Daily globe. [volume] (St. Paul, Minn.) 1878-1884, 1883-08-22

vanometer," by Prof. B. +. Thomas.
The method consists in passing definite
parts of unit current through the gal
vanometer, noting the reflections and
plating the curve. A battery of any sort
is Joined in circuit with a sensitive
galvanoscope. The paper was
illustrated with a descriptive black
board drawing, without a reproduction of
which it is practically impossible to give
the reader an INELIGIBLE report, or idea
of the workings of the proposed method.
sELENIUM CELL.
G. E. Fritts being absent, Prof. Men
denhall presented an abstract of the paper
On new form of selenium cell and some
remarkable electrical discoveries made by
its use.
SOLIDS AND LIQUIDS.
Prof. H. T. Eddy, of the University of
Cincinnati, presented lengthy paper on
"Liquefaction, Vaporization and the
Kinetic theory of Solids and Liquids" of
which the following is an abstract:
In solid, in which the molecules are
evidently held at nearly fixed mean dis
tances by cohesive and elastic forces, there
are two kinds of partially constrained
freedom of motion possible for each mole
Guile as a whole; first a motion of its
center in a small orbit of more or less ir-
regular shape about mean position; and
second, more or less irregular pendular
motion of oscillation about a mean direc-
tional position. Both of these motions
can be properly treated as vibratory mo-
tlons, and the laws of force under which
the motions occur, though somewhat
unlike, have general resemblance.
When a solid is liquefed, it is evident
that the molecules slide on each other with
facility, which is equivalent to supposing
that the molecules of the body have be-
come perfectly free as to directional posi-
ton; and this may be explained by sup
posing that the pendular oscillation has
been changed into rotation. In ordinary
evaporation into the atmosphere, without
ebullition, only those molecules
escape from the surface
whose kinetic energy is such
as to enable them to overcome cohesion,
and only so many will escape as will ena-
BILE the vapor to fulfill approximately the
law of Gay Lussac. There are three kinds
of vaporization possible, evaporation
ebullitisn and classification. There appears
however, to be only one kind of liquifca-
ton (melting) which is most nearly anaIo
gous to Classification, end without further
reasoning it will appear that for these
substances,whose melting power is lowered
by pressure, there must be critical tenn
perature of melting, above which the body
will be liquid, whatever be the pressure;
Z. e., no pressure can lower the melting
P ONT beyond certain amount dependent
upon the constitution of the body.
1t appears from experiment that the
specific heat of mercury is nearly the same
In its solid and liquid states as 1t should be
in case its molecules are monatomic in
both states. 1t would be of great interest
to know whether the specific heat of mer-
curry gas has the same value. It is notice
able that the latent heat of lquifaction of
mercury is extremely small, which would
lead to the hypothesis that the atoms of
mercury are very nearly round and smooth
and that the rotary energy of a molecule
of mercury is but very small fraction of
its total kinetic energy.
These conclusions to be drawn from the
specific heats of elementary substances
whose molecules consist of but two like
atoms are in general confrmatory of the
theory proposed in this paper, for the
amount of rotary energy for such substan-
ces should be less fraction of the total
energy than in bodies consisting of lar
ger number of atoms, and the per cent.
of dissertation should also be less. Now,
in fact, for such bodies the specific heat
in the liquid state does not, in general,
greatly exceed that in the solid.
KINETIo THEORY.
A paper on the Kinetic theory of mel
ting and boiling, was presented, also by
Prof. Eddy. The object of the paper, he
| said, was to consider the probable phys1-
cal state of solid bodies, especially as to
the amount of energy, the different degrees
| of freedom possible in such bodies and to
| show that the same hypothesis of equal
ultimate atoms, would cause solids, which
are in equilibrium by radiation, to be also
in thermal equilibrium when brought into
contact,i. when the equilibrium depends
upon the collisions of the molecules.
Thermal equilibrium which has been es-
tablished by collisions of gaseous and
solid molecules, will continue to exist
when its continuance depends upon radi-
alton between equal and similar ultimate
atoms, which are set in vibration by col
lisions with molecules; or to state it diff
ferently, it remains to be shown that the
ultimate atoms of gas and solid in
contact, each give the same mean vibratory
energy, with respect to each other. This
appears to be direct consequence
of the principles of constrained motion.
1t is very necessary that the impacts of
pair of solid molecules with each other
should be such as to mutually impart and
receive the same mean amounts of energy
as those of a gas and solid, to cause it to
be a matter of indifference, whether
given solid molecule struck by another
solid molecule or by a gaseous molecule
and when so struck each ultimate atom
will receive its proper proportion of
energy, whether it form part of solid or
| gaseous molecule.
The next paper was by Prof. Gustavus
Hinricks, of Iowa, on the tracings of self
registering disbursements and the value of
the q. S. indications for Iowa in June and
July, 1888.
The speaker attacked the system of the
United States signal service. He cited in
stances, especially in June, in the state of
Iowa, where there were twelve stations
we'll distributed over the entire area,
which reported every five days by card, to
| show that it was matter
| of conjecture and not a scientific