One of the Early “Comptographs” 130 Photo of Gottfried Wilhelm Leibnitz 132 Leibnitz Calculator 133 From Drawings of Burroughs’ Patents Nos. 504,963 and 505,078 136 Burroughs’ Recorder 137 From the February 1908 Issue of Office Appliances Magazine 142 The High-Speed Calculator 148 Two Pages from Wales Adding Machine Co. Booklet 165 Moon-Hopkins Billing and Bookkeeping Machine 176 Napier’s Bones 179 From Drawings of Barbour Patent No. 130,404 180 Photo of John Napier 181 From Drawings of Bollee Patent No. 556,720 186 The Modern Accounting Machine The term “adding machine” or “calculating machine” to most of us represents the machine we have seen in the bank. The average person is not familiar with the different types of accounting machines, to say nothing of the many uses to which they are put; but he has a vague idea that to hold any value they should produce a printed record, he doesn’t know why and he hasn’t stopped to reason why; but those he has seen in the bank do print, and any machine the bank uses, to his mind, must be all right. There are, of course, people who do know the different types of accounting machines, and are familiar with their special uses, but there are very few who are familiar with the true history of the modern accounting machine. [Sidenote: _General knowledge lacking_] Articles written by those not familiar with the true facts relative to the art of accounting machines have wrought confusion. Their errors have been copied and new errors added, thus increasing the confusion. Again, claims made in trade advertisements and booklets are misleading, with the result that the truth is but little known. These facts, and the psychological effect of seeing a certain type of machine in the bank would lead the average man to believe that the recording-adding machine was the only practical machine; and also (as someone stated in the December, 1915, issue of the Geographic Magazine) that Burroughs was the inventor of the recording-adding machine. Although the history of accounting machines dates way back into the tenth century, the modern accounting machines are of quite recent origin, and are especially distinguished by the presence of depressable keys. The keys in these machines act as a means of gauging the actuation which determines the value in calculation, whether the machine is key-driven or key-set with a crank or motor drive. These modern machines, which come within the classification of key-driven and key-set, have their respective special uses. [Sidenote: _Key-driven machine first of the modern machines_]