As indicated by the “Patent Pinion” marking on the barrel bridge, the Waltham’s Model 1870 Crescent Street features a center safety pinion, an inclusion that was gaining in popularity during the time of production. The primary objective of the safety pinion is to protect the train from sudden shock when the mainspring breaks. Without a safety pinion, the force of the mainspring recoil would be exerted directly from the barrel to the center pinion, and subsequently throughout the train. This action would frequently result in damage to the pinion teeth, wheels, and jewels. The safety pinion is brilliantly designed to loosen when such a force is exerted, saving the train from absorbing the sudden shock. Tomorrow, we will begin a closer look at Charles W. Fogg’s patented safety pinion fitted in the Model 1870 Crescent Street.