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.

One objection to the machine is the difficulty of learning, which is
considerable, but which presents no danger. This difficulty has been
much exaggerated, for before the present powerful brake was applied it
did require considerable skill to ride it down a steep hill. The way