s before, and getting the connections wrong. To prevent this mistake,
make a chart of the "series" coils as you take them off.

To make the task of over-compounding your own dynamo even more simple,
write to the manufacturers, giving style and factory number of your
machine. Tell them how much voltage rise you wish to secure, and ask
them how many turns of "series" wire should be wound on each spool in
place of the old "series" coil. They could tell you exactly, since
they have mathematical diagrams of each machine they make.

Avoid overloading an over-compounded machine. Since its voltage is
raised automatically, its output in watts is increased a similar
amount at the switchboard, and, for a given resistance, its output in
amperes would be increased the same amount, as can be ascertained by
applying Ohm's Law. Your ammeter is the best guide. Your machine is
built to stand a certain number of amperes, and this should not be
exceeded in general practice.

CHAPTER VIII

WIRING THE HOUSE

The insurance code--Different kinds of wiring described--Wooden
moulding cheap and effective--The distributing panel--Branch
circuits--Protecting the circuits--The use of porcelain tubes and
other insulating devices--Putting up chandeliers and wall
brackets--"Multiple" connections--How to connect a wall
switch--Special wiring required for heat and power circuits--Knob
and cleat wiring, its advantages and drawbacks.

The task of wiring your house is a simple one, with well-defined rules
prescribed by your insurance company. Electricity, properly installed,
is much safer than oil lamps--so much so indeed that insurance
companies are ready to quote especial rates. But they require that the
wiring be done in accordance with rules laid down by their experts,
who form a powerful organization known as the National Board of Fire
Underwriters. Ask your insurance agent for a copy of the code rules.

Danger of fire from an electric current comes from the "short
circuit," partial or complete; and it is against this danger that the
rules guard one. The amount of electricity flowing through a short
circuit is limited only by the fuse protecting that line; and since
there is no substance known that can withstand the heat of the
electric arc, short circuits must be guarded against. Happily the
current is so easily controlled that the fire hazard is eliminated
entirely--something which cannot be done wit