Underlayment is used to absorb minor imperfections in the sub-floor, to deaden the noise when walking on the floor and reduce overhead sound in rooms below.
By means of suitable and simple mechanism this vertical movement of the cylinders works plunger pistons in a pair of cylinders which contain glycerin, and these deaden the vibrations of the machinery while weighing is going on.
The horror aroused by this crime did not long deaden the feeling, at least in official circles, that something must be done to introduce the principle of heredity, as the surest means of counteracting the aims of conspirators.
To deaden the vibration of the springs after a load has been placed on the platform, and thus to enable the weights and values of the goods to be read rapidly, the piston of a glycerin cylinder is attached to the end of the lever which pulls upon the hook of the horizontal bar and is worked by it in the glycerin.
In order to deaden the vibrations of the index arm when weighing goods a vertical rod is attached to the lever from the lever machine near its left-hand end, and this rod carries on its lower end a plunger which works in a closed cylindrical dash-pot containing oil or glycerin.