104 
rorULAE SCIENCE EE VIEW. 
Origin of the Heat developed, in the Cells of a Battery. — According to 
!M. Favre, the heat which is not found in the galvanic circuit, hut confined 
within the cell, can only be traced to the intervention of the following cir- 
cumstances, alone or united : 1st, the condensation of hydrogen on the pla- 
tinum (of a Smee’s couple), wdiich becomes an obstacle to the transmission 
of the current ; 2nd, the local action due to the passage of hydrogen from 
the nascent to the ordinary state ; 3rd, the action, also local, due to the con- 
version into sulphate of the zinc deposited on the platinum of the couples by 
the electrolysis of the sulphate of zinc constantly increasing in the liquid 
in the cells. — Comptes-llendus, Nov. 23. 
The Illuminating Potocr of Flame. — M. Deville cannot agree with 
Dr. Frankland in considering the degree of luminosity of a flame to be 
dependent upon the density of the gases forming it. The illuminating 
power of a flame entirely gaseous is a specific property connected with the 
production of the spectral lines furnished by the matters it contains j and is 
as inexplicable as the specific properties of the bodies themselves, such as 
density, colour, &c. For a flame to be luminous it is only necessary for it 
to be white, that is, for its spectrum to be extended. When the tempe- 
rature is raised all metallic spectra acquire new lines, take all the difierent 
colours which together form white light, and consequently acquire a greater 
illuminating power. — Comptes-Bendus, Nov. 30. 
Why Soap-Bubbles can be blown, and not Water-Bubbles. — Viscosity, as 
ordinarily understood, is quite insufficient by itself to explain the bubble- 
forming capability of certain liquids. According to M. Plateau (Comptes- 
Jiendus), “the superficial layer of liquids has a viscosity peculiar to it, and 
independent of the viscosity of the interior of the mass; in certain liquids 
this superficial viscosity is stronger than the interior viscosity, and often 
very much so ; in other liquids it is, on the contrary, weaker than the inte- 
rior viscosity, and often also very much so and he is led to conclude from 
his experiments, that for a liquid to be capable of being spread out in sheets 
at once large and persistent, and consequently for it to permit of being 
blown into bubbles, in the first place its superficial viscosity must be great ; 
but besides this, its tension must be relatively feeble ; in other words, the 
ratio of its superficial viscosity to its tension must be sufficiently high. 
Researches on Calorific Spectra. — Further experiments by M. Desains serve 
to establish the statement he had previously made to the French Academy, 
that if in perfectly pure spectra pencils are isolated, composed of rays whose 
deviations through the same prism are almost identical with each other, 
they will be found to be very unequally transmissible through the same 
absorbent medium when they proceed from difierent sources (Comides- 
Rendus^ Nov. 30). F Instil ut remarks that this discovery of M. Desains 
gives the coup de grace to the error firmly rooted in the minds of physicists, 
that a colour or a radiation is perfectly determined either by its wave-length 
or by the duration of its vibration. 
Similitude of Jlydraulic Trajectories. — According to M. Brettes, hydraulic 
trajectories appear to be similar when the initial velocities of the water 
coming out of similar orifices make the same angle with the horizon, and 
are proportional to the square roots of the diameters of these orifices if they 
