, 
, 
Fan. 18, 1883] 
such as (a) Alterations in the relative levels of different parts of a 
floor of a valley, connected with movements of parts of a moun- 
tain-system on a large scale. The effects of (1) lines of flexure 
crossing older lines of valley-erosion; (2) of lateral thrusts 
closing in a valley (partly), were here considered. (4) Upthrust 
of the more yielding strata (as in the ‘‘ creeps” of coal-mines) by 
resolution of forces due to pressure of the mountain-masses at the 
side of a valley. (c) The dead weight of the huge g'aciers which 
filled the Alpine valleys, and crushed in the floor, in places where 
extensive underground erosion had gone on in preglacial times. 
(d) The partial damming up of valleys, (1) by diluvial detritus, 
(2) by moraines, (3) by Bergstiirze (rece itly inves‘igated by 
Prof. Heim of Ziirich. (e) Halts. (/f) Chemical solution, by 
Alpine waters derived from the melting of the snow, which has 
undergone long exposure to tlle atmosphere. It was shown that 
the very situation of the great majority of the lakes of the 
Northern Alps is distinctly favourable to the operation of one or 
more of these agencies. The Konigsee was mentioned as a 
special instance of szdsidence ; the Achensee of a lake lying ina 
faulted line of dislocation; Lake Alleghe and Lake Derborence 
as lakes formed by Bergstiirze during the last century; the pre- 
historic delta of the Arve as the most conspicuou: instance in 
the Alps of the partial damming-up of a valley by diluvial 
detritus ; the gwondam Lake of Reutte as an instance connected 
with violent inversion of strata; and the ancient lakes of the 
Grédner and Oetz Thals as instances of the action of moraines. 
The common fact of observation that lakes are more numerous 
in glaciated than in non-glaciated countries, the author thought, 
was partly explained by some of the foregoing principles, partly 
by the better preservation of lake-ba-ins in glaciated countries 
from silting up and from becoming thus obliterated, while in 
some glaciated regions lakes are wanting. 
_ Victoria (Philosophical) Institute, January 15.—Prof. 
Stokes, F.R.S., Lucasian Professor of Mathematics at Cam- 
bridge, read a paper on the Absence of Real Opposition 
between Science and Religion. 
t EDINBURGH 
Royal Society, December 18, 1882.—Mr. Robert Gray, 
vice-president, in the chair.—Prof. Tait read a paper on the 
laws of motion, in which an attempt was made to express the 
fundamental principles of dynamics without introducing the idea 
of ‘‘force.” The conservation of energy forms of course the 
basis. The region of space, in which a given particle is, is 
mapped out by its equipotential surfaces. Newton’s First Law 
is expressed, then, by sayinz that the potential of the space is 
the same from point to point, so that the kinetic energy of a 
moving particle suffers no change. If the potential varies, then 
the kinetic energy must vary. As a simple case, consider two 
regions separated by a plane, the potential function being con- 
stant throughout each region. Then the velocity of a particle 
approaching the plane may (since motion is purely relative) be 
referred to a point moving parallel to the plane, so as to make 
the velocity of the particle wholly perpendicular to the plane. 
It thus appears that the component of the velocity at right 
angles to the plane only is altered, so that if the direction of 
motion is originally inclined to the plane, the direction as well 
as the speed is altered. This, in fact, is the well known problem 
of refraction according to the corpuscular theory of light; and 
the principle of least action thus appears under the form of the 
conservation of velocity at right angles to the direction of 
greatest potential slope. In expressing Newton’s Third Law, 
Prof, Tait extended the second interpretation as given in the 
now well known Scholium to include vector as well as scalar 
quantities.—Mr, George Seton, in a paper on illegitimacy 
in Scotland, gave a careful analysis of the returns for the 
last decade, which showed a decrease of ‘9 per cent. as com- 
pared with the returns of the previous decade. The counties in 
which the -percentage was under the average for the whole 
country all lay to the west of a line drawn from the north coast 
to Loch Ryan, down the eastern boundaries of Sutherland, 
Inverness, Perth, Argyle, Renfrew, and Ayr. That this differ- 
ence could not be referred as altogether due to difference of 
race was proved by the fact that amongst the pure Scandinavian 
population of Orkney and Shetland the rate was much below 
the average. The results pointed to a low moral tone in the 
agricultural districts of Elgin, Banff, Aberdeen, Roxburgh, aud 
Galloway.—Prof. Tait communicated an account of Prof. J. E. 
