<May 12, 1881] 



NATURE 



41 



sweeping ephemerides for the whole year were published from 

 Strassburg some time since, and will be found in the Viertel- 

 jahi-sschrtft der Astronomischcn Gesdhchaft, Jahrgang 12. 

 Those given above apply to greater distance from perihelion. 



The Transit of Vehus, 1882. — At the sitting of the Paris 

 Academy of Sciences, on the 2nd inst., the Minister of Foreign 

 Affairs transmitted a letter from the British Ambassador, on the 

 part of his Government, desiiing to be informed with which 

 French authorities the Koyal Society of London should com- 

 municate, with the view to an interchange of opinions relative to 

 the observation of the approaching transit of Venus. The letter 

 was referred to a commission already nominited. 



Comet 1880, V. (Pechule, December 16). — This comet 

 was followed by M. Bigourdan until March 31, efforts having 

 been made at the Observatory of Paris to obsen-e it as long as 

 possible on account of the resemblance of the orbit to that of the 

 great comet of 1S07. M. Bigourdan's last elements gave the 

 place with errors of only 2s. 'o in right ascension, and 20" in 

 declination : they will be f jund in Comptes rendus, vol. xcii. 

 p. 172. 



Comet 1881, a (Swift, May i). — We have received from 

 the Imperial Observatory of Strassburg the follo«'ing observa- 

 tion of the new comet, made by Dr. Hartwig with the "orbit- 

 sweeper " : — 



May 5, at I4h. 56m. 9s. '8 mean time at Strassburg. 

 Right Ascension oh. 19m. 17s. 76; Declination -1-32^ 19' 32"'3. 



CHEMICAL NOTES 

 In the American Cltankal Journal Prof. Mallet describes a 

 simple form of calorimeter whereby the specific heats of mode- 

 rately small quantities of solids or liquids may be measured with 

 a fair degree of accuracy. Mercury is employed, instead of 

 water, as the material whose temperature is raised, and com- 

 parison is made, not of the total amju its of heat given out by 

 different bodies on cooling, but of fractions of this heat rendered 

 as nearly as possible equal. 



In Comft. rend. Berthelot gives several thermal measurements 

 showing that in the substitution of halogens for hyd ogen in 

 hydrocarbons, the quantity of heat evolved varies according to 

 the series aad chemical function of the hydrocarbjns employed, 

 and is generally smaller the greater the number of halogen 

 atoms substituted. The heat of formation of chloral alcoholate 

 in various physical states is also considered by Berthelot : among 

 otlier results it is shown that chloral hydrate is decompoed by an 

 excess of absolute alcohol, but that the alcoholate is decomposed 

 by much water; in the foi'mer of thesa actions there is exhibited 

 the decomposition of a more volatile comixjund — chloral hydrate 

 — and formation of a less volatile — chloral alcoholate ; and at 

 the same time the expulsion of a less volatile substance — water — • 

 by a more volatile — alcohol. 



The proto-salts of chromium (or chromous salts) are uustabl; 

 and but little known : in Coinj>t, rend. M. Moissiu describes 

 tHo salts belonging to this series, viz., chromous cliloride, CrClj, 

 and chromous sulphate, CrS047H20. 



In the Berichte of the German Chemical Society Herr C. 

 Zi mrarermann states that potas-iam permanganate may be used 

 for determining iron in presence of considerable quantities of 

 hydrochloric acid, if a solutio.i of mangauous chloride, or 

 preferably manganous sulphate, be added previous to titration. 



According to the hypothesis of Vant' Hoff, propyl glycol 

 ought to be an optically active liquid, inasmuch as the mole- 

 cule of this compound contain; one asymmetric carbon atoji, i.e. 

 an atom directly united with four different radicles ;— propyl 



CH3— C— CH.,OH 

 ghcol being formulated as /\ ' . Le Bel 



II OH 

 has recently shown {Compt, rend.) that if ordinary propyl 

 glycol — from glyceric acid — ^be su'ijected to partial fermenta- 

 tion, the unfermented residue exhibits slight dextrorotatory 

 powers. Le Bel thinks that ordinary propyl glycol contains both 

 an optically active and ao optically inactive modification, and 

 that the latter being decomposed by the ferment, the presence of 

 the former is rendered evident. From opticiUy active propyl 

 glj-col Le Bel has prepared an active propylene oxi le boiliag at 

 35', which he states is the most volatile optically active compound 

 at preseit known. 



