Many things of common occurrence (says Professor Tyndall) are to be
explained by reference to the quality of inactivity. We will here state
a few of them.
When a railway train is moving, if it strike against any obstacle which
arrests its motion, the passengers are thrown forward in the direction
in which the train was proceeding. Such accidents often occur on a
small scale, in attaching carriages at railway stations. The reason is,
that the passengers share the motion of the train, and, as matter, they
tend to persist in motion. When the train is suddenly checked, this
tendency exhibits itself by the falling forward referred to. In like
manner, when a train previously at rest is suddenly set in motion, the
tendency of the passengers to remain at rest evinces itself by their
falling in a direction opposed to that in which the train moves.