260 
NATURE 
utility. After the protracted studies of Froude and Rankine 
in England, published in the Z7yavsactions of the Institution of 
Naval Architects (1861-64), and of MM. Bertin and Bénazé in 
France, the subject may be regarded as exhausted.—On the 
real position to be assigned to the fossil flora of Aix, in 
Provence, by M. G. de Saporta. It is argued against the 
views of M. Fontannes on stratigraphic grounds that the whole 
series of varied and numerous deposits giving birth to the flora 
of Aix, cannot be reduced to the gypsum alone, or to the sec- 
tion of this gypsum contiguous to the beds at Cyrénes. Ina 
further paper it will be shown that the paleontological 
indications are equally opposed to M. Fontanne’s opinion. 
—Note and. photographs of the thunderstorm of May 12, 
1886: spiral form of lightning, by M. Ch. Moussette. 
The photographs taken at Auteuil on this occasion seem 
to indicate a general law that the electrical discharges be- 
tween the clouds and the earth assume the normal form 
of irregular spirals. —Observations of the new planet 259 made 
at the Paris Observatory (equatorial of the West Tower), 
by M. G. Bigourdan.—On the development in series of the 
potential of a homogeneous revolving body, by M. O, Callan- 
dreau. In this paper the author verifies the two formulas of 
Legendre and Laplace relative to the exterior and interior 
points ofa spheroid usually defined by the equation = a(1 + ay). 
—-Memoir on the rowing-vessels of antiquity, by M. Corazzini. 
The author attempts to solve the difficult problems associated 
with the construction of the aves Jonge, and reconstructs the 
Roman polyremes in a manner which seems to harmonise best 
with the monuments and the descriptions of classic writers. —On 
the refraction of carbonic acid and of cyanogen, by MM. J. 
Chappuis and Ch. Riviére. The results of the authors’ 
researches on the refraction of carbonic acid at 21° and up to 
1g atm. are resumed in the formula— 
n — 1 =0'000540f(1 + 0°0076f + 000000504"), 
In which x denotes the index for the ray D, and # the pressure 
In metres of mercury. The refraction of cyanogen has also been 
studied at different temperatures between the pressures of Im. 
and 2m. or 3m. of mercury, the series of experiments relative to 
a determined temperature being resumed in a formula of the 
form 2 — 1 = a(t + 6f).—On the electrical conductivity of the 
mixtures of neutral salts, by M. E. Bouty.—On the decomposi- 
tion of the perchloride of iron by water, by M. G. Foussereau. 
The author had already employed the measure of electric resist- 
ance to determine the nature and proportion of foreign substances 
contained in water and alcohol, and the conditions under which 
these fluids acquire the greatest degree of purity. He now 
applies the same method to the study of the progressive altera- 
tions of fluids, and especially of saline solutions under the influ- 
ence of the dissolvent. The present paper deals specially with 
the perchloride of iron.—Note on a transmitting dynamometer 
with a systemof optical measurement, by M. P. Curie. This appa- 
ratus consists of a horizontal arbor supported by two bearings. 
Two pulleys at the extremities of the arbor serve to transmit 
the motion from the motor to the receiver, and the work done 
is measured during the motion by the torsion of the arbor be- 
tween the two pulleys. —Temperature of the deep waters in the 
Lake of Geneva, by M. F. A. Forel. Ob-ervations taken during 
the years 1879-86 show that at great depths the temperature 
never falls below 4°, and varies normally between 4°°6 and 5°°6. 
From his experiments the author also infers that the heat pene- 
trates to the lower layers mainly through the mechanical inter- 
mingling of the upper with the deep waters under the action of 
the winds. The same explanation, he argues, should be applic- 
able to all lakes and to all seas confined by bars, notably the 
Mediterranean, whose deep waters hive a mean temperature of 
13°.—Absorption spectra of the alkaline chromates and of 
chromic acid, by M. P. Sabatier.—On the heat of transforma- 
tion for vitreous selenium to metallic selenium, by M. Ch. 
Fabre. Vitreous is transformed to metallic selenium by heating 
it to 96° or 97°, the transformation being accompanied by a con- 
siderable development of heat, which is here directly determined 
by means of M. Berthelot’s calorimeter.—Action of vanadic 
acid on the alkaline haloid salts, by M. A. Ditte.—On the 
fluorides of the metalloids, by M. Guntz. By practical tests the 
author has verified his hypothesis that the fluoride of lead is 
decomposable by all the chlorides of the metalloids. With the 
oxychloride of phosphorus the reaction is so regular that it gives 
a convenient process for preparing the oxy fluoride of phosphorus. 
