The object of the invention is to quickly and accurately add a column or columns of figures and, at the same time and by the same manipulation of the keys, to print upon a sheet of paper or a blank book these figures in the order in which they are added, so as to form a proof sheet which shall verify the correctness of the addition, and which machine, by special adjustments, may be made to print at the end of the column the sum total of the column, and to do the work in a vertically descending progression or vertically ascending progression or in a horizontal progression.

It verifies, by printing in full sight, each figure to be added at the same time the addition is made, and is so constructed that, if the proper key is struck, the result must be perfect. It works with the ease of a typewriter and its speed is only limited by the skill of the operator. It subtracts by reversing the machine as readily as it adds; in other words, the registering disks run one way as readily as the other. It carries automatically. The keys all work in the same horizontal plane and have for each figure the same dip or extent of depression. Its construction is simple, considering the variety and extent of work done, and its action in all its parts is positive. It is adapted to printing on pass books with the same facility as upon the ordinary platen and sheet. Additions can be made either to the right or to the left. It can be used to add without printing or to print without adding. Mistakes, if made, can be seen at once, and corrected as easily as mistakes upon the typewriter. The illustration represents a double machine, upon one side of which can be kept the debts and on the other the credits, and a balance can be struck by deducting the one from the other as shown in the example given.