462 
which, Loch Goil, was only half a degree warmer than in 
April. The range of surface temperature in June was from 
45° to 53°, and of bottom temperature from 42° to 47°°3, 
according to locality. Constant temperature to the bot- 
tom commenced at a much lower depth than in April. 
In the upper basin of Loch Long, which was discussed with more 
fulness, the surface-temperature was 48°°4, at 10 fathoms it was 
°-9 and from 55 fathoms to the bottom at 70 fathoms it was 
my) 
44°. But between 10 fathoms and 55 fathoms the water was 
colder than at either of these points, reaching its lowest tempera- 
ture of 42°°8 at 20 fathoms. It thus appeared that a lenticular 
mass of water floated between the warmer strata, the opinion as 
to the cause of which was meantime reserved until further light 
can be thrown on the phenomenon. In the Clyde district, 
Dr. Mill said, physical configuration is the determining cause 
of differences of temperature, and it appears that as the season 
advances, warmth descends from the surface everywhere by 
conduction, and travels inward from the sea by conduction and 
convection. The study of water climate, he said, was likely to 
lead to important results, but it must he carried on by a large 
number of observers, who would note the temperature of rivers 
and of falling rain, before any degree of completeness could be 
obtained. The paper was illustrated by a series of admirable 
charts. 
SCIENTIFIC SERIALS 
THE Fourna! of the Franklin Institute, August.—Capt. O. E. 
Michaelis, the applications of electricity to the development of 
marksmanship. ‘This is the conclusion of an interesting paper 
on chronoscopic and chronographic methods, illustrated by cuts 
of recent instruments.—W. Lewis, experiments on transmission 
of power by gearing (conclusion of the discussion).—F, Lynn- 
wood Garrison, the microscopic structure of car-wheel iron.— 
G. Richmond, the refrigeration-machine as a heater.—C. Hoele, 
a method of designing screw propellers.—F. E. Ives, correct 
colour-tone photography with ordinary gelatine bromide plates. 
A proposal to reduce the sensitiveness of the bromide films to 
the blue and green rays, by introducing into a plate-glass tank 
mixtures of aniline colour solutions, chiefly yellow and red, in 
certain proportions, thereby equalising the sensitiveness through- 
out the range of the visible spectram.—Joshua Pusey, sugges- 
tions towards a simplified system of weather signals, termed the 
index weather-signal system.—P. E. Chase, Herschel and Jevon 
on density of the ether. 
Annalen der Physik und Chemie, vol. xxvili, No. 8, August 
1886.—Prof. G. Quincke, electrical researches, No. xii., on the 
properties of dielectric fluids under strong electric forces. The 
dielectric constant of a number of liquids is examined by two 
methods, by attraction between two plane parallel plates im- 
mersed in the liquid, and by discharge of their charges through 
a galvanometer. High potentials were obtained by a Holtz 
machine, and measured by a long-range electrometer up to 
30,000 volts. The results show that with high electric forces 
the dielectric constant is less than with lower electric forces ; in 
other words, there exists an apparent tendency to saturation in 
inductive capacity. Measurements of the dielectric constant are 
always from 10 to 50 per cent. higher when made by the 
balance-method than those made by the condenser discharge 
method. In different dielectric fluids the spark-distance for the 
same difference of potentials is different, and always much 
shorter than in air. The potential requisite to produce a spark 
within a dielectric liquid increases with the spark-length, but at 
a slower rate. The strength of a steady electric current ina 
dielectric fluid increases more rapidly than the electromotive 
force which produces it ; an exception, apparently, to Ohm’s 
law.—L. Sohncke, electrification of ice by water-friction. Ex- 
perimental proof that water becomes negatively electrified and 
ice positively electrified by mutual friction. The author thinks 
thereby to explain the origin of thunderstorms by friction of 
cumulus and cirrus clouds.—E. Edlund, researches on the 
electromotive force of the electric spark. He finds the counter- 
electromotive force of the electric spark to be divisible into two 
parts, one at each pole, that at the positive pole decreasing, and 
that at the negative pole steadily increasing, as the air-pressure 
is diminished. He regards this as explaining the anomalies of 
unequal heating of the electrodes. —W. Donle, contributions to 
knowledge of the thermo-electric properties of electrolytes. 
