Operating between the accumulator wheels and the racks of plate B are a pair of gears, one in the form of a lantern wheel loosely mounted on the accumulator wheel shaft but connected thereto by a ratchet wheel and pawl connection; the other, a small pinion meshing with the lantern wheel on a separate axis, protrudes below the carriage into the path of the racks. Thus as the carriage is moved by the reciprocating device connected with the hand-lever K, the pinions of the accumulator will engage whatever racks have been set and the numeral wheels and type wheels will be operated to give the result. The numeral and type wheels have two sets of figures, one of which is used for addition and multiplication, while the other set runs in the opposite direction for negative computation or subtraction and division. A plate arranged with sight apertures covers the numeral or register wheels, while the type wheels are left uncovered to allow a hinged platen F, mounted on the top of the carriage (see Fig. 3), to be swung over on top of them and depressed. Attached to the platen F, are a series of spring clips d, under which strips of paper may be slipped (as shown by D, in Fig. 4), and which serves to hold the paper while an impression is taken. [Sidenote: _Barbour machine not practical_] Thus the Barbour invention stands in the Art as something to show that as early as 1872 an effort was made to provide means to preserve a record of calculations by printing the totals of such calculations. THE BALDWIN MACHINE The next effort in this class of machines is illustrated in a patent issued to Frank S. Baldwin in 1875 (see illustration on opposite page). The Baldwin machine is also of moment as having the scheme found in the machines known as the Brunsviga, made under the Odhner patents--a foreign invention, later than that of Baldwin, used extensively abroad and to a limited extent in this country. The contribution of Baldwin to the Art of recording-calculating devices seems to be only the roll-paper in ribbon form and the application of the ink ribbon. The method used by Barbour for type impression was adapted and used by Baldwin; that is, the hinged platen and its operation by hand. Of the illustrations shown of the Baldwin machine, one is reproduced from the drawings of the patent while the other is a photo reproduction of the actual machine which was placed on the market, but, as may be noted, minus the printing or recording device shown in the patent drawings. [Sidenote: _Description of Baldwin machine_] Referring to the photo reproduction, the upper row of figures showing through the sight apertures in the casing are those of the numeral wheels which accumulate the totals, and which in the patent drawings would represent the type of the accumulator wheels for printing the totals of addition and multiplication or the remainders of subtraction and division. [Illustration: From Drawings of Baldwin Patent No. 159,244]