, and there is very little casein. 



CONTENTS Pag. 



Fluids S4S 



Handbook of Invertebrate Zoology. By Prof. E. Ray Lan- 



kestpr, F.R.S 548 



Our Hook Shele: — 



White's " Cameos from the Silver-land " 54? 



Letteks to the Editor: — 



The Recent Aurora.— Prof. J. P. O'Reilly : Sydney Evershed : 



VV. T. Lineham; Dr. Oustave PlaRR ; Elizth Brown . . 5« 8 



An Insect attacking a Worm.— Edwin Lawrence 549 



White Ants.— Surgeon-Major C. Eidie 549 



British Sponges 55° 



Exploration in Siam 55° 



The Comet . 55' 



Spectroscopic Weather Discussions. By Prof. C. Piazzi Smyth, 



Astronomer Royal for Scotland (With Diagrams) 55' 



Electric Navigation. By Prof. Silvanus P. Thompson (With 



Illustrations') 554 



Notes 55° 



Biological Notes: — 



On a New Genus of CryP''" , phycea: . . . - • 557 



Seed Leaves of Bursera (With Illustration) 55° 



Affinities of the Bower Birds 55| 



Geographical Notes 55° 



Pelagic Lipe. By Prof. H. N. Moseley. F.R.S 559 



Underground Temperature 5°4 



Mitamorphic Rocks op Bergen 5W 



Chemical Notes ' \ 



Umversity and Educational Intelligence SjM 



Societies and Academies 5° 8 



