Letters to the Editor

TwoJohnDeerePumpJacks.jpg
Left: Two John Deere pump jacks, but with different main housings. The jack at left has “John Deere Tractor Company” cast on the driving disc; the jack at right has “John Deere” cast on the driving disc.Above: A bird’s eye view of the engine and pump jack, coupled.Above: This driving disc is cast only with “John Deere.”