—On the hydrate of baryta, BaO,H,O,, by M. de Forcrand.— { 
A contribution to the study of the alkaloids, by M. CEchsner de — 
Coninck.—Isomery of the camphols and of the camphors, by 
M. Alb. Haller.—Researches on the chemical composition of 
the grease of sheep’s wool, by M. A. Buisine. The grease of 
Australian wool yielded for 100 of dry residuum 71 of acetic 
acid, 4 of propionic acid, 2°6 of benzoic acid, 2°59 of lactic 
acid, 1 of capric acid.—Acidimetric analysis of sulphurous acid, 
by M. Ch. Blarez.—Researches on the development of beetroot ; 
study of the leaf, by M. Aimé Girard. —Comparative studies on 
the influence of the two orders of vaso-motor nerves, on the 
circulation of the lymph, on their mode of action, and on the 
mechanism of lymphatic production, ly M. S. Lewachew.— 
On a process of indirect division by threes of the cellules in 
tumours, by M. V. Cornil.—The house-bug and the seat of its 
fetid secretion: the dorsal abdominal glands of the larva and 
nymph ; the sternal thoracic glands of the adult, by M. J. 
Kiinckel.—On the influence of certain Rhizocephalous parasites 
on the exterior sexual characters of their host, by M. A. Giard. 
—On the circulatory system of the Echinide, by M. R. Keehler. 
—On the seeds of Bondue, and their active principle as a febri- 
fuge, by MM. Ed. Heckel and Fr. Schlagdenhauffen. These 
seeds are supplied by two closely allied exotics: Guélandina 
Bonducella, L. (Cesalpinia Bonducella, Tlem.) and Cesalpinia 
Bonduc, Roxb. Their therapeutic properties are shown to reside 
in the bitter principle, which acts against intermittent fevers as 
efficaciously as the salts of quinine. —On the Triassic system of 
the Eastern Pyrenees, in connection with M. Jacquot’s recent 
communication, by M. A. F. Nogués.—Invertebrate fauna of © 
the Mentone grottoes, Italy, by M. Emile Riviere. In these 
caves the author has discovered 171 species of invertebrates, 
comprising 20 fossil, 125 living marine, and 26 land species, — 
Amongst the living marine species 50 are at once Mediterranean — 
and oceanic, 62 exclusively Mediterranean, and 6 oceanic. 
BOOKS AND PAMPHLETS RECEIVED ‘ 
“A Word for Ireland,” by T. M. Healy (Gill, Dublin).—‘* Inorganic” 
Chemistry,” by Ira Remsen (Macmillan) —‘‘ British Fungi, Lichens, &c.,’" 
by Holmes and Gray (Sonnenschein).—‘‘ Journal of the Mathematical 
Society of St. Petersburg,” vol. vi—‘‘ Outlines of the History of Ethics,’” 
by H. Sidgwick (Macmillan).—‘ Proceedings of the Academy of Natural 
Sciences of Philadelphia,’’ part 1 (Philadelphia).—‘‘ The Handy Guide to 
by W. B. Paton 
Emigration to the British Colonies,” new edition, fe 
vol. viii, No. 3, July 
(S.P.C.K.).—“ Notes from the Leyden Museum,” 
(Brill, Leyden). 
CONTENTS PAGE 
Geology of Turkestan, IT. 2 > 2 2 . 22 2). een 
Chemistry for the Gold-Fields ....... . . 7.) 238% 
Our Book Shelf :— } 
Trouessart’s ‘‘ Microbes, Ferments, and Moulds” . 
Letters to the Editor :— 
Luminous Clouds.—T. W. Backhouse ..... 
Re Immisch’s Thermometer.—G. M. Whipple . . 
Kirby and Spence’s ‘‘ Introduction to Entomology.” 
opm Eieiea my Bossip GO oo OG Oo 
On Variations of the Climate in the Course of Time, 
Il; By Prof Al Blytts% %) 2 fouerl--1 ee ee 
Vegetable Products at the Colonial and Indian 
Exhibition. By John R. Jackson. ....... 
What isa Glacier? By Israel C. Russell... . 
NICS oo a goo oo Bb 4 = 
Our Astronomical Column ;— 
The Strasburg Observatory ......-+.-+4- 
Astronomical Phenomena for the Week 1886 
Julyn8=24) 2 ss a ee Fel pepsi eed ee 
Geographical Notes) % Fey. v0 0st -te en 
The Lunar Surface and its Temperature. 
John Ericsson. (Ji/ustrated) 1... ...+...% 
Scientific Serials) yo) yp snc) oto olen ote 
Societies and Academies. (//lustrated) ...... 
Books and Pamphlets Received ......... 
meee OO > 8 
