9 6 



NA TURE' 



[Nov. 27, 1884 



sarily produce true cholera in man. — On the presence of 

 the biliary salts in the blood of cholera patients, and on 

 the existence of a toxic alkaloid in their dejecta, by M. 

 G. Pouchet. The author, who is conducting a series of 

 important experiments in the Hospital of Saint-Louis, Paris, 

 concludes, so far, that the blood of cholera victims is cer- 

 tainly charged with a proportion, occasionally very consider- 

 able, of biliary salts, while their dejecta nearly always possess 

 a strong alkaline reaction. — Letter on the application of the 

 decimal system to the measurement of angles and of time, by 

 the Minister of Public Instruction and the Fine Arts. — On a 

 generalisation of the theory of mechanical quadratures, by M. 

 Stieltjes. — On the reduction of the Abelian integrals, by M. II. 

 Poincare. It is shown that any system of Abelian integrals 

 always differs infinitely little from a reducible system. — Note on 

 the involution of superior dimensions, by MM. J. S. and M. 

 N. Vanecek. — Note on an equation analogous to Kummei-'s 

 equation, by M. E. Goursat. — A fresh demonstration of a theory 

 of Jacobi respecting the decomposition of a number into four 

 squares, by M.M. Weill. — On the laws of friction in mechanical 

 appliances in connection with the experiments on the electric 

 transmission of force about to be made between Paris and Creil, 

 by M. Marcel Deprez. — On the construction of prototype stand- 

 ards of the legal ohm, by M. J. Rene Benoit. The Inter- 

 national Conference of 1SS4 having defined the value of the legal 

 ohm, the author describes some quicksilver standards representing 

 the new unity constructed by him at the request of the Minister 

 of Posts and Telegraphs. — Note on the indices of refraction of 

 crystallised alums, by M. Ch. Soret. — On the chemical con- 

 stituents of the rain-water that falls in the city of Algiers, by 

 M. Chairy. — Remarks on the combustible carburetted com- 

 pounds present in the terrestrial atmosphere, by MM. A. Muntz 

 and E. Aubin. — Note on the trifluoride of arsenic, by M. H. 

 Moissan. — On the reaction of ferric oxide at a high temperature 

 on certain sulphates, by M. Scheurer-Kestner. — On ammoniacal 

 ferment, by M. A. Ladureau. The author gives the results of 

 experiments commenced three years ago for the purpose of 

 determining the n'le and presence of this substance in Nature. — 

 On the presence of amylase in the leaves of plants, by M. L. 

 Brasse. The author has determined the presence of amylase in 

 all leaves hitherto examined by him, including the potato, 

 dahlia, maize, beetroot, tobacco, poppy, sunflower, &c. — On 

 the employment of the cultivated yeast of wine for stimulating 

 fermentation and shortening its duration, by M. A. Rommier. 

 — Addition to a note on a crystallised pegmatite of chloro- 

 phyllite from the banks of the Vizezy, near Montbrison, by 

 M. F. Gonnard. 



Berlin 



Physical Society, October 24. — In former experiments with 

 Helmholtz's leucoscope Dr. Konig had found that, while persons 

 having normal trichromatic eyes saw the two images appearing 

 in the field of vision differently coloured whatever the position 

 in which the Nicol prism was placed, persons with so-called 

 colour-blind or bichromatic eyes, on the Nicol prism being 

 placed in a certain position, saw similar images. In the case of 

 all so-called red-blind individuals the position of the Nicol 

 prism was always the same, and differed from that in which 

 green-blind persons saw like images. The leucoscope was, 

 therefore, an instrument by means of which colour-blindness 

 could be conclusively determined. For the practical require- 

 ments of eye-doctors, Dr. Konig had now so far simplified the 

 leucoscope that it contained only a double prism, a lens, a quartz 

 plate (of 5, 10, or 15 mm. thick), a Nicol prism, and a telescope. 

 With the help of this simple instrument not only did it become 

 eisy to ascertain colour-blindness in practice, but it could like- 

 wise be determined whether any transitions occurred between 

 red and green blindness. Among fifty colour-blind persons 

 examined by Dr. Kong, he had not found a single case 

 of such transitional form. — Prof. Neesen reported on the re- 

 sumption of his earlier experiments regarding the influence of 

 magnetisation on the electrical conductivity of fluids. The fluid 

 conductor consisted of two tubes, a longer and a shorter, to 

 which the current was transmitted by means of electrodes exactly 

 alike. The tubes were combined into a bridge, and counter- 

 balanced by the intercalation of metallic resistances. One tube 

 was brought between the armatures of an electro-magnet, and 

 the resistance measured alternately with and without the excited 

 electro-magnet. When the tube was placed equatorially between 

 the magnetic poles, the difference in the balance of the galvano- 

 meter was not greater than that produced on the galvanometer 



by the magnetising current alone (o - 3 parts of the scale). 