According to these experiments the thermo-electromotive force 
NATURE 
———————————— nnn 
between two electrolytes, such as solution of sulphate of coppel 
and sulphuric acid is approximately proportional to. the ditfer- 
ences of temperature of the points of contact; the proportion- 
ality varying in some way with the concentration of the solu- 
tions. The electromotive force is usually less with more con 
centrated solutions. Through the heated junction of a chloride 
and a sulphate the current flows from chloride to sulphate. — 
Auerbach, on the electric conductivity of metal powders. 
Precipitated silver was used. The author finds an enormous 
reduction when the density is increased by mechanical force. 
R. Kriiger, on a new method of determining the vertical in- 
tensity of a magnetic field. This method consists in sending an 
electric current radially through a horizontal copper disk sus- 
pended by a thin wire, and observing the rotation of the disk,- 
R. Maurer, on the ratio of the sectional contraction to the 
longitudinal elongation produced in rods of glue-jelly. The 
rods were made of gelatine and water, and of gelatine and 
glycerine. One of the methods was an electrical one, consist- 
ing in observing the change of electrical resistance on stretching. 
These jelly rods exhibit the phenomena of residual strains very 
markedly.—M. Hamburger, researches on the duration of the 
impact of cylinders and spheres.—Dr. K. Noack, on the fluidity 
of absolute and diluted acetic acids. Curious minima of fluidity 
are observed by the author, varying with concentration and wit! 
temperature.—W. Miiller-Erzbach, the law of decrease of 
absorbing power with increasing distance. 
SOCIETIES AND ACADEMIES 
EDINBURGH ‘ 
Royal Society, July 19.—Mr. Robert Gray, Vice-President 
in the chair.—The Right Hon. Lord Rayleigh communicated 
paper on the colours of thin plates. He has laid down on 
Maxwell's triangle of colours a curve representing the variation 
of the colours of thin plates as the thickness of the plates in- 
creases.—Prof. Dr. Fr. Meyer communicated a paper on alge- 
braic knots.—Prof. Tait described Amagat’s ‘ manométre a 
pistons libres.” —Prof. C. G. Knott communicated a paper on 
the electrical properties of hydrogenised palladium. This paper 
contains the results of experiments on the resistance and thermo 
electric properties of hydrogenium or hydrogenised palladium. 
Up to a temperature of about 200° C. no special peculiarity is 
noticeable ; but at that temperature, or a little higher, hydrogen 
begins to escape from the wire, and this causes the particular 
specimen of hydrogenium to recover partially, if not wholly, its 
pure palladium characteristics. It is known that the resistance 
of a palladium wire charged with hydrogen at ordinary atmo 
spheric temperatures increases at_a rate almost strictly propo: 
tional to the amount of charge. 
at all temperatures up to 150° C., and in such a way that the 
total increase of resistance of a given palladium wire for a given 
rise of temperature is nearly the same at all charges ; or the 
temperature-coefficient for any particular specimen of hydrogen- 
ised wire is practically inversely proportional to the resistance 
as compared with the resistance of the wire in its pure uncharged 
state. Just before the hydrogen begins to escape, the resistance 
begins to increase somewhat more rapidly than at lower te 
peratures ; and this peculiarity is more marked in the specimens: 
of higher charge. When once the hydrogen begins to escapes 
the resistance begins to fall off rapidly as the temperature rises. 
to 300° C. At this temperature the wire cannot be distinguished: 
as the wire is cooled down again. 
below 150° C., the current is from pure palladium to hydro 
genium through the hot junction, is probably proportional to the 
difference of temperature in each case, and is greater for the 
greater charge. Thermo-electrically, fully saturated hydroge 
nium lies between iron and copper at ordinary atmospheric tem- 
peratures. On the thermo-electric diagram the hydrogeniums of 
different charge are represented (up to a temperature of 150° C.) 
by a series of straight lines perallel to palladium, whose thermo 
electric powers at o° C. range roughly from — 600 (pure palladium) 
to + 1400 (saturated hydrogenium) expressed in C.G,S. units 
(Compare Everett’s ‘‘ Units and Physical Constants,” p. 151.) 
