Sorting the cards into the desired groups for tabulation is done at the rate of about 400 cards per minute for each digit of the class number. One well known form of sorting machine has 13 pockets, one for each possible columnar perforation and one for "rejects." The tabulator, or accounting machine, which totals the amounts perforated in given fields is capable of several different applica tions. The simplest form of this device consists of a set of counters actuated through a reading mechanism. Two methods of reading the cards are in use : electrical and mechanical. In the former, brushes make electrical contact through the perforations thereby actuating magnets to trip the counters. The mechanical method employs a full set of pins which are brought down upon the card momentarily at rest and which penetrate the perforations to actuate the counters mechanically. Printing tabulators are arranged to either total the cards at high speed—about i so per minute—and then print the total, or list each card individually at slower speed followed by a total for the group. By means of spe
cial control features the machines automatically take totals of several fields after each sorted group and also store the amounts for grand totals. A great deal of flexibility is attainable the way the items and totals may be made to appear on the printed sheet. Mechanism has lately been incorporated accomplishing direct sub traction without the necessity of perforating the complements of the numbers as formerly required. This permits of reports show ing total credit and debit amounts and net balance. By using combinations of two or more holes in a column it is possible to list alphabetical characters as well as numbers. With alphabetical printing, addition or subtraction automatically sensed by the machine, and devices added to the printing section for handling report and bill forms, tabulating machines have become automatic accounting and billing machines. (B. To.)