s found
to be an exceedingly disagreeable passenger vessel. Propellers have
become deservedly unpopular the world over; and if it were possible
for them to be faster than the side-wheel, it is hardly probable that
first-class passengers would even then go by them, as they are known
to be so exceedingly uncomfortable.

The propeller, I have before said, is erroneously supposed to run more
cheaply than the side-wheel. I think that I have shown that as a mail
packet it will cost more to run it at a given speed. But there are
certain cases in which it does run more cheaply; these are, however,
only where the speed is low, and the machinery not geared, and where,
as a consequence, sail can be used to more advantage than on a
side-wheel. The economy is not the result of the application of the
power by the screw, as compared with the side-wheel, but of the sail
alone; and this economy is more or less, just as canvas is employed
more or less in the propulsion. The screw is the better form of
steamer for using sail; and the low speed at which propellers
generally run, is a means of making that sail more effective. We have
already seen, in the section on the cost of steam, that it generally
requires twice the original quantity of fuel to increase the speed
from eight to ten knots per hour in either style of steamer. Now, it
is a well-known fact that the transatlantic propeller lines are on the
average more than two knots per hour short of the speed of the
side-wheels, which makes their passages across the Atlantic from two
to six days longer than by the mail packets. They thus save from one
half to two thirds of the fuel, and deducting its prime cost from the
bill of expenses, they add to that of receipts the freight on the
cargo, which occupies the space of the coal saved. They consequently
run on much smaller expenses; but only when their speed is less than
that of the side-wheels, and far too low for effective postal
service. Economy thus purchased at the expense of speed may do for
freight, and enable propellers to derive some profits from certain
cargoes; but it can never subserve the purposes of mails and
passengers. It must alway be recollected that the effective speed of
the propeller is reduced just in the ratio of the greater economy as
compared with the side-wheel.

It thus appears that with any appreciable economy the propeller must
be slower than the side-wheel; and that with any considerable economy
it can be but