TROUBLE WITH THE VALVE-MOTION.
However well each may understand his business, in one respect all engineers are in perfect harmony; that is, in hating to encounter trouble with the valve-gear on the road. The valves being the lungs of the machine, any injury or defect to their connections strikes at a vital organ. With a good valve-motion, and valves properly set, the steam is distributed so that nearly an equal amount is admitted through each part in regular rotation; the release taking place in even succession. This makes the exhaust notes uniform in pitch and period. A sudden departure from this uniformity indicates that something is wrong with the valve-motion. It should be the signal to stop, and institute a searching examination. In doing so, avoid jumping at conclusions regarding the cause of the irregularity, and coolly examine, separately, each part whose motion influences the valve-travel.