The Sun.
London, England, 1867-08-26 00:00:00

SCIENTIFIC JOTTINGS.

Certain bodies are attracted by magnets, others
repelled; the former are called magnetic, the others
diagmanatic. At his lectures at the Conservatoire
des Arts et Metiers, M. Becquerel shows this by
hanging the body to be experimented upon to one
of the scales of a balance between the poles of a
strong electro-magnet ; whenever the current breaks
the equilibrium, the body is either attracted or re-
pelled. But it is not possible to do so with a gas.
M. Chautard, professor of the Faculty of Sciences
at Nancy, has, however, imagined a method by
which he meets the difficulty. He encloses, by
a clever manipulation, the gas he wants to ex-
periment upon in a bubble of glycerine soap.
Thus, a bubble filled with oxygen is suspended
over an electro magnet, and strongly illuminated by
a Drummond light. Then, every time the current
passes, there is an unmistakable oscillation in the
bubble. M. Chaulard also shows experimentally
the diamagnetism of the vapour of magnesium. He
burns the metal under the poles of an electro mag-
net; the white column of smoke resulting there-
from is visibly split into two branches as soon as the
current passes. Dr. Vellari of Florence has found
by experiment : 1, that wood has a co-efficient of
dilatation increasing with the temperature ; 2, that
it has a minimum co-efficient in the direction
parallel to the fibres, and a maximum one
transversally ; 3, that it has a very sn-all co-
efficient of dilatation by imbibition in the direc-
tion of the fibres, and a very large one transversally ;
4, that it is a better conductor along the fibres and
transversally ; and 5, that it has the power of con-
siderably retarding electric currents. Mr. Goold
has measured the longitude betwean Valentia, Ire-
land, and Heart's Content, Newfoundland, by
means of the Atlantic cable, and found it to be 4
hours, 53 min., 54 sec., and 5-10ths of a second.
We find a curious controversy in the Journal des
Connaissances Illedicales. It is well known that
phosphorus exercises a poisonous action on the ani-
mal economy; the question is, how this action takes
place? MA. Woehler and Frerichs say that the
phosphorus is transformed into phosphorus and
hypo-phosphorus acids, and thus causes the noxious
phenomena ; but this is refuted by Sawitsch and
Sehuchardt. Munk. and Leyde suppose it to be con-
verted into phosphoric acid in the stomach; but the
symptoms produced by the latter are not similar to
those caused by natural phosphorus. Most physi-
cians imagine that the original substance is carried
into the blood in its natural state, and there oxi-
dised ; but Dr. Dynkowski proves by experiment
that it is converted into phosphuretted hydrogen
gas. Citric Aid is often adulterated in shops by
the addition of tartaric acid ; M. Blather recom-
mends the following process for discovering the
fraud :—lf the adulterated mixture be treated with
hydro-carbonate of magnesia, a neutral tartrate of
magnesia is formed, which is insoluble. This
method, however, is only available when there is
at least one-fourth of tartaric acid in, and moreover
the liquid must be boiled for a minute or two. If
under such circumstances there is no precipitate,
the citric acid is pure, or at least very slightly adul-
terated.—Bottles may be hermetically closed by
means of gelatine caps. Gelatine mixed with gly-
cerine yields a compound which is liquid when hot,
but becomes solid by cooling, at the same time re-
taing much elasticity. To apply it, all that need be
done is to dip the neck of the bottle into the liquid
mixture ; and by repeating the operation the cap
may be made as thick as we please.