412 



NATURE 



{Feb. 26, 1880 



In a spectrum there is less fear of indistinctness from super- 

 position of images than in a telescope, but a greater amount of 

 focussing is required with unachromatic lenses, insomuch that 

 lines in the field at one time need alteration to obtain distinctness. 

 Moreover it is an obvious advantage to transmit the whole of the 

 rays coming from the collimator as nearly as possible parallel 

 through the intra objective space and the prisms. The object 

 glasses were made by Mr. Ahreas about four years ago, and sent 

 to Prof. Macleod. They were put aside but have been recently 

 re-mounted, owing to Mr. Cornu having recently published a 

 similar device. A paper on an automatic switch for telephone 

 circuits was then read by Dr. Wynne. The object of the switch 

 was to enable any client of a telephone exchange to communicate 

 with any other through the central office without the need of an 

 assistant at the office. Mr. Varley and Frof. Ayrton criticised 

 the device and the latter thought that the contacts might not be 

 always reliable. Profs, Ayrton and Perry then read a note on 

 their theory of terre-trial magnetism. Prof. Rowland of 

 Baltimore had pointed out an error in their calculation which 

 vitiated their results, and they therefore admitted that the charge 

 statical electricity on the surface of the earth, assumed by them 

 as competent to account for the earth's magnetism, was not 

 sufficient to account for the whole but only a portion of that 

 magnetism. Nevertheless they thought that the changes in the 

 distribution of such a charge due to changes in the condition of the 

 dielectric medium between the earth and the sun, might account 

 for the observed perturbations in the magnetic elements. 



Statistical Society, February 17. — Sir Rawson W. Rawson, 

 CD., in the chair. — The busine.-s of the evening was the reading 

 and discussion of a paper by Mr. Thomas A. Welton, on certain 

 changes in the English rates of mortality. 



GiJTTIN'.EN 



Royal Academy of Sciences, January 10.— The following 

 among other papers were read: — On some Indo-Germanic, 

 especially Latin and Greek, numerals, by Herr Benfey. — 

 Remarks on some Thracian and Maesian coins, by Herr Wieseler. 

 — The chronology of Julius Africanus, by Herr Trieber. — Report 

 on the polyclinic for ear diseases, by Dr. Bitrkner. 

 Paris 



Academy of Sciences, February 16. — M. Edm. Becquerel in 

 the chair. — The following papers were read : — Meridian obser- 

 vations of small planets at the Greenwich and Paris observa- 

 tories during the fourth quarter of 1879, communicated by M. 

 Mouchez. — Determination of the difference of longitude between 

 Paris and Bregenz, by MM. Lcewy and Oppolzer. The difference 

 between Paris Observatory and the station of Pfender on a 

 mountain near Bregenz (which is about the most western point of 

 Austria) was found oh. 29m. 45 - l4s, (By Pfender Austria was 

 already connected with Germany, Italy, and Switzerland.) The 

 operations are described. — Studies on persulphuric acid ; its 

 formation by electrolysis, by M. Berthelot. He has got liquors 

 containing 123 gr. of the acid (S 2 7 ), but this could not be 

 exceeded or ea>ily maintained, the rate of spontaneous decom- 

 position becoming equal to that of formation. The liquor also 

 contained 375 gr. sulphuric acid, and 850 gr. water. For these 

 results, dilute sulphuric acid(S0 4 H + 10 HO, e.g.) is electrolysed 

 in a porous vessel surrounded by a concentric vessel holding the 

 same liquid. The liquids are cooled by water flowing in interior 

 serpentines. The electrodes are large platinum wires projecting 

 2 or 3 ctm. from glass tubes, and six or nine Bunsens are used. (The 

 electrolytic phenomena are studied). Persulphuric acid left to 

 itself is' destroyed gradually and wholly. Agitation, or rise of 

 temperature, promotes decomposition ; also diminished dilution. 

 — Note on new derivatives of nicotine, by MM. Cahours and 

 Etard. An isomer of dipyrniine (isodipyridine) is obtained by 

 a certain treatment of thiotcirapyruiine. — Evolution of inflor- 

 e cence in the Gramhuw (3rd part) ; order of appearance of the 

 frst vessels in Phlatm, Cynosiints, Poa, by M. Trecul.— On the 

 divisions of cyclotomic functions, by Prof. Sylvester. — Equations 

 of the small oscillations of an inextensible wire in motion in 

 space, by M. Leaute. — On the linear differential equations with 

 doubly periodic coefficients, by M. Picard. — On the same, by M. 

 Mittag-Lelfler. — On the hypergeometric series of two variables 

 and on linear differential equations with partial derivatives, by 

 M. Appell. — On Legendre's law of reciprocity extended to 

 numbers not prime, by M. Genocchi. — On the impossibility of 

 the algebraic relation X" + Y" + Z n = o, by M. Korkine. — On the 

 approximation of circular functions by means of algebraic functions, 

 by M. Laguerre. — On new fringes of interference, by M. Gouy. 