A series of optically active amylamines is described iu Compt. 

 rend, by ^L Plimpton. The e compounds are obtained from 

 amyl bromide — from active amylic alcohol — by the action of 

 alcoholic ammonia. 



In Chan. Centralblatt E. Ludwig describes experiments ou 

 the localisation of arsenic, absorbed as arsenious oxide, in the 

 animal organism : contrary to the results of many former expeti- 

 menters, Ludwig asserts that an accumulation of arsenic occurs 

 in the liver : neither the bones nor the brain retain ar»enic for 

 any length of time. Ai-senic was detected in the liver of a dog 

 forty days after the last dose had been administerei, but no trace 

 could be found in the brain, bones, or muscles. Ludwig's 

 results are generally confirmed by Johnson and Chittenden 

 (Amer. Client, yoi/ni.). 



MM. des Cloizeaux and D.\mour describe {Compt. rend.) 

 a new selenite of copper, to which they give the name Chalco- 

 ptenite. The mineral occurs in the Argentine Republic, in small 

 green clinorhombic crystals, associated with selenite of lead, and 

 selenite of lead and copper. 



M. Sulliot proposes (Compt. rend.) to employ "chamber 

 crystals " as a disinfectant. He places a solution of these crystals 

 in sulphuric acid in the room or other place to be disinfected ; 

 the atmospheric moisture slowly decomposes the liquid with 

 liberation of o.^ides of nitrogen, which destroy noxious organic 

 matter present in the air. 



Mr. M. W. Williams describes, in C/iem. Soc. Journal, a 

 method for freeing water, to be analysed by the process of 

 Frankland and Armstrong, from nitrates and ammonia. He 

 digests the water with carefully-prepared " copper-zinc couple," 

 whereby all nitrates are reduced to ammonia ; he then distils off 

 ammonia, evaporates to drj'ness, and proceeds in the usual 

 manner. The use of sulphurous acid, which has always been 

 much objected to, is thus obviated. 



In the same journal there is a suggestive paper by Prof. 

 Hartley on the " Relation between the molecular structure of 

 carbon compounds and their ab.orption-sp.ctra." Evidence is 

 accumulated iu favour of the view that the selective absorption 

 exhibited by "aromitic " compounds depends on the vibrations 

 of the carbon atoms within the molecule, but that these atomic 

 vibrations are dependent upon the nature of the molecular vibra- 

 tions themselves, and are probably to be regarded as harmonics 

 of these fundamental vibrations. 



The second and third parts of the Gazclla Chimica Italiana 

 for the present year exhibit very uumistakably the activity of 

 Italian chemi.ts, chiefly in the domain of organic che.nistry. 

 Schiff continues his researches on Glucosides ; the derivatives of 

 thym '1 are studied by Paterno and Ctmzoneri ; Macagno de- 

 scribes experiments on the spectroscopic detection of artificial 

 colouring matters in wines. Koenig, Schiaparelii, Barbaglia, 

 and other known chemists contriljute papers. 



GEOGRAPHICAL NOTES 

 Mr. Edward Whvmper on Monday last addressed a large 

 meeting of the Geographical Society on some features in his 

 recent journey among the Great Andes of the Equator. His 

 paper was not, however, of so popular a nature as those which 

 he read before the Alpine Club and the Society of Arts. The 

 chief facts left on the minds of his very attentive au.Ueiice may 

 be briefly stated Mr. Whymper found by careful experiments 

 that aneroid barometers are not to be depended upon fir the 

 determination of heights, and that there is a remirkable differ- 

 ence in altitudes as fixed by the boiling point of water and the 

 mercur al barometer. He asserted, as the resul: of his o'l.-erva- 

 tions, that it is a mistake to suppose that there are two parallel 

 chains in the Ecuadorian Andes, as u uxlly shown on our maps. 

 This is a point, however, on \vhich mire light is evidently 

 required. Mr. Whymper's account of his ascent of the hitherto 

 unknown peak called Sara-Urcn, was very interesting, and tins 

 achievement alone would stamp him a mountaineer of the highest 

 skill and courage. 



The foUowing award has just been made of the medals given 

 annually by the Council of the Geogi-aphical Society for com- 

 petition amon^ a limited number of public schools :— Physical 

 Geography (Mr. H. N. Moseley, F. K.S., eyaminer) : Gold 

 melal, E. G. Reid, Dulwich College; silver medal, Sydney 

 Edkins, City of London School ; Political Geography (Right 

 Rev. Bishop Abraham, exanvner) ; Gold medal, Theodore 



