With the introduction of the key-set crank-operated feature on the Felt Comptometer, the key action, like in the Burroughs recorder, became a feature to be considered; but unlike the organism of the Burroughs, the Felt construction allowed of the use of a self-correcting keyboard without the possibility of error occurring from its use. This feature is shown in a patent issued to Felt & Wetmore applied for December 27, 1904, and issued May 14, 1907. The patent number is 853,543, and provides a means of correcting errors made in setting the keys by merely depressing the proper key or keys, which will release any previously set in the respective orders. [Sidenote: _Split keyboard_] In some classes of recording it is desirable to print more than one column of items without shifting the paper carriage laterally. A means providing for such an emergency is shown in patent No. 825,205, issued to C. W. Gooch July 3, 1906. The patent was applied for December 2, 1905, and shows a means applicable to any order that may intercept the printing of the ciphers in that order, and thereby the ciphers in all other orders to the right from any key depression to the left of such order. This made what has been generally known as the split keyboard, but differs from that now in general use in that it was set to certain orders and not selective at the will of the operator. [Sidenote: _Dual action keyboard_] With the coming of the motor-operated recording-adders, the extra time allowed the operator, through being relieved of having to work the crank back and forth, left a lapse of time until the motor finished its cranking of the machine. In other words, there could be no gain in the speed of operation because it took as much time for the motor to operate the machine as it did by human power. In a patent granted to McFarland, No. 895,664, applied for October 19, 1905, is shown a means for utilizing the lapse of time which the operator was formerly obliged to lose while waiting for the motor to finish its operation of cranking the machine. It is shown in combination with the keyboard of the Pike recorder and consists of a change that allows the keys for the next item to be set while the motor is cranking the machine to print and add the item previously set, thus utilizing the time formerly lost. [Sidenote: _Non-add signal_]