by the Elector of Bavaria. He went to Europe
in the time of the American Revolution, and, devoting
himself to scientific investigations, became the founder
of the Royal Institution of Great Britain. Davy
was his associate, and, so far as the new views of
heat are concerned, his disciple. He exploded
the notion of caloric, demonstrated experimentally
the conversion of mechanical force into heat, and
arrived at quantitative results, which, considering
the roughness of his experiments, are remarkably near
the established facts. He revolved a brass cannon
against a steel borer by horse-power for two and one-half
hours, thereby generating heat enough to raise eighteen
and three-fourths pounds of water from sixty to two
hundred and twelve degrees. Concerning the nature
of heat he wrote as follows, the Italics being his
own:—“What is heat? Is there
any such thing as an
igneous fluid? Is
there anything that with propriety can be called caloric?
We have seen that a very considerable quantity of
heat may be excited by the friction of two metallic
surfaces, and given off in a constant stream, or flux,
in
all directions, without interruption or
intermission, and without any signs of
diminution
or
exhaustion. In reasoning on this subject,
we must not forget that
most remarkable circumstance,
that the source of the heat generated by friction
in these experiments appeared to be
inexhaustible.
It is hardly necessary to add, that anything which
any insulated body or system of bodies can continue
to furnish
without limitation cannot possibly
be
a material substance; and it appears to me
to be extremely difficult, if not quite impossible,
to form any distinct idea of anything capable of being
excited and communicated in these experiments, except
it be MOTION.”
In style, Professor Tyndall’s work is remarkably
clear, spirited, and vigorous, and many of its pages
are eloquent with the beautiful enthusiasm and poetic
spirit of its author. These attractions, combined
with the comprehensiveness and unity of the discussion,
the range and authenticity of the facts, and the delicacy,
originality, and vividness of the experiments, render
the work at once popular and profound. It is
s classic upon the subject of which it treats.
My Days and Nights on the Battle-Field.
A Book for Boys. By “CARLETON.”
Boston: Ticknor and Fields.
The literature of the war has already reached the
dimensions of a respectable library. The public
mind at the instant of the outbreak felt an assurance
that it was to be one of the memorable epochs of mankind.
However blinded to the significance of the previous
conflicts in the forum and at the ballot-box, there
was a sudden and universal instinct that their armed
culmination was a world-era. The event instantly
assumed its true grandeur.