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 (11,088 - 6,134) / 4,954 = 87.5 per cent. --_eighty-seven and one-half per cent_., or a saving in dollars and cents of four thousand nine hundred and fifty-four dollars ($4,954). In this city, Philadelphia, no allowance for the consumption of water is made in the case of first class engines, such engines being charged the same rate per annum per horse-power as an inferior engine, while, as shown by the above example, a saving in water of _thirty-one and four-tenths per cent_. has been attained by the employment of a first-class engine. The builders of such engines will always give a guarantee of their consumption of water, so that the purchaser can be able in advance to estimate this as accurately as he can the amount of fuel he will use. * * * * * RIVER IMPROVEMENTS NEAR ST. LOUIS.