the lamp slightly in motion, with the hand, so as not to break
the t.t. by over-heating in one place. Heat the mixture strongly,
if necessary. The upper part of the t.t. is filled with air:
allow this to escape for a few seconds; then move a receiver over
the orifice, and fill it with gas. As soon as the lamp is taken
away, remove the d.t. from the water. The gas contracts, on
cooling, and if not removed, water will be drawn over, and the
t.t. will be broken. Let the t.t. hang on the r.s. till cool.

With glass plates take out the receivers, leaving them covered,
mouth upward (Fig. 8), with little or no water inside. When cool,
the t.t. may be cleaned with water, by covering its mouth with
the thumb or hand, and shaking it vigorously.

What elements, and how many, in KClO3? In Mn02? It is evident
that each of these compounds contains O. Why, then, could we not
have taken either separately, instead of mixing the two? This
could have been done at a sufficiently high temperature. Mu02
requires a much higher temperature for dissociation, i.e.
separation into its elements, than KClO3, while a mixture of the
two causes O to come off from KClO3 at a lower temperature than
if alone. It is not known that Mn02 suffers any change.

Each molecule of potassium chlorate undergoes the following
change:--


Potassium Chlorate = Potassium Chloride + Oxygen
KClO3 = KCl + 3 O.