Hence they are very commonly made unstable, or " accelerating," i.e.
After the Union its shipping fell off, Jacobite troubles and the American War of Independence accelerating the decline.
Since high average speed on a line with frequent stops depends largely on rapidity of acceleration, the tendency in modern equipment is to secure as great an output of power as possible during the accelerating period, with corresponding increase in weight available for adhesion.
This suggests that the retardation may be in great part compensated by some accelerating cause, the existence of which is not yet well established.
Choiseul was the means of accelerating this revolution, not only by his abandonment of diplomatic traditions, but still more by his improvidence and violence.