430 
NATURE 
[ Sept. 2, 1886 
of Willard Gibbs to explain the variations of specific heat of 
such bodies as nitric oxide and acetic acid. The results confirm 
the idea that such variations are due to the gradual dissociation 
of polymeric forms.—G. Lippmann, an “absolute spherical 
electrometer. Two hollow metal hemispheres, one fixed, the 
other held by a trifilar suspension, when similarly electrified, 
repel one another, with a force actually proportional to the 
square of the potential. The displacements are read optically. 
—MM. Bichat and Blondlot, on an absolute electrometer with 
continuous indication, This is an apparatus of three concentric 
cylinders, the innermost of which is suspended from a balance. 
The theory of it is already known.—P. Janet, on the formula of 
Van der Waals, and its application to capillary phenomena.— 
F. and W. Kohlrausch, the electro-chemical equivalent of silver 
(abstracted from Weéedemann’s Annalen). 
SOCIETIES AND ACADEMIES 
PARIS 
Academy of Sciences, August 23.—M. Fizeau in the 
chair.— Elliptical elements of Brooks’s Comet III. 1886, by Mr. 
J. R. Hind. The elliptical orbit, deduced from the observations 
made at Nice on May 25 and July 1, and at Algiers on June 3, 
is as under :— 
T = 1886 June 6°57145 Greenwich Mean Time 
229 45 58°0 
wv .. 
QB... «- 53 3 .25°7 ¢ Mean Equinox 1886:0 
fee eee > ee 5Omr so: 
Cl ice ee) SY 7 SO 
log a 05329478 
(Pos 563” 0992 
Period 6*°301 
—On the measurement of very strong pressures and on the 
compressibility of fluids, by M. E. H. Amagat. For the mea- 
surement of very high pressures the author has adopted the 
principle of the manometer with differential pistons. In order 
to obtain accurate results, the condition had to be realised of 
maintaining the pistons in complete action while keeping them 
perfectly air-tight. The reading of the volumes of compressed 
fluid was effected by the process already indicated by Prof. Tait, 
of Edinburgh. Water and ether have been studied at zero and 
at the two respective temperatures of 20°and 4o° C. Respecting 
the variation with pressure, it is shown that the coefficient 
diminishes gradually with the increase of pressure, and this 
takes place throughout the whole scale of pressures, contrary to 
the opinion of some physicists. At 3000 atmospheres the 
volume of water was reduced one-tenth, and its coefficient of 
compressibility one-half. This coefficient between 2590 and 
2981 atm. was 0'0000238, and that of ether between 1623 and 
2002 atm. 07000045. The study of ether will be continued 
and pushed to 3000 atm., and in a future communication will 
be given the coefficients of compressibility and of dilatation for 
several other fluids up to 3000atm. A number of gases will 
then be examined with the same apparatus and within the same 
limits of pressure.—On the purple of the solar spectrum, by M. 
Camille Koechlin. The solar spectrum yields only two simple 
colours, blue and yellow. The third is blended with yellow 
and blue to constitute the reds on the one hand, the violet, 
on the other, purple being red deprived of yellow or violet 
deprived of blue, or simply the spectrum without yellow or blue. 
If on the red of one be projected the blue of another spectrums 
or on the violet of the first the yellow of the second, the result 
is purple. The red or the violet may again be restored 
by applying to the purple the yellow or blue of a third spectrum. 
And if these applications be made with reversed prisms, so that 
the complementary colours reciprocally cover each other, the 
spectrum will present at both extremities a purple region with 
yellowish-white interval. Purple, being a simple colour, will 
thus never be obtained by mixture, but only by extracting the 
yellow from a red or the blue from a violet. The solar spectrum 
contains the elements of all shades, either by mixtures or by 
diluting with white or extinction with black. In the latter case 
the colours containing blue preserve their tint, while those on 
the opposite side of the yellow become changed in character. 
Thus green, blue, and violet yield the so-called deep greens, 
blues, and violets, while the yellow, orange, red, and purple 
cannot be intensified, but pass over to olive, brown, garnet, or 
amaranth. —On the branchial apparatus and muscular and 
nervous systems of Amaracium torquatum, by M. Charles 
Maurice. In this Compound Ascidian, which abounds at Ville- 
franche-sur-Mer, the branchial apparatus presents thirteen rows 
of stigmata, and is otherwise characterised by three fundamental 
peculiarities connected with the transverse sinus.—On a larva of 
Lampyris noctiluca surviving the loss of its head, by M. Frangois. 
