It will be noticed that the card contains different columns of names or numbers and that there are twelve classifications possible in each vertical column in which a punched hole may be made. Ordinarily the different columns are used for different subjects, and the position of the punched hole in each column records the classification of the data relating to that particular subject. ■' .

The punched cards are stacked so that all are right-side up. It will be noticed from Fig. 228 that the lower right-hand corner of the card

GRAPHIC METHODS

Needles connected to electric wires

is clipped off. If any card in the stack is arranged improperly, it will show because the card will project beyond the other cards at the clipped corner of the pile. The stacks of cards are run through a sorting machine such as is seen in Fig. 229. make a contact through the holes in the card, and operate the sorting mechanism automatically in such manner that the cards are dropped into compartments in accordance with the position of the punched hole on the card. Cards are sorted for one particular characteristic at a time, so that all cards having that characteristic are obtained for tabulating purposes. After the data on one set of cards have been tabulated, the cards can then be run through the sorting machine again and sorted for other characteristics. This permits using the punched cards over and over again until all of the different data which may be of interest have been taken from the cards by the tabulating machines.