TABULATING MACHINES are mechanisms controlled by perforated cards which are used as mechanical aids to business methods. The first modern device of this class was designed for the automatic tallying or tabulation of statistics ; but with exten sive development modern tabulating machines are capable of auto matically figuring and printing a report based on the information given to it in the form of perforations in cards or tape. Soon after the introduction of the Jacquard loom, in which the hooks lifting the warp threads were controlled by cards perforated to the desired pattern, Charles Babbage applied the principle to a calcu lating mechanism. Between 1834-54 he designed and partly built an "analytic engine" in which both the amount to be operated upon and the nature of the operation were entered by perforated cards. His machine was never completed. Development of the modern tabulating machine was accomplished by H. Hollerith.
Hollerith's first contribution was a means of tallying census returns through electrical reading of the data punched on cards and accumulating the totals in separate registers. The system was successfully used in the U.S. Census of 1890. During the next decade notable improvements were made including automatic feeding of the cards under brushes for reading and a machine for sorting the cards rapidly into desired groupings. Consequently the 12th U.S. Census in 1900 furnished particularly outstanding evi dence of the possibilities of the system. The population volume was ready one year and seven months from the start of enumera tion; whereas it was estimated that hand tabulation of the three factors alone of sex, nativity and occupation would have required the services of Ioo clerks for seven years and II months. Since 1901 its commercial utility has been greatly increased. Whenever a transaction involves a number of amounts which are subse quently to be used as units two or more times in compiling various totals, it has been found to be generally economical to "translate" it on to a perforated card. If, for instance, the data connected with the cost of production of a certain part are recorded on a card this can then be used in computing totals of individual wages, de partment costs, machine costs, productive hours, etc. The tabulat
ing method is now to be found in general use throughout the world.
The card upon which the data are recorded in the form of perforations has a column for each number or symbol to be entered. The digits o to 9 are denoted by holes punched propor tionate distances from the bottom edge of the card starting with the 9 position. Above the o position is space for two additional perforations which are used principally for actuating certain con trol operations of the machine. These additional positions may also be used for special classification numbers or, in combination with perforations in the regular digit position, to denote alphabetical. characters. The card is divided vertically into "fields" each de noting a particular fact of the total information recorded. Certain information is descriptive while other is quantitative. The former class controls sorting and indicating, while the latter represents amounts to be totalled. Sorting and totalling are accomplished by different machines. Three separate mechanical devices are neces sary to the system : a perforating machine or punch, a sorter and a tabulator. The ordinary form of perforating machine has a set of 12 punches under which the card is advanced a column at a time. By means of a skip bar or stops, certain fields can be skipped where no punching is to be done. There are also more complete types of perforating machines arranged to permit auto matic duplication of information already on one card on to others, to "gang" punch any predetermined number of cards with identi cal data, to number cards consecutively as they are punched. The speed with which trained operators can perforate the cards depends on the nature of the information being recorded as well as its extent. An output of 35o punched cards per hour might be considered an average performance.