The easiest way to tell whether a lever watch is in beat is to wedge the fourth wheel to take off the power, and allow the balance to come to rest in its natural position. The lever should then be exactly in the centre, between the banking pins or studs. To set a Geneva lever in beat, turn the hairspring collet round upon the balance staff by inserting the thin blade of a watch oiler or something similar in the slit in the collet. Being out of beat would not cause the watch to lose, but it might be caused by the hairspring having too much play between the curb pins. If it cannot be traced to this cause, the hairspring must be shortened by re-pinning in the stud, and the watch again set in beat.