 A collimator, with slit horizontal, and a telescope, are placed in 



line, and between them a glass trough containing half water, half 

 saline solution, diffusion having been allowed a few minutes. 

 Light being transmitted, a series of fringes appears in the tele- 

 scope, owing to variation in the index of refraction through dif- 

 fusion, causing the plane wave to -be no longer plane after 

 traversing the trough. M. Gouy proposes to study the progress 

 of diffusion by means of these effects. — On the density of some 

 gases at a high temperature, by M. Crafts. He describes some 

 results with his improved apparatus, having experimented with 

 ammonia, carbonic acid, hydrogen, hydrochloric acid, &c. 

 For the last named a normal density was obtained at the 

 highest temperature of the furnace. — Action of water on fluoride 

 of silicium and fluoride of boron ; dissolution of cyanogen in 

 water, by M. Hammerl. Numerical results for the heat liberated 

 are given. — Reproduction of amphigene, by M. Hautefeuille. 

 Vanadate of potash which (as formerly indicated) may replace 

 alkaline tung-tates and phosphates in preparation of felspars, 

 furnishes crystals having the form and composition of amphigene 

 whenever the mixture of silica and alumina treated contains a 

 large proportion of alumina. The density of artificial amphigene 

 is 2 '47 at 13 , that of amphigene 2*48 (Damour). — On the 

 martite of Brazil, by M. Gorceix. By the hypothesis of altera- 

 tion of pyrites he explains certain facts of pseudomorphism and 

 filling up, ob c erved in certain metamorphic rocks of the province 

 of Minas ; also the disappearance of iron pyrites in auriferous 

 itabintes, where gold has for gangues ordinary or arsenical 

 pyrites. — Experimental researches on the phosphorescence of 

 Lampyris, by M. Jousset de Bellesme. He removed the cephalic 

 ganglions, to abolish all spontaneous phosphorescence, then 

 stimulated electrically. He could always thus produce phos- 

 phorescence if oxygen was present. He shows reason for 

 thinking that the phenomenon is a chemical one, but produced 

 in Lampyris only under biological conditions. It is of the same 

 order as muscular contraction, or liberation of electricity by 

 the torpedo, which are doubtless due to chemical combinations 

 effected in protoplasmic matter. The phosphorescent sub- 

 stance is probably gaseous, and phosphoretted hydrogen. 

 The author is led to regard phosphorescence as a general 

 property of protoplasm, consisting in liberation of the gas just 

 named. — Researches on the action of salicylic acid on the respira- 

 tion, by M. Livon. First retardation, then acceleration, then 

 retardation and stoppage. — The temperature of frozen lakes, by 

 M. Forel. The depths reached by Mr. Buchanan (Nature, 

 vol. xix. p. 421) were not sufficient to cover the limit of surface 

 cooling, which may descend to 110m. (Lake of Zurich). The 

 penetration of cold is very gradual and progre-sive. A layer of 

 ije on Lake Morat was found absolutely to stop the cooling, and 

 the water, under ice forty days, underwent an equalisation of 

 temperature, far, however, from complete uniformity. — Tor- 

 rential deltas, by M. Desor. These deltas will have to be dis- 

 tinguished more than has hitherto been done from the deltas of 

 afreat rivers. 



CONTENTS Tags 



The Second Yarkand Mission 389 



Cryptogamic Flora of Silesia. EyW. R. McNab 3./ 1 



Our Hook Shelf:- 



Landauer's " Blowpipe Analvsis " :<- 



" The Zoological Record for 1S77 " 392 



Letters to the Editor: — 



Sunshine Cycles — E. Douglas Archibald ;93 



The "Gastric Mill" of the Crayfish.— W. E. Roth (With Illus- 

 trations) 395 



Modern Chromatics.— Prof. Ogden N. Rood; S. P. T 395 



Etna— G. F. Rodwkll 33* 



Ice-Crystals and Filaments.— Rev. O. Fisher ; Prof. D. Wetter- 



han 396 



" Scientific Jokes."— G. H 39 6 



Tidal Phenomenon on Lake Constance.— Samuel James Cui-fr 307 



Meteors in New Caledonia.— Consul E. L. Lavard 397 



Intellect in Brutes.— Alex. Mackennal; W. Brown . ... 397 

 The Artisan Reports on the Paris Exhibition of :87s. By Prof. 



Si lvanbs P. Thompson • • ■ ■ 397 



How to Colour a Map with Four Colours. By A. B. Kempe . 399 



The Lipari Islands. Bv G. F. Rodwell (H'ith Illustration) . . 400 



Something about Milk" -to? 



Artificial Production of Diamonds -t°4 



The History of Writing, II. By Prof. A. H. Sayce 404 



Notes . * a % 



Physical Notes 4 ' J5 



Geographical Notes .■•■49 



A Strange Phenomenon • ' 4< '- ) 



The New Hydrogen Linesodserved by Photography, the Star 

 Lines, and the Dissociation of Calcium. By Dr. H. W. 



Vogel *" 



University and Educational Intelligkncb 4" 



Societies and Academies 4 " 



