One of the salient features connected with this device is its ability to compute only the actual time worked in the factory irrespective of the times of registration. That is to say, in a factory working ten hours a day from seven to twelve and one to six the elapsed time will only be computed during these hours. Any registrations made before seven o'clock will not begin to count elapsed time until that hour, and the computation of elapsed time automatically stops at noon to be resumed at exactly one o'clock, and then continues until quitting time at night, when again it stops automatically. The clock movement, however, does not stop, but always shows the correct time exactly the same as the master clock, and is entirely unaffected by the elimination of the non─working hours in figuring the elapsed time. The machine can also be set to record overtime at night if so desired. In case work on a given job is not completed on the day it is begun, it is not necessary to ring out on the elapsed time machine until the job is completed as the machine computes up to 100 hours. A job beginning on Monday and running through the week until Saturday night, when it is finished, may be registered on one card, or even for a longer period up to 100 hours. The elimination or cut─out wheel referred to as being a part of the master clock, is responsible for this wonderful piece of work. The wheel makes one revolution in twenty─four hours and is graduated in fifteen minute divisions for the purpose of setting the contact breakers. The contact breakers are bits of hard rubber which are fastened around the rim of the wheel, and may be moved about at the will of the custodian of the apparatus by simply loosening the set screw. These blocks are set on the starting and stopping time and when they pass the contact breakers the electrical circuit is broken, and the computing device started or stopped as the case may be. =15. Cumulative Time Records.= In some factories and shops, the work is of such nature that economy results if the work order and the time record follows the job through all of the operations. For example, hosiery and underwear go through the factory in dozen lots; in a shoe factory a lot of shoes is kept together until every operation is finished; in a harness factory, a bridle goes through all operations on one work order; in a machine shop, one or more rough castings may pass through several operations in the process of converting them into finished parts. [Illustration: Fig. 23. Calculagraph Time Card with Coupons] When these conditions exist, it is practical to attach a time card to the work, and to accumulate the time of all employes for the entire job. At the same time, individual time records are obtained.