 With the tube placed in the axial position, on the other hand, 

 the difference in the balance under an excited electro-magnet 

 amounted to about 1 part of the scale, an effect which seemed 

 to demonstrate a positive influence exercised on the conductivity 

 by the magnetism, considering that the electro-magnet employed 

 was not very powerful. It still remains necessary, of course, to 

 determine by special experiments whether this change of resist- 

 ance does not proceed from the influence exercised by the mag- 

 netism on the polarisation of the electrodes.' — Dr. Kayser pro- 

 duced the lightning-photograph he had lately shown to the 

 Meteorological Society (vide Nature, vol. xxx. p. 652), and 

 thereby gave rise to a somewhat lengthy discussion on light- 

 ning-discharges. — Prof. Eilhard Wiedemann of Leipzig commu- 

 nicated some results of an examination he had made into 

 colloids, the relation of which to water, following up an earlier 

 work on crystals and crystalloids, he determined with respect to 

 their thermal behaviour. Lime on being brought into contact 

 with water swelled, as was known, and that with evolution of 

 heat. On dissolving slacked lime, on the other hand, in a 

 larger quantity of water, heat became latent. Similar rela- 

 tions applied to other organic colloids, such as ge'atinej 

 starch, albumen, &c. The expansion of gelatine under heat 

 Prof. Wiedemann found to be quite regular. At the melting- 

 point of the colloids the curve of expansion showed only a very 

 slight curvature convex to the abscissa? of temperature. When 

 Prof. Wiedemann put some gelatine in a test-glass, and put 

 on the top of it some small shot, and furtlnr placed a 

 layer of gelatine over that, he saw, after heating, the shot 

 slowly sink through the viscid mass to the bottom. If he now 

 again spread some small shot on the top of the fluid gelatine, 

 he again saw it sink slowly downwards. As soon, however, as 

 it reached the place occupied by the previous shot before it 

 sank to the bottom, its descent became much more rapid, as 

 though the first shot had opened up a channel of lighter consist- 

 ence in the gelatine which had been originally of the same con 

 sistence as the superincumbent gelatine. 



CONTENTS page 



Over-Pressur? in Elementary Schools. By Dr. J. H. 



Gladstone. F.R.S ' 73 



The Distribution of the Meteorological Elements in 



Cyclones and Anticyclones 75 



"Flatland." By R. Tucker 76 



Our Book Shelf.— 



Lynn's " First Principles of Natural Philosophy " . . 77 

 "Elements de Mecanique, avec de nombreux Exer- 



cices " 78 



Letters to the Editor : — 



Chemical Research in Great Britain. — Prof. W. N. 



Hartley 7$ 



Our Future Watches and Clocks.— Ernest G. 



Harmer ; R. B 80 



Lightning-Conductors.— Col. Arthur Parnell ... So 

 Government Scientific Books. — W. Budden .... Si 

 Peculiar Ice Forms.— Dr. John Rae, F.R.S. ... Si 

 Fly-Maggots Feeding on Caterpillars.— F. N. Pierce 82 

 Birds-Nest Soup. — Consul &. L. Layard ... 82 



The Prime Meridian Conference 82 



On the Interference-Curves known as " Ohm's 



Fringes." By H. G. Madan S3 



Continuous Automatic Brakes. (Illustrated) .... 84 

 The Galvanometer of d'Arsonval and Deprez. 



(Illustrated) 86 



The Basalt-Fields of New Mexico. By Arch. Geikie, 



F.R.S., Director-General of, the Geological Surveys .if 



r the United Kingdom; Capt. C. E. Dutton, U.S. 



Geological Survey 88 



Notes .....' 89 



Our Astronomical Column : — 



The Eclipse of Thucydides, B.C. 431, August 3 . . . 91 



Wolf's Comet 9' 



Minima of Algol 9 1 



The Wave Theory of Light. By Sir William Thom- 

 son, F.R.S., LL.D. (Illustrated) 9' 



University and Educational Intelligence 94 



Scientific Serials 94 



Societies and Academies 95 



