96 
NATURE 
_ [Way 27, 1886 
ap ears tu be exercised by a point situated to the north of Nice 
in the Alps.—-On the barometric pressure of May 13, 1886, 
when at 4 o'clock in the morning the barometer fell to 
737°37 mm., the lowest recorded in Paris since the year 1757, 
by M. E. Renou. This remarkable fall coincides with violent 
atmospheric disturbances in Madrid and other parts of Spain, 
in England and the United States. The stormy weather 
reached Italy and Germany on May 14, when the Jura and 
Chaux-de-Fonds were covered with snow.—Action of vanadic 
acid on the ammoniacal salts (continued), by M. A. Ditte. In 
this paper the author deals with a second group comprising the 
sulphate, chromate, iodate, borate, acetate, vanadate, per- 
chlorate, carbonate, and hydrochlorate of ammonia.—On 
several double silicates of alumina, and of potassa or soda, 
by M. Alex. Gorgeu. The kaolin with which these silicates are 
obtained is that used at the Sevres works. This composition 
when dried at a temperature of 120° C, is almost exactly that of 
the silicate of hydrated alumina, 2Si0,A1,03,2110. Its action is 
described on the alkaline haloid salts, on the alkaline carbonates, 
and on the fused caustic alkalies.—On the combinations of the 
chloride of zinc with water, by M. R. Engel. Besides that dis- 
covered by M. Schindler, the author describes three other 
hydrates of the chloride of zinc, of which two may be obtained 
in large isola ed crystals. —On a combination of phosphuretted 
hydrogen with the hydrate of chloral, by M. J. de Girard. —On 
pilocarpine, by MM. E. Hardy and G. Calmels. For this 
substance the authors have established the formula— 
jC00 CH, 
(C;H,N)B—C. —N—CHs 
\cH, SCH, 
and for pilocarpidine— 
; CORE Cis 
(C;H,N)B—C Ne 
CH, s 
—Researches onthe composition of carotine, its chemical function, 
and its formula, by M. A. Arnaud. This is a carburet of hydro- 
gen (Cy,H4g) identical with the orange-red crystallised substance 
which the author has extracted from the leaves of various kinds 
of plants. This colouring-matter exists also in a great many 
fruits, and especially in the tomato, and may in fact be said to 
be universally present in the roots, leaves, and fruits of plants. 
It oxidises in the air even at the ordinary temperature, and 
especially about 70° C., and in solution this oxidation becomes 
extremely rapid. Remarks on the bilobites, by M. Stan. Meunier. 
The author makes a fresh study of these interesting vestiges, 
without deciding the question whether they are mere animal 
footprints, as supposed by M. Nathorst, or real fossil algze, as 
maintained by MM. Delgado and De Saporta.—Characteristics 
of the stem of Poroxylon (fossil gymnosperms of the Carboni- 
ferous epoch), by MM. C. Eg. Bertrand and B. Renault.— 
Account of a meteor recently observed on board the steamer 
Algérie in the Gulf of Smyrna, by M. L. Aubouy. 
BERLIN 
Physiological Society, April 30.—Dr. Wolffberg spoke on the 
Young- Helmboltz theory of the colour-sense, which he extended 
in the direction of assuming the existence of red-sensitive, green- 
and violet-sensitive ganglia in the central organ of sight-percep- 
tion in the sphere of vision. These ganglia were connected with 
the red nerves, the green nerves, and the violet nerves, and by 
means of such nerves communicated with the retina. Seeing, how- 
ever, that yellow, blue, and white were likewise psychically simple 
sensations, Dr. Wolffberg assumed specific ganglia for these as 
well, which, however, stood in connection with the red, green, 
and violet ganglia, the yellow ganglia being situated at an equal 
remove from the red and green, but at a further remove from 
the violet ganglia. Similar was his conception of the situation 
and connection of the blue and white ganglia. Regarding the 
sensation of black, he would speak in an address in the imme- 
diate future. —Dr. Uhthoff made further communications respect- 
ing the dependence of visual sharpness on the intensity of illu- 
mination. After an historical survey of the older experiments to 
determine the relation of visual sharpness to light intensity, he 
described the results of his own labours in this field. In the 
case of white light, he had communicated the relation on a former 
occasion (NATURE, vol. xxxi. p. 476). In the case of yellow 
light, the visual sharpness under low intensities increased just as 
| I'Académie Impériale des Sciences de St. Petersburg,” vol 
rapidly with increasing intensity of light as in the case of white 
light.” The curve, however, in the former case attained a greater 
height than it did with white, and then likewise proceeded 
parallel to the abscissa. With red light, on the other hand, the 
curve kept below the height reached with white light ; it rose 
slower, moreover, and never became parallel. The curve of 
visual sharpness for green light lay still deeper than for red, and 
also rose persistently, though slowly. | The curve for blue light 
lay deepest of all, and very soon became parallel to the abscissa 
of the light intensity. In the case of a green-blind person, the 
curves for white, yellow, and red were the same as in the case 
of the normal eye, as there was likewise a coincidence for 
blue. The curve for green fell almost coincident with the 
low curve for blue. 
