SCIENTiriC SUMMARY. 
135 
acquainted with the law of the dilatation of these inter-molecular spaces, we 
could determine the relative sizes of the molecules of hydrogen and nitrogen. 
When the internal pressure is at the highest mark, the mixture is analyzed. 
M. Deville has given the results of several analyses, and from them we select 
the following one : — 
External Pressiire 
Internal Pressure 
Composition of Gases 
Pressure of 
of Hydrogen. 
of Mixture. 
in Iron Tube. 
each Element. 
760mm. 
1,451mm. 
Hydrogen 57*4 
833mm. 
Carbonic oxide 05*2 
75 
Nitrogen 37*4 
543 
110-0 
145 
Such results the author of the paper confesses to be quite in opposition to 
all that is known relative to the laws of diflPusion of gases. They may be ex- 
plained by one of the two following suppositions : — 
1. In the interior of the tube a mixture of nitrogen and hydrogen acts in 
the same manner as homogeneous matter, drawing toward it the pure hydrogen 
from the exterior, as though part of the physical properties of the hydrogen 
were destroyed by admixture with nitrogen. This explanation it is hard to 
admit in the present state of science. 
2. In the interior the gases are at rest, but externally they are in motion. 
If the results may be attributed to this, then it would be possible to draw 
some very important conclusions in regard to the mechanical theory of heat, 
and to form new views concerning the constitution of gases, and Graham’s 
recent laws ; but before taking these steps, the author proposes to re-investi- 
gate the whole phenomena. — Vide Comptes Rendus, July 15. 
The Movements of Chemical Matter when in Films upon the Surface of 
Water. — That indefatigable physicist, Mr. Charles Tomlinson, has been 
making a new series of investigations into the movements of chemical matter 
when in films upon the surface of water. Eugenic acid is the compound 
which has most recently been the subject of his inquiries. He finds that 
when a drop of this liquid is placed on the surface of two fluid ounces of dis- 
tilled water in a glass capsule two and a half inches in diameter, it forms 
what is termed a cohesion figure, consisting of a flattened disk of about -rirflis 
or -i^ths of an inch in diameter, which sails about on the water with a 
vibrating motion of the edge, not nearly so vigorous as the disk of creosote under 
similar circumstances. The eugenic acid disk often splits up into two or 
three smaller ones, which revolve round each other, and as they become smaller 
move more rapidly, and at length disappear in wild gyrations. The manner 
in which the disk is disposed of by solution, is by throwing off a number of 
films in rapid succession, Vhich are taken up by the water as fast as they are 
formed. In this way, a repellant action exists all round the disk, which action 
is at first tolerably equal in all directions, but by exposure to the air certain 
points of the edge of the disk become resinified and cease to give off films. 
The latter phenomenon then determines a very remarkable set of currents, 
which may be easily demonstrated by the employment of lycopodium. — Vide 
Chemical News, August 6. 
How to Increase the Constancy of DanielVs Battery. — This is effected accord- 
ing to Secchi’s plan, by the use of fine sand or sulphur in the porous 
