Democratic Sentinel, Volume 7, Number 13, Rensselaer, Jasper County, 27 April 1883 — Vibration. [ARTICLE]

Vibration.

The Boston Advertiser says that it has been well known for many years that when a body of troops crosses a bridge the step must be broken, otherwise the regular tread of such a heavy weight of men will throw the structure into vibrations so violent as to endanger its standing. It is also well known, though it lias not been fully established until recent years, that large buildings have their key-jote, and that factories standing near dams have been put into such vibration by the quivering of the falling water that they have seemed i i actual danger of destruction, so violent has been the oscillatory motion. The explanation is that the particular volume and velocity of the water struck tho keynote of the buMiog, and «jet it is sympathetic vitoatiou.