The means for the carry of the tens consist of a series of teeth i, formed by the bent end of a pivoted spring-pressed lever arm which is pivoted to the inside of the actuating drum with the tooth protruding through a slot in the drum, so arranged as to allow motion of the tooth in a direction parallel to the drum axis. [Illustration] [Illustration: From Drawings of Pottin Patent No. 312,014] Normally these teeth are held in a position to escape engagement with the intermediate gears G, but provision is made for camming the teeth i, to the left into the path of an intermediate gear of one order as the type or register wheel of the lower order passes from 9 to 0. The parts which perform this function are the cam m, located on the left side of each wheel, the plunger M, which operates in the fixed shaft H, and which has a T-shaped head that, when projected into the path of the carrying teeth i, serve to cam them sidewise and bring about the engagement referred to, which results in the higher type or numeral wheel being stepped forward one space. The cam-lugs j on the drum serve to engage and push back the T heads of the cam plungers M, after they have brought about the one-step movement of the higher wheel. [Sidenote: _Baldwin’s printing mechanism_] The printing device consists of a hand-manipulated frame pivoted to the main frame of the machine by the shaft t. The paper is supplied from a roll about the shaft t, and an ink-ribbon is fed back and forth from the rolls u and u¹ over bars of the printing-frame which protrude through slots in the casing and act as platens for the impression of the paper and ink-ribbon against the type. It is presumed that the paper was torn off after a record was printed in the same manner as in the more modern machines. THE POTTIN MACHINE Eight years after the Baldwin patent was issued, a Frenchman named Henry Pottin, residing in Paris, France, invented a machine for recording cash transactions, which he patented in England in 1883 and in the United States in 1885 (see illustration on opposite page). The form and design of the machine, as will be noted, correspond quite favorably with the scheme of the present-day cash register, although it lacks the later refinement that has made the cash register acceptable from a visible point of view. [Sidenote: _First key-set crank-operated machine and first attempt to record the items in addition_] The Pottin invention is named here as the first in which two of the prime principles of the recording-adders of today are disclosed; one is the depressable key-set feature and the other is the recording of the numerical items. The Pottin machine was the first known depressable key-set crank-operated machine made to add columns of figures and the first machine in which an attempt was made to print the numerical items as they were added.