CHAPTER XVIII.

THE SHIFTING-LINK 229

Early Reversing Motions.--Invention of the Link.-- Construction of the Shifting Link.--Action of the Link.-- Valve-motion of a Fast Passenger Locomotive.--Effect of changing Valve-travel.--Weak Points of the Link-motion.-- Why Decreasing the Valve-travel Increases the Period of Expansion.--Influence of Eccentric Throw on the Valve.-- Harmony of Working-parts.--Adjustment of Link.--Slip of the Link.--Radius of Link.--Increase of Lead.