THE RETURN CIRCUIT. 5L
pretty high price to pay for the privilege of having a poorly
connected track, liable to cause serious trouble from stray
currents. And this instance represents not at all an ex-
tremely bad case, but a very common one.
The moral of all this is that just as much care should
be spent on the joints underground as on those overhead,
in fact more, since the latter are but slightly liable to cor-
rosion while the former run great risk of it. For this
reason the continuous rail is doubly desirable since it not
only avoids constant loss of energy in the rail joints, but
averts a rather heavy cost of maintenance. With continu--
ous rails some cross bonding may be desirable to give se-
curity against breaks, but it comes into use only in emer-
gencies.
To prevent electrolytic destruction of neighboring con-
ductors by stray current from the rails the best simple ad-
vice that can be given is as follows:
1. Use the continuous rail system; or
2. Bond very thoroughly; put the positive pole of the
dynamo on the overhead line; join the negative directly to
the track without intentional earth connection, and
3. In any case investigate the potential between track
and buried conductors and run supplementary wires from
these conductors to the dynamo if necessary.
This applies to small systems as well as large. The
only cases which may be fairly excepted are electric roads
running through country where there are no buried con-
ductors near, and elevated roads which are really a special
case of the double trolley system. As electric railways
have become more common and more thoroughly under-
stood the conditions of the return circuit have been much
ameliorated, but sins against Ohm’s law are still distress-
ingly common. A feeling still seems to be rife that what
is concealed from the eye may be scamped, as when the
guileful wiring contractor runs underwriters’ wire through
the ceilings and puts okonite at the joints. It is bad
enough for a dishonest contractor to do that sort of thing,
but what shall we say of a man who cheats himself by
