76 



NA TURE 



[May 28, 1874 



(not to prolong our enumeration) are the constitution of chlorhy- 



dric acid and its salts (Thomsen), new sulphur salts (Schneider), 

 and the volume constitution of some oxides (Schroder). — The 

 only paper from an English source appears to be that of Pro!. 

 Tyndall's, On propagation of sound through the atmosphere. — 

 A well-executed portrait of Prof. Poggendorff is prefixed to this 

 interesting volume. 



Astyonomische Aachrichteu, Nos. 1,984, 1,985, and 1,987. — 

 These numbers contain a long paper by Prof. E. Kayser on 

 some new applications of the level to astronomical instruments, 

 especially to the alt-azimuth. — A table of the eclipses of 

 Jupiter's satellites, observed at Toulouse from Jan. 4 to 

 April I, appears in No. 1,985. — Observations of planets IJ5 

 and 136, are given by H. G. von der Sande Bakhuyzen, 

 J. Paliser, and E .Stephan. — No. 1,987 contains a paper 

 by C. Hornstein, On the daily variation of the horizontal 

 magnetic force of the earth. The author points out the correspon- 

 dence between the sun-spot period and the variation above men- 

 tioned, the maximum and minimum of each, according to the 

 table, appears to occur at the same time. — R. I^uther gives a 

 number of observations on the positions of the minor planets 

 and variable stars. The elements of Winnecke's comet are 

 given by W. Schur as follows : — 



T = March 14 '0356 Berlin mean time 



a = 274° 7' 5" 



n - 302° 15' 41" 

 i = 31° 32' 26" 



log. q - 9 •947502. 

 Prof. Winnecke communicates the discovery of the above comet. 

 — Prof. Weiss gives an ephemeris of Winnecke's comet I. 

 Position for May 18, R.A. I5h. 22m. 15s., D. -I- 43° 8', de- 

 creasing in R.A. about 15' a day, and increasing in D. a few 

 minutes. — C. Bruhns gives positions of Winnecke's and Coggia's 

 cornels. — Dr. J. Holetschek gives an ephemeris for Coggia's 

 comets as follows : — 



I2h. Berlin time. 



R.A. D. 



h. ra. s. „ , 

 May 23, 6 13 38 -I- 67 21 'o 

 June 4, 5 51 14 -f 63 9-5 

 ,, 16, 5 12 o -(- 47 5-0 

 ,, 28, 4 49 50-1-11 6'i 

 Prof. Peters, A. de Jasparis, and G. BUmher also give observa- 

 tions on the two above-mentioned comets, 



Joiinial dc Physique, April. — This number begins with a note 

 in which M. Desains describes an improved method of studying 

 Newton's coloured rings ; the plane is made movable to and 

 from the lens by means of a fine micrometric screw, so that the 

 pressure can thus be varied ; and the rings are observed with 

 monochromatic light, either direct from a flame, or isolated from 

 the spectrum. — In a paper On transformation of optical achro- 

 matism of object-glass into chemical achromatism, M. Cornu 

 finds that, given an achromatic astronomical telescope, the ob- 

 ject-<;lass of which is formed of a convergent lens of crown glass 

 and of a divergent lens of flint glass, this object-glass may be trans- 

 formed into one capable of giving satisfactorily distinct plioto- 

 graphic images, by separating the two lenses to an extent 

 dependent on the nature of the two glasses. With the glasses 

 used in optics, a separation of \\ per cent, of the focal distance 

 of the object-glass is sufficient, and the chemical focus is very near 

 the optic focus. The aberrations produced by this separation 

 may, the author thinks, be entirely neglected. Using an excel- 

 lent telescope 100 mm. aperture and i'40m. focal distance, and 

 separating the two glasses 15 mm. he succeeded in photographing 

 a scale, divided into millimetres, placed at 40 metres distance ; 

 the lines were quite distinct ; the relation of the empty spaces to 

 those filled in was quite recognisable, and with a microscope and 

 micrometer it was possible to measure the thirtieth part of the 

 intervals. — This paper is followed by the first part of one in 

 mathematical physics, in which M. Blavier studies the electric 

 resistance of the space inclosed between two cylinders. — A new 

 rheostat is described by M. Crova, in which two platinum wires 

 pass down to the bottom of a long graduateil tube containing 

 mercury, the height of which can be varied through elevation or 

 depression of a spherical vessel communicating with the l)Ottom 

 of ihe glass tube, through a tube of caoutchouc. — There are, 

 further, notices of M. Seebeck's recent researches on motion of 

 sound in bend and bifurcating tubes, M. Dufour's on reflection of 

 solar light at the surface of Lake Leman, &c. 



Bulletin Mensud di la SocUti (f Acclimn'ation de Paris. — The 

 February number of this Bulletin commences with a paper by M. 

