Provided there are no faults in the escapement, pivots, or jewel holes, the adjusting of a watch in positions is mainly a question of exact poise of the balance. The balance, with its pivots perfectly clean, should be placed on a poising tool and carefully tested. In a plain balance, tiling the inside under edge of the rim will poise it. In a compensation balance, small errors can be altered by manipulating the four " quarter screws ' - that is, those with long taps. Larger errors must be corrected by altering the weight of the screws. When perfectly poised, the watch will be very nearly correct in different posi-tions. A loss in any one position generally indicates that when the movement is held in that position, and the balance is at rest, the top of the balmce rim is too heavy.