Ulysses S. Grant mentioned this technology in his personal memoirs, in the context of his childhood. "I kept the horse until he was four years old, when he wen

Ulysses S. Grant mentioned this technology in his personal memoirs, in the context of his childhood. "I kept the horse until he was four years old, when he went blind, and I sold him for twenty dollars. When I went to Maysville to school, in 1836, at the age of fourteen, I recognized my colt as one of the blind horses working on the tread-wheel of the ferry-boat."