ral mixed with it preserved its moisture at this
depth; but three and a half feet lower, an exposure of 3 1-4 hours
reduced the wood to perfect charcoal, and the ore to magnetic oxide.
The temperature of the upper half of the fire-room, when wood is used,
is lower than in the case of charcoal, from the great amount of heat
made latent by the vapor arising from the wood. In the case of
bituminous coal, Bunsen and Playfair find that it has to descend still
lower before it is perfectly coked.

After the wood is completely charred, or the coal become coked, the
subsequent changes are the same that happen in the charcoal furnaces.

_To be continued._

=ANIMALCULAE IN WATER.=

[Illustration:]

The fact is generally known that nearly all liquids contain a variety
of minute living animals, though in some they are too small for
observation, even with a microscope. In others, especially in water
that has been long stagnant, these animals appear not only in hideous
forms, but with malignant and voracious propensities. The print at the
head of this article purports to be a microscopic representation of a
single drop of such water, with the various animals therein, and some
of the inventors and venders of the various improved filters for the
Croton water, would have no objection to the prevalence of the opinion
that this water contains all the variety of monsters represented in
this cut. But the fact is far otherwise; and it is doubtful whether
these animals could frequently be detected in the Croton water, with
the best solar microscope. Nevertheless, the fact is readily and
clearly established that the Croton water contains a quantity of
deleterious matter, which is arrested by the filters; and, on this
account, we cheerfully and heartily recommend the adoption of filters
by all who use this water, from either the public or private hydrants.
To this end we would call the special attention of our city readers to
the improved filters noticed under the head of "New Inventions."

=Length of Days.=

At Berlin and London the longest day has sixteen and a half hours. At
Stockholm and Upsal, the longest has eighteen and a half hours, and
the shortest five and a half. At Hamburg, Dantzic, and Stettin, the
longest day has seventeen hours, and the shortest seven. At St.
Petersburg and Tobolsk, the longest has nineteen, and the shortest
five hours. At Toreno, in Finland, the longest day has twenty-one
hours and a half, and the sh