728 |884 |1060|1258|1480|1727
-----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----

By the inspection of this table we can see in condensed form the
coal-cost of any speed as high as twenty miles per hour, and for any
size of vessel from one hundred tons to thirty thousand tons. Let us
find in the left hand column a vessel of 2,500 tons displacement.
Pursuing the line along to the right we find in the second column 8.89
tons of coal, which a steamer of this displacement would burn in 24
hours, if running, as indicated at the head of the column, 6 Nautical
miles per hour.

In the next column, under the head of 7 Nautical miles per hour, we
find that she would burn in one day 14.1 tons; or one and a half times
as much coal to gain one sixth more speed:

Again, at 8 miles per hour she burns 21.1 tons; nearly three times as
much as at six miles:

At 9 miles she burns 30 tons: above twice as much as at 7, and nearly
four times as much as at 6, although the speed is but half doubled:

At 10 miles per hour she burns 41.2 tons; about twice as much as at 8
miles, although the speed is increased only one fourth. At 10 she
burns 34 per cent. more than at 9, although the increase of speed is
only eleven per cent. (_See pages 67 and 68_):

At 11 miles per hour she will burn 54.8 or 55 tons; nearly three times
as much as at 8 miles per hour, and six times as much as at 6 miles
per hour:

At 12 miles per hour she will burn 71.2; about thirty per cent. more
than at eleven miles per hour, although gaining but 9 per cent. in
speed; nearly twice as much as at ten miles per hour, three and a half
times as much as at 8, five times as much as at 7, and above eight
times as much as at 6 miles per hour. It is here seen that to double
the speed the consumption of fuel has increased eight-fold, which
verifies my statements hitherto made on this subject. We have already
seen that to gain two miles of speed on any stated speed, it was
necessary to double the quantity of fuel used.

At 13 miles per hour she burns 90.5 tons. This is burning two and a
fourth times as much coal as if she ran only 10 miles per hour. Now,
at this speed, the steamer will reach Southampton or Liverpool in 10
days and 6 hours, which is equivalent to 10 days and 12 hours burning
fuel, allowing six hours for heating and starting, and which would
make an aggregate consumption of 950 tons of coal for the passage of
this steamer of 2,500 d