270

MOTIVE POWER EMPLOYED

effect, is always proportionate to the workformed.

I shall now give two experiments, made witha view of illustrating this in the loco-motiveengines, which may not only be the means ofexplaining the characteristic properties of thosekind of engines, but also of high-pressureengines in general.

EXPERIMENT XXXV.

Loco-motive engine, with two cylinders each9 inches diameter, boiler 9 feet long, 4 feet8 inches diameter, density of steam in theboiler 50lbs. per square inch, length of strokein the cylinders 2 feet, diameter of travelling-wheels 37 inches, same construction as Fig. I.and II. Plate V.

Up the plane, Experiment XXVII., the en-gine dragged 12 loaded carriages, the same astherein described, the distance of 388 yards in430 seconds.

The resistance by the gravity of the engine and carriages, andthe friction of the carriages, as per Experiment XXVII., is18101bs. which was moved over the space of 1164 feet; conse-quently, 1810 X 1164“ 2106840, the effect produced, exclusiveof the friction of the engine.

Then 9 a x .7854 x 2 “ 127.2 square inches, the area of the twocylinders, which, multiplied by 50lbs., the pressure on each squareinch is 6367 lbs., the power applied to the pistons. The diame-ter of the wheels of the engine is 37 [inchest 116.24 inches cir-