BOOKS AND PAMPHLETS RECEIVED 
“Contra-Indications for Visiting the High Altitudes,” with a De- 
scripti n of the Environs of Maloja, by Dr. A. T. Wise (Churchill). 
—The Pictorial Arts of Japan,” part ii., by Wm. Anderson (S. Low). 
— Bees and Bee-keeping,” part ix., by F. R. Cheshire (U. Gill).— 
“Fancy Pigeons,” 3rd edition, part ix., by J. C. Lyell (U. Gill).— 
“ Bricish Cage Birds,” part ix., by R. L..Wallace (U. Gill).—‘ Bicycles and 
Tricycles of the Year 1886,” by H. H. Griffin (U. Gill). —‘‘ Mineralogical 
Magazine,” March.—‘ Journal of Physiology,” April.—“ Proceedings of 
the Physical Society, St. Petersburg,”’ vol. xviil. part 4.— Bulletin de 
xxxi. No. 1.— 
“Chemical Atlas,” part 1, by C. Peddie (Thin, Edinburgh).—‘*The Baths, 
Bathing, and Attractions of Aix-les-Bains,” by Dr. W- Wakefield (S. Low). 
— Bulletin of the United States Fish-Commission,” vol. v., for 1885 
(Washington) —‘‘ Causeries Scientifiques,”’ by Hy. Vivarez (J. Michelet, 
Paris).—‘* Proceedings of the i Philosophical Society,” April.— 
American 
“ American versus English Methods of Bridge Designing” (Japan Mail).— 
“Third Report on the Chemical Composition and Physical Properties of 
American Cereals, Wheat, Oats, Barley, and Rye,” by C. Richardson 
(Washington).—‘‘ Memoir of Arnold Guyot, 1807 to 1884,” by J. D. 
Dana. 
CONTENTS PAGE 
A Hand-Book to the History of Philosophy. ByJ. S. 
Haldane oye olen” Rechte ie) moVerseede ese 5 73 
Electricity Treated Experimentally ....... 74 
Our Book Shelf :— 
Eagles’s ‘Constructive Geometry of Plane Curves”. 74 
“Scientific Memoirs by Medical Officers of the Arm 
of India,’?—Dr! E; Klein, FR:S: © 3... nee 
Letters to the Editor :— 
On the Thomson Effect as Expounded by Prof. Tait. 
—Prof: J. D. Everett, FORSS. (2). 2. ose 
Scientific Nomenclature.—George M. Minchin 76 
Pendulum Oscillation —M. H.Maw....... 76 
What is Histioderma?—A. Ramsay ; Dr. J. Victor 
Carus... 2 00 2a Be ee eiiee Ce 
Black Skin:-—F. CG: J. Sputrell) 72 <2) seem) 
Male Animals and their Progeny.—P. . ...... 76 
Birds and Mirrors.—F. C. Constable .... 76 
Surgeon-Major T),R) Lewis > = 2. = -) ae een 
A Sketch of the Flora of South Africa. . ..... 77 
The International Committee of Weights and 
Measures 25.0 ob Goel ec es lence, ou sue) ose nen 
The Weather of the Ice Saints’ Festivals of 1886 . 79 
Cretaceous Metamorphic Rocks ......... 80 
The Composition of the Edible Bird’s-Nest (Co//o- 
calia nidifica). By Jos. R. Green, (J/lustrated). . . 81 
Notes 2.02 Ru 2202 ee © cht, einen 
Our Astronomical Column : 
The Heliometer of the Yale College Observatory . . 84 
Eclipse of Jupiter’s Fourth Satellite ........ 
A New Comet .... 
for. ‘the. Week 5 1886 
Astronomical Phenomena 
May go-Juners ye ee eis) eae co el ee 
Geographical Notes .... ¢ Beat cit ‘0 85 
Telescopic Objectives and Mirrors: their Prepara- 
tion and Testing. By Howard Grubb, F.R.S.. . 
Indian Castings at the Indian and Colonial Exhibi- 
ti6m, 205 SF ey ete selec hte eeu eet em 
A New Spectrometer, By J. E. A. Steggall. . . . 
The Abacus in Europeandthe East. ....... 
The Gazetteer of Russia ......... 
University and Educational Intelligence ..... 
Scientific Serials By Gh MDAC is Geiowce DOLD Oo 
Societies sand/Academiesi.u-) . ere anole 
Books and Pamphlets Received . 
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