Postmasters prepare, for the guidance of carriers in their work, a time schedule made on the basis of eight hours’ work each day, and so arranged as to provide only such time as is absolutely necessary for the legitimate office duties of each carrier. The hours of daily service need not be consecutive. No carrier is scheduled for more work than he can perform during eight hours. Carriers need not be required to consume exactly eight hours each day, but as nearly such time as practicable, considering the varying amount of mail to be handled on different days. Postmasters must not direct or permit carriers to work overtime, and are held accountable therefor. Letter carriers must not report prior to schedule time for the first trip of the day, nor for the beginning of a trip following a “swing.” Carriers must not remain at their desks nor in the working room of the office during a “swing” or interval between trips, nor during the dinner hour; neither must they remain in the post office after completing the last trip of the day. Carriers engaged exclusively in the collection service must not remain in the workroom of the office except while depositing and facing the mail collected by them. Carriers must register on the automatic clock register upon reporting, leaving, returning and ending for each trip which begins and ends at the post office. The time from the clock tapes is copied into the time book or pasted into a suitable book and preserved, and constitutes the official record of time. Should the clock register be out of order the time recorded by carriers on their daily trip reports is entered in the time book. One carrier must not register on the clock for another. If this rule is violated both the carriers concerned will be removed. The time of reporting, leaving, returning and ending for each trip must also be recorded by the carriers on their daily trip reports; the entries on these reports must be made at the beginning and end of each trip, and must not be deferred until the close of the day. When collections are made in the morning, on the carrier’s way to the office, the first and second entries on the trip report must be the time of opening the first box. When a carrier completes his delivery on his route and does not return to the post office the time recorded on his trip report for returning and ending on that trip must be the time of his last piece of mail.