Fig. 75 is a representation of the class of steam fire engine built by Silsbee, Mynderse & Co., Seneca Falls, N. Y. under Holly's patent.
The boiler is vertical, with vertical water tubes passing directly through the fire. These tubes are closed at the bottom and open at the top, where they pass through a water-tight plate, and communicate with the water in the boiler. The arrangement of the tubes causes a constant current, the water rising on the outside of the tubes as they are heated, and its place being supplied by a current flowing downward through the tube to the boiler. The smoke and flame pass among the tubes up through flues.
Both engine and pump are rotary, and of the same type. They consist essentially of two elliptical rotary pistons, cogged and working into one another in an air-tight case. The pistons fit close to the inside of the case, and gear into each on the line of their conjugate diameters. The action is somewhat similar to the old-fashioned rotary pump, consisting of two cog wheels in gear with, each other, the spaces at the side of the case being filled with water, which at the centre are occupied by the teeth in gear. In Holly's pump, instead of uniform teeth, and depending on the fit of the teeth with the side of the case and with each other for the packing, there are two large teeth in each piston opposite each other, which have slide pistons, and intermediate with these large teeth are small cogs, which continue the motion of the rotary pistons. The machine works very smoothly, and performs the work necessary, in ordinary service, under a pressure of 50 to 60 lbs.
There are many other makers of fire engines in this country; but sufficient examples are given to illustrate the class; so successful have they been, that they are fast superseding hand engines, even in the smaller cities.
Under a paid department, the following is, in the city of Boston, Mass., the comparative cost of running the two kinds of engines, viz.:
| STEAM FIRE ENGINE. | |
| 1 engineer | $720 00 |
| 1 fireman | 600 00 |
| 1 driver | 600 00 |
| 1 foreman of hose | 150 00 |
| 8 hosemen, at $125 each | 375 00 |
| - | -------- |
| 7 men | $2,445 00 |
| Keeping of 2 horses | 315 00 |
| - | -------- |
| Total | $2,760 00 |
| HAND ENGINE. | |
| 1 foreman | $150 00 |
| 1 assistant foreman | 125 00 |
| 1 clerk | 125 00 |
| 1 steward | 125 00 |
| 3 leading hosemen, at $125 each | 375 00 |
| 33 men, at $100 each | 3,300 00 |
| -- | --------- |
| 40 men | $4,200 00 |
Here the engineer, fireman, and driver are constantly employed, the hosemen have other employment in the neighborhood, but all the company sleep in the engine house.
In the city of Manchester, N.H., a steam fire engine company is composed of fourteen men, all told, one of whom, acting as driver and steward, is constantly employed, remaining at the engine house with a pair of horses always ready to run out with the engine in case of an alarm of fire. The other members of the company have other employments, and turn out only on an alarm of fire.
| STEAM FIRE ENGINES. | ||
| "Amoskcag," | Expenditures | $864 32 |
| "Fire King," | " | 855 78 |
| "E.W. Harrington, " | " | 496 09 |