Foreign machines are equipped with from three to five speed-changing gears in addition to the spark control, and many also have throttles for governing the speed of the engine.

Going at full speed down a long hill about two miles out of Canandaigua, we discovered that neither power nor brakes had any control over the machine.  The large set-screws holding the two halves of the rear-axle in the differential gears had worked loose and the right half was steadily working out.  As both brakes operated through the differential, both were useless, and the machine was beyond control.  An obstacle or a bad turn at the bottom meant disaster; happily the hill terminated in a level stretch of softer road, which checked the speed and the machine came slowly to a stop.

The sensation of rushing down hill with power and brakes absolutely detached is peculiar and exhilarating.  It is quite like coasting or tobogganing; the excitement is in proportion to the risk; the chance of safety lies in a clear road; for the time being the machine is a huge projectile, a flying mass, a ton of metal rushing through space; there is no sensation of fear, not a tremor of the nerves, but one becomes for the moment exceedingly alert, with instantaneous comprehension of the character of the road; every rut, stone, and curve are seen and appreciated; the possibility of collision is understood, and every danger is present in the mind, and with it all the thrill of excitement which ever accompanies risk.

During the entire descent the Professor was in blissful ignorance of the loss of control.  To him the hill was like many another that we had taken at top speed; but when he saw the rear wheel far out from the carriage with only about twelve inches of axle holding in the sleeve, and understood the loss of control through both chain and brakes, his imagination began to work, and he thought of everything that could have happened and many things that could not, but he remarked philosophically,—­

“Fear is entirely a creature of the imagination.  We are not afraid of what will happen, but of what may.  We are all cowards until confronted with danger; most men are heroes in emergencies.”

Detaching a lamp from the front of the carriage, repairs were made.  A block of wood and a fence rail made a good jack; the gear case was opened up, the axle driven home, and the set-screws turned down tight; but it was only too apparent that the screws would work loose again.

The next morning we pulled out both halves of the axle and found the key-ways worn so there was a very perceptible play.  As the keys were supposed to hold the gears tight and the set-screws were only for the purpose of keeping the axle from working out, it was idle to expect the screws to hold fast so long as the keys were loose in the ways; the slight play of the gears upon the axles would soon loosen screws, in fact, both were found loose, although tightened up only the evening before.