As with other recorders, one of these machines should be located at a central point in each department. It is advisable to provide a card rack with compartments bearing the employe's numbers, and to place cards for jobs ahead in these compartments. The cards for the day are first sorted by employe's numbers to verify the clock record, and then by job numbers for the use of the cost department. [Illustration: Fig. 20. Time Card Used with the Calculagraph] Another elapsed time recorder, which was placed on the market after the above was put in type, but before this book went to press, is shown in Fig. 21, the form of record being shown in Fig. 22. The device is operated electrically, the impulses being furnished by a master clock. This may be located anywhere in the building, preferably in the office, as it will be less affected by vibration and dust. To the master clock is also fitted the 24─hour elimination or cut─out wheel described later. This clock transmits electric impulses each minute all through the building to the various elapsed time mechanisms. Thus all the machines are exactly the same time and cards may be registered in on one machine and out on any other and correct results obtained. [Illustration: Fig. 21. Elapsed Time Recorder with Master Clock. Manufactured by International Time Recording Co.] The mechanism is about nine inches square and is enclosed in a dust proof iron case. It may be placed on a work bench, on a pedestal, or it may be sunk flush with the top of the bench or desk. The flat cover has two openings or slots for the insertion of the cards. One opening is marked "in" for the first record of a job, the other "out" for registering when the job is completed. There is also an aperture in the cover through which may be seen a series of indicating wheels showing exactly the time of day. There is only one handle to be operated and, therefore, no confusion can occur in the mind of the operator as to which handle to pull. [Illustration: Fig. 22. Time Card Used with the International Elapsed Time Recorder] The cards used in the machine may be of any length desired but can only be of one width, 4¼ inches. In registering in, the card is placed in the front or starting slot, and the lever pulled over. This prints the starting time at the top of the card in the space to the left. At the same time four small holes are punched in the card which individualize the record. After a job is completed the card is placed in the rear or stopping slot, the lever pulled over once more, and the stopping time and actual elapsed time are both printed on the card by one pull of the handle, thus enabling anyone to compare the two records and prove the accuracy of the machine for every record.