These engines were replaced by one first-class automatic engine,
which developed one hundred and forty-two horse-power per hour with a
consumption of _three pounds_ of coal per hour per horse-power, and the
indicator diagrams showed a consumption of _thirty_ pounds of water per
hour per horse-power. Coal cost

((142 x 3 x 24 x 300) / 2,000) x 4.00 = $6,134

Six thousand one hundred and thirty-four dollars. Water cost (142 x
3.00= $426.00) four hundred and twenty-six dollars.

Cost of coal for 300 days. $6,134
Cost of water for 300 days. 426
------
Total cost of coal and water. $6,560

The water evaporated in the latter case to perform the same work was
(142 x 30 x 24 x 300 = 30,672,000) thirty million six hundred and
seventy-two thousand pounds of feed water against (40,320,000) forty
million three hundred and twenty thousand pounds in the former, a saving
of (9,648,000) nine million six hundred and forty-eight thousand pounds
per annum; or,

(40,320,000 - 30,672,000) / 9,648,000 = 31.4 per cent.

--_thirty-one and four-tenths per cent_.

And a saving in coal consumption of