Dec. 13, 1888] 



NATURE 



called fl-modification, melting at about 61°. The authors have 

 found (Brit. Assoc. Report, 1887, p. 231) that under this designa- 

 tion two distinct dichloronaphthalftnes have been regarded as one, 

 and now bring forward evidence showing that one of these, 

 melting at 6r'5, is a homonucleal, and the second, melting at 

 64', is a heteronucleal oj3-derivative. They confirm Cleve's 

 view that the dichloronaphthalene, melting at 34°, is a homo- 

 nucleal aj8-compound, the dichloronaphthalene melting at 48° 

 lieing the remaining heteronucleal o3-derivalive. With regard 

 to the constitution of the two homonucleal o6-dichloronaphiha- 

 lenes, the authors show that that melting at 6i°'5 must be the 

 w^-Zrt-com pound (that melting at 34° being, by exclusion, the 

 ortho-derivative), since their experiments prove that so-called 

 a-dichloronaphthalene, melting at 38', and obtained by treating 

 naphthalene tetrachloride with alcoholic potash, is a mixture of 

 two homonucleal dichloronaphthalenes — namely, the oS-deri vative 

 melting at 6i°'5, and the aa-derivative melting at 6S\ Sufficient 

 data have not yet been obtained to determine the constitution of 

 the heteronucleal o;8-dichloronaphthalenes. — Piazine derivatives, 

 by Dr. A. T. Mason. A continuation of the author's work on 

 a class of compounds formerly known as kctines, and more 

 recently as pyrazines. 



Anthropological Institute, November 27. — Francis Galton, 

 F.R.S., President, in the chair. — The President exhibited a gold 

 breastplate from an ancient Peruvian grave.— Mr. F. W. 

 Rudler exhibited a collection of ethnological objects from the 

 Jivaros of the Upper Amazons, and the Arawaks and the 

 Acaways of the interior of British Guiana. — Mr. G. F. F.aA- 

 rence exhibited two Palaeolithic implements from the valley of 

 the Thames, near Erith. — Mr. Osbert H. Howarth read a paper 

 on the ^urvival of corporal penance, and exhibited specimens of 

 the " iUscipHnas," or scourges, which are still used, in public 

 penance, in the village of Fenaes d'Ajuda, a remote community 

 on the north coast of St. Michael's, Azores. — The Secretary 

 read a paper by the Rev. Benjamin Danks on marriage customs 

 of the New Britain Group. 



Paris. 

 Academy of Sciences, December 3. — M. Daubree in the 

 chair. — Observations of the minor planets made with the great 

 meridian instrument of the Paris Observatory during the fir.-t 

 half of the year 1888, by M. Mouchez. The right ascension 

 and polar di-lance, with correction of ephemerides, are tabulated 

 fir Diana, Danac, Athamantis, Astrea, Parthenope, Flora, 

 Sappho, Hebe, Cyrene, Germania, and five other minor planets. 

 — On the satellites of Mars, by M. H. Poincare. The paper deals 

 with M. Dubois's recent hypothesis (Ct'w/to rendus, August 20, 

 1 888), that Phobos and Deimos were originally small planets, 

 which a few years ago passed within the attraction of Mars. 

 This hypothesis, which is based on the fact that the two satel- 

 lites were never observed before 1877, is shown to be inadmis- 

 sible by a Consideration of the eccentricity of the orbit of Mars, 

 and on other grounds. Although the eccentricity of Mars is 

 about six times greater than that of the earth, it can be demon- 

 strated that the elements of its moons cannot have perceptibly 

 varied during the last hundred years. — On the preparation of 

 the phosphorescent sulphides of calcium and strontium, by M. 

 Edmond Becquerel. The author, who has lately resumed the 

 study of these sulphides, now finds that some of the added sub- 

 stances, when employed alone, fail to produce any appreciable 

 effect, and that the simultaneous presence of several is some- 

 times necessary for the preparation of strongly luminous bodies. 

 The modifications depend not only on the nature of the mixed 

 substance?; but also on that of the phosphorescent sulphide 

 itself. — On the invariants of difTerential equations, by M. E. 

 ,( Goursat. Since M. Halphen's researches on linear differential 

 £ equations, M'. Appell and others have extended the notion of 

 \ invariants to differential equations of a more or less general form 

 "^ for certain special categories of transformations, without, how- 

 i ever, determining in a general' way the existence of these in- 

 -; variants. The determination is here effected by a demonstra- 

 tion based on Herr Lie's Tlicoric der Transformationsgritppen, 

 (Leipzig, 1888). — On the dark waters of the equatorial regions, 

 by MM. A. Munt^ and V. Marcano. For the purpose of 

 ascertaining ihe cause of the dark colour so characteristic of 

 numerous affluents of the Amazons and Orinoco, the authors 

 have analyzed some specimens from the upper course of the 

 latter river. They conclude that the discoloration is due to the 

 fr.ee humic acids held in solution, and derived from the decom- 

 l"osition of vegetable matter on a granite soil free from lime. 