MacGregor’s experiments on the absorption of low radiant heat 
by some gaseous and vaporous bodies. The apparatus was 
NATURE 
283 
a gigantic form of that which has already been described in 
these columns (see NATURE, vol. xxvi. p. 639). Air saturated 
with water vapour at 12° C. behaved almost exactly like air 
mixed with ‘06 per cent. by volume of olefiant gas.—Prof. Tait, 
in a note on the compressibility of water, stated that water 
seemed to be less compressible at higher than at lower pressures, 
and more compressible (as compared with steel or glass) at lower 
than at higher temperatures, ‘This latter result was obtained by 
comparison of his own laboratory experiments with the experi- 
ments carried out by Mr. Murray and Prof. Chrystal in their 
deep-sea sounding expedition last summer on the north-west coast 
of Scotland. Both series of experiments were made with Prof 
Tait’s steel and glass gauges.—Prof, Crum Brown communicated 
a note by Mr. A. P. Laurie on an application of Mendeljeff’s 
law to the heats of combination of the elements with the halo- 
gens. Laying off as abscissee numbers representing the heats of 
combination of different salts of a given halogen, and measuring 
as ordinates the corresponding atomic weights of the other ele- 
ment in the compound, Mr. Laurie obtains a succession of 
points which show a remarkable periodic arrangement. The 
curves so drawn for the different halogens are strikingly similar. 
PARIS 
Academy of Sciences, January 8.—M. Blanchard in the 
chair.—The following papers were read :—Observations on the 
last communication of Dr. Siemens concerning solar energy, by 
M. Faye.—On the ice-plant (A/esembrianthemum crystallinum), 
by M. Mangon. This plant (which is covered with transparent 
vesicles filled with liquid, like frozen dew-drops) is formed of a 
weak solution of alkaline salt, kept in the solid state by a vege- 
table tissue, whose weight reaches less than two per cent. of the 
whole mass. The ashes, formed of salts of soda and potash, 
constitute nearly half (43 per cent.) the weight of the dried 
plant (recalling seaweed). M. Mangon notes the plant’s elective 
power, suggests that its cultivation, as a potash-plant, might be 
useful insome cases, and in any case, it might do gocd service 
in removal of alkaline salts in excess from ground on the 
Mediterranean coast.—Researches on hyponitrites ; second part ; 
calorimetric measurements, by MM. Berthelot and Ogier.—On 
the natural formation of bioxide of manganese, and on some 
reactions of peroxides, by M. Berthelot.—Experiments relating 
to disorders of motility caused by lesions of the apparatus of 
hearing, by M. Vulpian. He describes a series of disorderly 
movements produced in rabbits by pouring a few drops of 
Lydrate of chloral solution into one ear or both ears. The same 
experiment with dogs and guinea-pigs gave much less marked 
effects. —On complex units, by M. Kronecker.—Examination of 
the analogy between: electrochemical and hydrodynamical rings, 
and the curves AV=0; Best process of discussions in the experi- 
mental method, by M. Ledieu.—Experiments on the motion of 
current waves in various passages, contracted either in the in- 
terior or at the extremity of a canal debouching into a reservoir, 
by M. de Caligny.—Report on a memoir of M. de Salvert on 
conic umbilici.—On the precision of longitudes determined with 
use of the new chronometric method, by M. de Magaac. He 
shows by a list of chronometric longitudes obtained in the Feax 
Bart, ou the coast of Brazil and Montevideo, compared with the 
telegraphic longitudes’ deduced from observations by three 
American officers, that the difference is remarkably small.—A 
case of damage to a building from lightning was reported ; the 
effect was attributed to breaks in certain metallic parts (there was a 
good lightning-rod and there were trees near).—The periodicity 
of comets, by M. Zenger. He finds the origin of comets in- 
timately connected with the rotation of the sun. Dividing the 
intervals of times of perihelion by various whole numbers, he 
obtains a mean value of 12°56 days, which is exactly that of a 
demi-rotation of the sun. Thus, between successive formations 
of conets there must have elapsed an even or odd number of 
solar demi-rotations. He supposes enormous explosions driving 
far out the matter of protuberances ; large meteorites near the 
outer border of the corona may thereby be enabled to agglomerate 
coronal matter round them and form acomet. The general law 
of motions of planets applies equally to comets, but the duration 
of revolution of comets must be a multiple of that of a half- 
rotation of the sun.—Addition to a note on prime numbers, by 
Mr Lipschitz.—Influence of cooiing on the value of maximum 
pressures developed in closed vessels by explosive gases, by 
M. Vieille. —Remarks on the expression of electric magnitudes 
in the electrostatic and electromagnetic systems, and on the 
relations deduced from it, by MM. Mercadier and Vaschy.— 