 Decroix, on the consumption of horse-flesh in France, as meat, 

 from which it appears that hippophagy is largely on the increase. 

 — The question of silkworm culture again occupies a prominent 

 position in the report, and a statement of the services rendered 

 by acclimatisation in Egypt is very interesting. The Eucalyptus 

 globulus, the cocoa tree, the silkworm, the Cytisus cajan of 

 Madagascar, or Ambrevade, are among the recent acquisitions 

 of that country. — The cultivation of tea in Java is the subject of 

 a valuable paper by M. E. Prillieux ; in 1S26 the first seeds of 

 the tea-]ilant were sown in that island ; and in 1867 the annual 

 production was 1,600,000 lb. The very best qualities often 

 thrive in that country. — The introduction of the African ostrich 

 into France is proposed. The plumage of a male ostrich is 

 valued at from 30of. to 5oof. (12/. to 20/.) ; that of a female at 

 about half that, while the plumage of the American ostrich 

 is sold at I5f. to 2of. the kilogramme (I2j. to ids. per alb.) 

 — The system of oyster-culture, till recently so successfully 

 adopted in France, is threatening to collapse ; and some valuable 

 hints thrown out by M. D. de Mayrc'na may be of service in 

 assisting to arrest the decay. — In the Jardin d'Acclimatation 335 

 mammalia and 2,647 birds were received during January and 

 February, amongst which were a new monkey. Lemur catta, two 

 St. Hubert bloodhounds, some Viellot's pheasants of Java, two 

 emus, a very fine ostrich, and an Indian duck {Anas pacilo- 

 rliyica), a curious-looking bird, with a beak orange at the root, 

 black in the middle, and pure white at the tip ; the plumage is 

 a grey colour. 



Bulletin de V Academie P.oyale de Belgique, No 3, 1874. — This 

 number opens with a tribute to the memory of M. Adolphe 

 Quetelet, in the form of six discourses delivered at the funeral of 

 that eminent savant on Feb. 20 last, by MM. Keyser, Ed. Mailly, 

 cVc, representing various learned Societies. — In the department 

 of Science we find an account of M. Louis Henry's continued 

 researches on diallylic derivatives. In a previous paper he had 

 shown that allylic compounds combine directly with hypochlo- 

 rous acid to produce glyceric compounds ; and he here extends 

 the observation to diallylic compounds, diallyl having been 

 found to combine directly with hypochlorous acid and form a 

 diallylic dichlorhydrine. — In a second note of researches on cam- 

 phor, M. Dubois describes an advantageous mode of preparing 

 brominated camphor. It rests on the previous formation of an 

 additional brominated product, Ci„H,gOBr„ ; which is then 

 decomposed into brominated camphor and bromhydric acid, 

 Ci„Hi5BrO -l-BrH. Among the numerous products obtained 

 from action of iron, heated red, on camphor-vapour, M. Dubois 

 finds a terpene CmHjg, which he regards as important with 

 reference to the composition of camphor. 



Avrliives des Sciences Physiques et A\itui'ellcs, April 15. — This 

 number commences with a chemical paper, by M. Eugene Demole, 

 On distillable oxygenated bases derived from glycol and aromatic 

 amines. It appears that when a primary amine is in presence of 

 oxide of ethylene it is not a molecular combination that is pro- 

 duced, but a true product of substitution of glycol. The secondary 

 base which thus forms possesses still a hydrogen replaceable by 

 alcoholic radicals, and the product of this substitution is a tertiary 

 base ; which, again, is susceptible of the addition of alcoholic 

 iodides to form quaternary iodides indecomposable by alkalis. — 

 In the next paper, M. Dufour studies the phenomenon which 

 occurs when two masses of air, differing in hygroraetric state, are 

 separated by a partition of porous earth ; a diffusion takes place, 

 in which the more abundant current passes from the drier to the 

 more humid air. The activity of diffusion depends on tempera- 

 ture only indirectly, in so far as this occasions difference of vapour- 

 tension on the two sides of the partition. It depends little, if at 

 all, on fraction of saturation. The dItTerence between the quan- 

 tities or tensions of water-vapour on the two sides is the important 

 element ; the diffusion is nearly proportional to this difference. — 

 A spectroscope with fluorescent ocular is described by M. .Soret. 

 The method consists in placing a plate of a transparent and 

 fluorescent substance (uranium glass, or a fluorescent liquid be- 

 tween two thin plates of glass) in the eye-glass of a spectroscope, at 

 the focus of the object glass, and observing the spectrum with an 

 ocular inclined to the axis of the eye-glass. It is specially appli- 

 cable to solar light, and renders distinctly visible the spectrum 

 from H toN, without the necessity of working in a dark chamber. 

 It is less delicate than the photogiaphic method, but much 

 quicker. — M. Achard investigates the action of differential mano- 

 meters with two liquids. 



I 



