Two pipes were afterwards substituted, of 7-8 inch in diameter; then four of 5-8 inch in diameter ; and the effectspro duced in each instance was as nearly as possible equivalent to that obtained by the 15 inch. jet.
The average working power of the en gine is between 80 and 90 tons of water per hour.
The consumption of coke is about three bushels.
For the supply of the great quantity of water necessary for the engine, cast iron suction-pipes are to be laid under the pavement, with plugs to which the, suction of the engine may be fixed. In consequence of this the en gine may be used as well for extinguish ing fire itself as for supplying other en gines with water. As there are 400 ft. of hose belonging to it, the water may even by that means be conveyed to great dis tances; and a large plane may be protect ed by placing the engine into a circle, the radius of which is 400 feet. This power ful engine requires an engineer, a stoker, and 1 to 4 men to attend to the hose. It eaves the strength of 42 to 105 inen, 40-• cording to its size from 6 to 15 horse power, It does not tire, works regu larly, and requires no relief.
&epees Rotatory Fire Enne is on the rotative princ, gi iple, worked by 16 men, with 11 inch lever. It discharges through a 4 inch pipe, more water than three 8 inch cylinders, with 9 inch strokes, and 15 inch lever, worked by 84 men— and as much water as four 61 inch cylin ders, 9 inch strokes, worked by 36 men with 24 inch lever. This experiment was made at New-York, in September, 1827. The same engine with 12 men, 11 inch lever, threw more water than 2 en gines, worked by 36 men, with 24 inch lever.
A rotative engine, with 20 men, exert ing an estimated power of 35 lbs. per man, with 7 inch lever, has thrown from an inch pipe, 156 ft. horizontal, and 109 ft. in height.
A rotative engine, with 8 men, exert ing an estimated power of 50 lbs. per man, has thrown from a half-inch pipe, 148 ft. horizontal, and 103 ft. in height. The quantity of water discharged by the first engine was 525 gallons for each 1 10 revolutions. By the second, 304 gal Ions, each 100 revolutions. By the third, 128 gallons, each 100 revolutions.
In the first engine the revolving cylin der was 13 inches long and 8 inches in diameter, and the surface acting upon the water was 40 square inches. In the second the revolving cylinder was 12 inches long and 61 inches in diameter, and it had a surface of 80 square inches. The third cylinder was 9 inches long, 5 inches in diameter, and 18 square inches acting surface.
It raised double the quantity of water, since in working the old engines, to dis charge the chamber or cylinder once, the piston must pass twice through it ; an ascending stroke to create a vacuum, and a descending one to force the water. Half the time is consequently lost. In the rotative, a continued vacuum is created, and a continued discharged effected.
It works with one-half the power, since the air-vessel is totally dispensed with ; and the power is applied directly upon the water. It operates on no more than it discharges. On the other hand, as a consequence of the alternating mo tion of the piston engines twice the sur face is acted on, and the friction of course is comparatively twofold.