Note 52 — Chapter IV

In this case it will be observed the table tilted only once for each letter. The method adopted (after trial of the alternative) in my own experiments, though slower and more cumbrous, was apparently productive of more accurate results. It will be readily understood that it might be easier for the transmitted impulse to check a movement, at once uncertain and spasmodic, which had been already initiated, than to overcome, in a short space of time, the resistance of inertia and generate a new movement. The distinction may perhaps be illustrated by the difference between the amount of force required to start a railway truck at rest on the level, and that which would suffice to arrest one actually in gentle motion.