Q. What is meant by a horizontal compound tandem engine?
A. One cylinder being back of the other with two pistons on the same rod.
Q. What do you understand by lap?
A. Outside lap is that portion of the valve which extends beyond the ports when valve is placed on the center of its travel; inside lap is that portion of valve which projects over the ports on inside or toward the middle of the valve.
Q. Of what use is lap?
A. It gives expansion to the steam in the cylinder.
Q. What is the dead center of an engine?
A. The point where the center of shaft, center of wrist-pin and center of piston rod are in the same straight line.
Q. From what cause do belts have power to drive shafting?