The very peculiar method of driving and steering, which seems so puzzling to the novice, especially if he is a good rider of other machines--for in that case he is far worse off than one who has never ridden anything--give the rider, when he is familiar with them, a control over the machine which is still surprising to me. In the first place, the machine will run along straight, backward or forward, so long as the handles are let alone. This automatic straight running is a luxury, for until a deviation has to be made, the steering handles need not be touched, and the rider may, if sufficiently confident, travel with his arms folded or his hands in his pockets. The rigid connection between the cranks and the wheels does away with all the backlash, which is so unpleasant with chain or toothed wheel gearing. There is no differential gear or clutch, but the machine possesses the advantage of the clutch over the differential gear when meeting with unequal resistance on a straight course, for each wheel must travel at the same speed; but, in turning a corner, instead of driving the inner wheel only, which is done by the clutch or both wheels equally, which is the case with differential gear, each wheel is driven, but the outer one more than the inner. At high speeds, the steering of the Otto has this advantage, that whereas, with a given action on a tricyle, the same deviation will be effected in the same _space_ at high as at low speeds, the same action on the Otto will, at high speeds, produce the same deviation in the same _time_ as it does at low speeds; and so instead of becoming more sensitive at high speeds, as is the case with the tricyle, the steering of the Otto remains the same. This is because the steering of the tricycle depends on a kinematical, that of the Otto on a dynamical principle. In another respect, no machine can approach the Otto; at almost any speed the rider can, if there is reason, instantly dismount, by which action he puts on the brakes, and the machine will save him from falling, stopping with him almost instantly. As is well known, we can move backward and forward, we can twist around and around in our own width, or can ride over bricks with impunity.