SICS AND NATURAL HISTORY OF GENEVA,

M JULY, 1862, TO JUNE, 1863.

BY PROFESSOR MARCET, PRESIDENT.

RANSLATED FOR THE SMITHSONIAN INSTITUTION.

has been the custom of my predecessors, to present an s of the society during the year just elapsed, it is- but acknowledge how greatly my task has been facilitated by ness with which the reports of our several meetings have ir secretary, M. Ed. Claparède. Among the topics claiming have been already communicated to the public, or are about e medium of scientific journals; as regards these, therefore, If to an indication of the titles, or a very summary analysis rived at. In the arrangement of subjects I cannot do better ion into two sections, that of the physical and that of the st proposed by M. de la Rive, and since observed by the presidents who have succeeded him. I shall follow, moref my immediate predecessor in touching very lightly on the ave taken place either on the occasion of original memoirs ety or of verbal reports on recent discoveries made in other these discussions have not often possessed a genuine interest, sential, if this valuable observance is to be retained by us, on of the labors of others, the verbal communications in mes led to enunciate ideas arising at the moment and perhaps atly considered, should receive no greater publicity than that the reading of the journal of our sittings.

PHYSICAL SCIENCES.

le colleague, Professor Gautier, has continued to keep the ed of the discoveries made in astronomy. His communicamerous and diversified; we must here limit ourselves to the t important. M. Gautier presented to the society, in the first the observations of M. d'Arrest, of Copenhagen, relative to o the variability in brightness of the nebula, as well as to doubtful, which would tend to indicate a proper movement odies; secondly, an account of a memoir of M. Lamon on the tions of magnetic declination, and the analysis of researches he flattening of Mars, which he estimates at ; thirdly, a ent observations of M. Donati on the comets, and on a memoir relative to stellar spectra: M. Gautier announced on this

39

sics establishing a natural bond between I called, we shall first direct our attention to owe to Professor Plantamour. Besides the r Geneva and Saint-Bernard, published, as al and natural sciences of the "Bibliotheque communicated to the society an interesting ade at Geneva, for thirty-five years, on the He has found that in winter the number of inds balance each other; the northeast pren, the southwest in summer. The general which proceeds from the fact that the mean nearly approximates to north than does the 3 to south. The above results are somewhat s be taken into account and if local are disThe former depend chiefly on the vicinity of erature in the twenty-four hours, giving rise vening, analogous to breezes of the land and our has been lately published in his extensive (See page 15, et sequent.)

to the Society during the year und
has communicated to us, at two co
aches on the phenomena which char
cricity in highly rarefied elastic f
M. de la Rive insists more parti
d to measure the intensity of the
g himself of a derived current ta
in the distilled water placed in
also describes a manometer which e
part of a millimetre, and, for prac
sion of the elastic fluid submitt
la Rive have been directed to atm
has studied, in the case of each of t
and form of the gaseous mass, as
mitting electricity. He has
the electric light assumes, in prop
and particularly the variable form
gether with the formation of a vi
as a negative electrode, and of
in length, which separates that p

society a memoir on the diurnal variations of
ir likewise published in the work just men-
eview and combated as insufficient the theories
, M. Plantamour concludes in favor of that
g to which the phenomenon of the diurnal
stinct influences, one resulting from the tem-
ther from a kind of electric attraction, whose
own, but owing probably to the action of the
preference for this theory over the preceding
hes the means of explaining the double diurnal
ae barometer, while the influence of the tem-
to produce but a single one. The author
, a comparative table of the diurnal variation
rometer for Geneva and Saint-Bernard.
hat relates to terrestrial physics and meteor-
ommunications, one from Professor de la Rive,
erved in the month of December, in which the
west was perfectly evident, and another from
ted to the Society an apparatus constructed
workshop of M. Schwerdt, an apparatus de-
ights by a determination of the temperature of
onstruction of this instrument, the chief object
perfect precision in thermometrical indications,
been wanting. He has succeeded, on the one
the thermometer with two envelopes of vapor
riations of temperature proceeding from with-
prevents the effect of an ebullition often too

He has satisfied himself, in
ts, that these appearances of
a mechanical effect produced by
had already been advanced by
in showing, by direct experimen
nsists in a considerable dilatation
de, followed by alternate contract
sitive electrode. First. He was

ter, the existence of the oscillat
the variations in its intensity, wh
degree of tension, and dimensi

. He has demonstrated experin
a suitably arranged, derived cur
as column, all traversed by the sa
in the intensity of these currents
parts possess a greater conducting

