Page:Popular Science Monthly Volume 90.djvu/576

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��The little trolley boat has sol\/:ed the problem of preventing canal ice from accumulating

Trolley Cars on the Water? Yes; and in New York State

IT seems reasonable to conclude that if the electric trolley boat illustrated were in- troduced into Am- sterdam or Venice, it would soon develop into a practical and popular "jitney boat."

The craft shown is by no means an ex- periment, but was de- signed to break up ice jams and prevent them from clogging the intake canal oi one of the great power companies of Niagara Falls. The ice problem has always worried the water power enterprises at Niagara. Large cakes enter the canal from the Great Lakes. To prevent these from accumulating near the power houses, where they would immediately check the flow of water neces- sary for operation, the boat is used.

The hull of the boat greatly resembles that of a submarine as it is made entirely of steel. Although the craft is only eighteen feet long, it carries a seventy-five horse- power motor which gives it unusual power to buck the huge ice cakes out of the way.

��Increasing the Power of Automobile Engines with Mufflers

GREATER power is secured from an automobile engine if the exhaust gases are completely rather than partially re- moved from the cylinders just before each power stroke. While this can be accom- plished if the motor has but one cylinder it is more difficult when two or more cylinders are employed, for the reason that two or more cylinders are connected through the exhaust manifold. This is due to the over- lapping periods during which the exhaust valves are kept open.

Under such conditions, the resistance or back pressure caused by the gases forced to pass through a muffler tends to make the pressure of the beginning exhaust hold back the gases in the cylinder from which the exhaust is nearly completed. This decreases the volume of new fuel gas and lessens the power from its explosion.

These conditions have been largely over- come by the invention of an Indiana engineer, in which a number of mufflers are employed. In the case of the six-cylinder motor shown in the accompanying sketches two mufflers are used. Each is connected with three cylinders so that successively exhausting cylinders operate through dif- ferent manifolds instead of the same one. By this means, only one exhaust valve is open at a time.

���INTAKE MANIfOLD'

���Each of the mufflers is connected with three cylinders so that successively exhausting cylinders discharge through separate manifolds

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