The liquid is thus in some respects of the nature of bog-water, 

 and the colour persists because, in the absence of lime, the 

 phenomena of nitrification, and consequently the combustion of 

 the organic matter, cannot take place, as shown by the complete 

 absence of nitrates. The waters themselves are perfectly limpid, 

 wholesome, and palatable, for although the discoloration is 

 primarily due to their chemical composition, its intensity must 

 be attributed to phenomena of reflection produced by the great 

 depth of the liquid masses.— On the benzoic acetals of mannite 

 and its houologues ; decomposing action of benzoic aldehyde, 

 by M. J. Meunier. The acetal of mannite is readily obtained 

 by dissolving it in hydrochloric or sulphuric acid, adding a cor- 

 responding quantity of benzoic aldehyde and shaking ; the mix- 

 ture is rapidly transformed to acetal and solidifies. When a 

 benzoic acetal, and doubtless others also, is completely freed 

 from the excess of aldehyde, it resists the action of the acids as 

 well as of the alkalies, and is not decomposed by prolonged boil- 

 ing with acidulated water. In the presence of the aldehyde, on 

 the contrary, decomposition takes place very rapidly by boil- 

 ing, and all the more rapidly the greater the excess of aldehyde, 

 even if the liquid be but slightly acidulated, containing, for in- 

 stance, not more than i per cent, of sulphuric acid. Benzoic 

 aldehyde thus influences the hydration of the acetal and the 

 consecutive formation of mannite. — Action of the sulphide of 

 carbon on clays ; production of the oxysulphide of carbon, by 

 M. Armand Gautier. During his researches on the mineralizing 

 elements of thermal waters, the author has been led to attempt 

 the synthesis of the oxysulphide of carbon by causing the 

 vapours of the sulphide of carbon to act at red heat on the 

 natural silicates, and especially on the argillaceous earths. 

 These essays have been successful, and a method is here 

 described which alone can furnish the oxysulphide of carloi, 

 COS, in a pure state and in large quantities — Transformation 

 of terpilene into a menthene, by MM. G. Bouchardat and J. 

 Lafjnt. By exposing terpine, C2(,Hj6,2Hj02, for fifteen hours 

 at 100° C. to twenty times its weight of aqu:ous hydriodic acid 

 saturated at 0°, the authors b.ave produced a dihydriodate of 

 crystallized terpilene, C.j„Hj«,2HI, identical with the dihy- 

 driodate of the essence of terebinthine. From their further 

 researches they conclude that natural menthol should perhaps 

 be grouped with the terpilene series. — On a j^permaceti whale 

 taken in the Azore waters, by Prince Albeit of Monaco. Photo- 

 graphs are given of the head of a large spermaceti whale har- 

 pooned last summer in the neighbourhood of the Azores. It 

 measured from the eye to the upper extremity of the mouth I -90 

 metre, and from the under jaw to the lip I 16 metre. —Papers are 

 contributed by M. G. Saint-Remy on the brain of the spider 

 family ; and by M. A. Giard on Peroderma cylindricum, Heller, 

 a parasite of the sardine. 



Berlin. 

 Physical Society, November 16.— Prof, du Bois-Reyraond, 

 President, in the chair.— Prof, von Bezold made a further com- 

 municatioB on the thermo- dynamics of the atmosphere, in con- 

 tinuation of a statement made to the Society earlier in the year. 

 After briefly recapitulating the processes which occur during the 

 adiabatic expansion of a' mass of air as it rises, he intrr)duced 

 intothermo-dynamic considerations a new idea, brought forward 

 by Helmholtz, and found to be extremely convenient. The idea 

 is that of " potential temperature," or in other words the absolute 

 temperature assumed by a mass of air when it comes adiabati- 

 cally under normal pressure. The speaker then propounded the 

 following as a general law : " Whenever a mass of air changes 

 its condition adiabatically, the potential temperature is never 

 diminished, it is usually increased, and sometimes is unchanged." 

 This law was proved from a number of examples. During the 

 adiabatic alterations of pressure and volume in the curretrts of 

 air as they rise and fall, the temperature should fall, on the 

 average, about l" C. for a height of 100 metres ; as a matter of 

 fact, the fall is really less than i° C. This is due to the fact 

 that under natural conditions the processes do not occur adia*^ ati- 

 cally, since near the earth's surface and above the level of the 

 clouds warming and cooling influences are brought to bear on 

 the air. In an anticyclone the powerful radiation from the earth 

 leads to a cooling of the lower strata of air, and to this is due the 

 fall of temperature observed at all stations which are situated on 

 a height, a phenomenon which, according to the speaker, must 

 also make its appearance at lower levels during maximal pressures 

 of the air in winter and during the night. In cyclones the fall of 

 temperature with increasing altitude similarly differs from its 

 theoretical value, since warm air from the neighbouring anti- 