With hydrogen, the best cond
ained in the obscure part of the co
that the indications of the thermo
ed column conduct us to the sam
the temperatures of those differ
ly less warm than the luminous,
ctors. The author has obtained a
g the differences of temperature, a
the gaseous column traversed by the

la Rive completed his communi
ng to the Society the modifications
propagation of electricity, through b

ich has played the principal part in the communications ring the year under review. Our colleague, M. de la d to us, at two consecutive meetings, the results of his >mena which characterize and accompany the propagation rarefied elastic fluids. In the classification of his apinsists more particularly on the means which he has emintensity of the discharges or transmitted currents, by erived current taken by means of two small sounds of I water placed in the circuit of the principal current. nometer which enables him to appreciate to nearly the etre, and, for practiced eyes, even to the hundredth part, stic fluid submitted to experiment. The researches of en directed to atmospheric air, nitrogen, and hydrogen. case of each of these gases, the influence of the dimengaseous mass, as well as of the pressure, on its capacity ricity. He has described the successive appearances it assumes, in proportion as the pressure of the gas diminthe variable form and size of the stratifications of that e formation of a violet-colored photosphere around the ball electrode, and of a black space, from five to ten centich separates that photosphere from the stratified luminous tisfied himself, in the course of a great number of exe appearances of electric light in rarefied gases are effect produced by the transmission of electricity, an idea been advanced by M. Riess. M. de la Rive has sucy direct experiments, that the mechanical effect in quessiderable dilatation of the gaseous matter near the negative y alternate contractions and dilatations in the column up to e. First. He was easily able to verify, by means of the ence of the oscillatory movement in the gaseous column, n its intensity, which depends, as he has shown, on the nsion, and dimensions of the gaseous mass in question. monstrated experimentally that if, by means of small sounds ranged, derived currents are taken in different parts of the traversed by the same discharge, great differences will be 7 of these currents, differences which prove that the obgreater conducting capacity, and are consequently the most ogen, the best conductor of the gases, no derived current scure part of the column. Thirdly. M. de la Rive points ions of the thermometer placed in different parts of the duct us to the same results, by evincing great differences tures of those different parts; the more obscure parts being han the luminous, which proves that the former are better thor has obtained a great number of numerical results, inces of temperature, at different pressures of various portions in traversed by the discharges.

pleted his communication at a subsequent session, by exty the modifications produced in the phenomena relative to _ectricity, through highly rarefied mediums, by the action of

n of the current, the nature of the gas, and its
so remarked the very great difference which the
ng as the rarefied gas is dry or contains vapor
first case, the luminous discharge expands under
to a sheet which forms the surface of a sector, or
n the gas is much rarefied. In the case in
very
rarefied gas, the discharge, instead of expanding,
number of small partial jets at equal interspaces,
ated by a movement of rotation around its centre.
of the same kind, have led M. de la Rive to
permanent gases and vapors, in reference to the
heir molecular constitution. The author termi-
ir with some general considerations on this exten-
, for the present, conclusions too absolute would
stains from presenting them until he shall have
extending them to a greater number of gaseous

pale electricity by M. Wheats practicable to obtain despatches y The same physicist communicated phenomenon observed by M. A the summit of the Oldenhorn. Of the persons who accompanied hir of the telegraph. In a few mom Fratessor de la Rive, on his return, red to the Society several new sei attention, in particular, to an inve at had arrived, simultaneously wi the earth cannot be liquid in its i Em that it is not necessary to rec nally into the sun, in order to e re of that body. It suffices to a undetermined cause, is now gr ding to M. Helmholtz, the cale the rapidity of refrigeration ed to take account of an imp es in volume as it grows coo 7ew heat.

de la Rive presented to the Soci Kve, a memoir on the number of in

of linear currents. This men

to analysis.

Pssor Marcet has continued to in

more than is usual in an analysis of the memoir stification, not only in the importance of the subhat the results which he obtained have been hereents. The entire memoir is about to appear in Memoirs of the Society, now in the press.* owe to M. de la Rive the model of a new system odification which he has introduced into the battially calculated to render its management more instrument, which is extremely manageable, and f alumina, possesses the advantage of requiring endering superfluous the removal of the nitric or the service of several days and many experi ngle pair of this battery, M. de la Rive has been experiments of the electro-dynamics of Ampérequire five or six pairs of Grove or of Bunsen. unications by Professor Wartmann relative to arly to the limit of pressure which permits a us medium, as well as to the influence which the edium exercises on the passage of a current, the e attention of the society by an account of some ssed in the last reunion of the British Association s present. Among the communications made on cites more particularly the observations of M. ure of the sun. To avoid the inconvenience of a ustead of introducing the solar rays directly into

and

tural radiation; among others,
the surface of the ground, and of
it, which he has remarked duri
dtowards the north, not only at

hours of the day. The auth
the surface to the concurrence of
especially to the extreme dryness
as Tyndall has proved, peculiar

I. Mareet has taken advantage of

him to repeat at Queensland, experiments on nocturnal radiation rate climates. It would seem t Domenon of the increase of temper Ascend some feet above the surfa Lticated in our temperate climate

= glass a lens which is plane on the side next the zone either at the rising or sett

site side, so as to disperse the luminous rays quantity of light reflected by the plane surface. le to ascertain that towards the hour of noonday

resting memoir is given in this report.-See page

ree scarcely sensible, hardly ef ive has recently made some obse which would appear to lead to a

* See Archives des Sciences Ph