e same rapidity as does
the business. The makers of sewing machines, typewriters, reapers, and
mowers, and indeed machinery generally, can usually increase their
product without correspondingly increasing their outlay. They can make
goods and sell them in a foreign market at rates which would injure
and might even ruin them if they were applied to the sales made in
their own country. This fact is most obvious when the manufacturer's
machinery is not all kept running or when it all runs only a part of
the time. Increasing the output is then a particularly cheap
operation. When a carrier's facilities are partially unused--when a
ship carries a cargo in one direction and returns in ballast, or when
it sails on both trips with its hold only half full--it is ready to
carry additional goods at a low rate provided that this policy will
not demoralize its existing business. In our illustration we have
assumed that some merchandise is made at A and consumed at B, but it
may well be that goods of some sort are produced at B and consumed at
A. There may be stone quarries at B and there may be need of stone for
paving or building at A, and the vessel may carry a return cargo of
this kind at any rate which does not greatly exceed the mere cost of
loading and unloading it and be better off for so doing. If the entire
difference between the cost of the stone at B and the cost of
producing it at A from some other source is a very slight one, the
amount of it still represents all that the ship can get for carrying
the stone. The utmost that the traffic will bear is this difference in
costs; and yet the business will be accepted, for the return exceeds
the merely variable costs which it entails. The fixed charges, the
interest on the cost of the vessel, and the outlay for maintaining it
do not need to be paid in any part from the returns of this extra
business. They are already provided for.

If instead of returning from B with a hold quite empty, the vessel
made both voyages with a hold only half full, the result would be
similar. It would then be in a position to make a low bid for further
freight in both directions. If this entails no cutting of the rates
for carrying the original goods, the vessel can take further goods
with advantage at any rate above the merely variable costs.

_Production which is Advantageous though it does not repay all
Costs._--There are two general conditions under which it is
advantageous, both in making go