Abstract
Most instruments get out of order under mechanical vibration. Hair springs of moving elements often resonate with axial vibration, resulting in zero shift of meters (-10∼-15deg. for example). Pointer shafts get into relative hopping motions with thrust bearings and are rotated by horizontal component of vibration. In the latter case, value of instrumental error easily varies depending on sort and dimensions of bearings, and vibrating conditions, and constant of control spring. With normal thrust bearings of slidng type, this value becomes very large up to about 100deg., sometimes positive and other times negative. It is regrettable that the indicated value generally can not be corrected.
