pencil, or of crayon, 3 cm. long, and attach it to a Cu wire
(Fig. 9). Put into this a piece of S as large as a pea, ignite it
by holding in the flame, and then hold it in a receiver of O.
Note the color and brightness of the flame, and compare with the
same in the air. Also note the color and odor of the product. The
new gas is SO2. Name it, and write the equation for its
production from S and O. How do you almost daily perform a
similar experiment? Is the product a supporter of combustion?

25. Combustion of Phosphorus.

Experiment 16.--With forceps, which should always be used in
handling this element, put a bit of P, half as large as the S
above,into the crayon, called a deflagrating-spoon. Heat another
wire, touch it to the P, and at once lower the latter into a
receiver of O. Notice the combustion, the color of the flame and
of the product. After removing, be sure to burn every bit of P by
holding it in a flame, as it is liable to take fire if left. The
product of the combustion is a union of what two elements? Is it
an oxide? Its symbol is P2O5. Write the equation, using symbols,
names, and weights. Towards the close of the experiment, when the
O is nearly all combined, P2O3 is formed, as it is also when P
oxidizes at a low temperature. Name it and write the equation.

26. Combustion of Iron.

Experiment 17.--Take in the forceps a piece of iron picture-cord
wire 6 or 8cm long, hold one end in the flame for an instant,
then dip it into some S. Enough S will adhere to be set on fire
by holding it in the flame again. Then at once dip it into a