and a chapel, where religious worship is performed. The
quicksilver mines of Idria, a town of Lower Austria, have continually
been wrought for more than 300 years. The vapor which is continually
arising from the mercury is very hurtful to the miners, who seldom
survive many years.

_Abyss_, a gulf, a depth without bottom.

In what state is Mercury usually found?

Either native, or in the form of ore; it is often found mixed with
silver, but more frequently with sulphur in the form of sulphuret,
which is decomposed by distillation. Running mercury is found in
globules, in America, and is collected from the clefts of the rocks.
Mercury has the appearance of melted silver; it is neither ductile nor
malleable in this state; it is a substance so volatile, when heated,
that it may be evaporated like water; it is always seen in a fluid
state, even in temperate climates, as a very small portion of heat is
sufficient to preserve its fluidity. It is used to separate gold and
silver from the foreign matter found with those metals. Calomel, a
valuable medicine, and vermilion, a color, are both preparations of
mercury.

_Globules_, small particles of matter having the form of a
ball or sphere.

What is a Thermometer?

An instrument for measuring temperature. It consists of a fine glass
tube, terminated at one end in a bulb, usually filled with mercury,
which expands or contracts according to the degree of heat or cold. On
the scale of the Fahrenheit thermometer, the freezing point of water
is marked 32 deg. and the boiling point at 212 deg.. In both the Centigrade
and the Reaumur scales the freezing point is at 0, and the boiling
point at 100 deg. in the Centigrade and at 80 deg. in Reaumur's. The invention
of this instrument dates from about the close of the sixteenth
century; but it is not known by whom it was first brought into use.

_Terminated_, finished, ended.

When and by whom were Watches and Clocks invented?

Watches were invented about the year 1500, but who was the inventor is
disputed. They were, however, of little value as time-keepers, before
the application of the spiral spring as a regulator to the balance;
the glory of this excellent invention lies between Dr. Hooke and M.
Huygens; the English ascribing it to the former, the Dutch, French,
&c., to the latter. Some assert that pocket-watches were first made
about 1477, at Nuremberg, in Germany. The most ancient clock of which
w