"HAMMELMANN TRICYCLE, 1880 U.S.N.M. No. 309258... photograph No. 784-A; plate 12, a. Patent No. 225010... March 2, 1880, to Charles Hammelmann... for a velocipede. This model shows a tricycle propelled by two foot-operated, spring-returned levers that rock sector racks meshed with ratchet gears on the front-wheel axle. The model... is constructed of metal, with the exception of the wooden saddle. The frame consists of a curved bar at the rear, terminating in a fork at its lower end, and a vertical fork at the front, this fork pivoting in the steering head of the bar. A saddle is attached to the curved bar by means of a spring. At the top of the front fork are the handle bars. An axle at the bottom of the rear fork mounts two wheels... The front wheel... perimeter is grooved as if to mount a solid rubber tire... Mounted on each side of the front-wheel hub are ratchet gears. The wheel and gears rotate as one unit on the stationary front axle. Two foot-operated levers, spring-returned to their upper positions, are pivoted at the lower ends of the front fork... To each lever is attached a rack meshed with a gear that is mounted free on the front axle and next to the ratchet gear on its side of the wheel hub. A pawl on the free gear rotates the ratchet gear and the wheel in a forward direction when the foot lever is depressed. The two levers are independent of each other and are intended to be depressed alternately."