per cent., that is, the
average load for the whole year is 3.7 per cent. of the maximum demand
on you for current at any one time during that period; or, to put it
in another way, this load factor of 3.7 per cent. would show that your
investment is in use the equivalent of a little over 323 hours a year
on this class of business. This is by no means an extreme case. You
can find in almost every large city customers whose load factors are
not nearly as favorable to the operating company, their use of your
investment being as low as the equivalent of 75 or 100 hours a year.
Take another class of business, that of the haberdasher, or small
fancy goods store. As a rule these stores are comparatively small,
with facilities for getting a large amount of natural light and little
use for artificial light. The load factor as shown by the chart is
about 7 per cent., the use of your investment being not quite twice as
long as that of the office building. Day saloons show an average of 16
per cent. load factor; cafetiers and small lunch counters about 20 per
cent., while the large dry goods stores, in which there is
comparatively little light, have a load factor of 25 per cent. and use
your investment seven times as long per year as the office building.
Power business naturally shows a still better load factor, say 35 per
cent., and the all-night restaurant has a load factor of 48 per cent.

You will see from this that the great desideratum of the central
station system is, from the investors' point of view, the necessity of
getting customers for your product whose business is of such a
character as to call for a low maximum and long average use. This
question of load factor is by all means the most important one in
central station economy. If your maximum is very high and your average
consumption very low, heavy interest charges will necessarily follow.
The nearer you can bring your average to your maximum load, the closer
you approximate to the most economical conditions of production, and
the lower you can afford to sell your current. Take, for instance, the
summer and winter curves of the Chicago Edison company. The curve of
December 20, 1897, shows a load factor of about 48 per cent.; the
curve of May 2, 1898, shows a load factor of nearly 60 per cent. Now,
if we were able in Chicago to get business of such a character as
would give us a curve of the same characteristics in December as the
curve we get in May; or, in other wo