This specimen, which had lost the whole of the cephalic region, 
was found in a perfectly healthy and normal condition, and al- 
though destitute of any buccal orifice, it showed on dissection 
an abundance of adipose tissue. The cesophagus, however, 
had changed its position, and contained no trace of alimentary 
matter.—On the cyclone that swept over the Gulf of Aden in 
June 1885, by Admiral Cloué. As supplementary to the 
previous statement on this subject, the writer has collected 
further details from the captains of some English and Dutch 
vessels overtaken by the storm, and from Obock regarding the 
caravan which was ez route for Shoa when the whirlpool swept 
by.—Kemarks on Dr. W. C. Gore’s memoir on the ‘‘ Projectiles 
ot the Future,” presented to the Academy, by M. Larrey. In 
the interests of humanity, which are above those of war, it is 
argued that the use of explosives should be more and more re- 
stricted, and replaced by projectiles calculated rather to wound 
than to kill the combatants. With this object it is proposed to 
substitute for the explosive bullets now in use the so-called 
“© Lorenz” projectiles, which are described as ‘‘the missiles of 
the future.” 
BOOKS AND PAMPHLETS RECEIVED 
“Report of the Entomologist C. V. Riley for 1885” (Washington).— 
“Bulletin of the U.S. National Museum, No. 30,” by J. B. Marcou 
(Washington).—‘** Géologie de l’Ancienne Colombie, Bolivarienne Vénézuela, 
Nouvelle-Grenade et Ecuador,” by H. Karsten (Friedlander, Berlin),— 
“Jahrbuch der Meteorologischen Beobachtungen der Wetterwarte der 
Magdeburgischen Zeitung.” Jahrgang ill, 1884, by Dr. R. Assmann 
(Magdeburg).—** Reports on Insects injurious to Hop Plants, &c.,” No. 3 
“*TInsects injurious to Fruit Crops,’’ by C. Whitehead (Eyre and Spottis- 
woode).—‘* Lectures to Kindergartners,” by E. P. Peabody (Heath and 
Co., Boston). —‘‘ Transactions and Proceedings of the New Zealand Insti- 
tute, 1885,”’ vol. xvili., by J. Hector (Wellington).—‘“‘ Philip's Plani- 
sphere, showing the Principal Stars visible for every Hour in the Year’ 
(Philip).—‘* Catalogue of the Blastoidea in the Geological Department of 
the British Museum (Natural History),” by R. Etheridge, Jun., and P. H. 
Carpenter (London).—‘‘ Choice and Chance,’’ 4th edition, by W. A. Whit- 
worth (Bell and Son). 
CONTENTS PAGE 
Chemical Epes By Prof. Henry E. Armstrong, 
eR Sse e) erie: o | 'o) lel Leh lelgcchct nails) Momrefilte itelammmneE Oy 
Our Book Shelf :— 
Hartmann’s ‘‘ Madagaskar, und die Inseln Seychellen, 
Aldabra, Komoren, und Maskarenen” .... . 406 
Letters to the Editor :— 
Physiological Selection and the Ongin of Species.— 
Prof. Francis Darwin, F.R.S.; Dr. George J. 
Romanes, F.R.S. .. 407 
Earth- Currents and Aurora. —Prof. “Ww. F. Barrett 408 
Chlamydomyxa in the ebendine: —Prof. E. Ray 
Lankester PIR Ss0 seme : «jee OS 
The British Association :— 
Inaugural Address by Sir J, William Dawson, 
C.M.G., M.A., LL.D., F.R.S., F.G.S., Prin- 
cipal and Vice-Chancellor of McGill Uatversio 
Montreal, Canada, President . . Sik uho) £18) 
Section A—Mathematical and Physical " Science— 
Opening Address by Prof. G. H. Darwin, M.A., 
LL.D., F.R.S., F.R.A.S., President of the 
Section’ oe 420 
Section B—Chemical "Science—Opening Address by 
William Crookes, F.R.S., V.P.C.S., President 
of the Section. ({lustrated) . oe 28 
Notes - = : f. 0. e | ae 
Our Astronomical Column ; — 
INotesion Variable Stars) <) jf) i) vet ie) =tso oto) 
Winnecke’s Comet . . aitel Tal: Ye, onan SameS eS 
The Observatory of Yale College . OS - AGS 
Astronomical Phenomena for the Week 1886 
SENET OTT yc iat MRCIRMRD TUR Cr 7) aan 
Scientific Serials 3 Sys) ies 
Societies and Academies Minas tae.) eae 436 
Books and Pamphlets Received ee ae eS) ot 436 
acne’ 
