It is then, easy to perceive, how this effect on the different places of figures is produced: and it is clear, that with the chain motion just described, it forms the basis of the whole Machine. There is, however, one other process to be mentioned, and as the [2d. figure] is before us, we shall now advert to it. In adding up large sums, we have sometimes to work on the tens, sometimes on the hundreds; which mutations are thus performed: The wheel B, ([fig. 2]) is the same as that B, [fig. 1]; and it turns the square shaft B G, on which the wheels k l slide. The wheel l is to our present purpose. It is now opposite the place of shillings; but by the slide m, it can be successively placed opposite pounds, tens, hundreds, &c. at pleasure: on either of which columns, therefore, we can operate by the chain first described—the wheel B being the common mover.

We shall now turn to [figs. 3 and 4] of [Plate 43], which give another representation of the carrying-mechanism, adapted especially to the anomalous carriages of 4, 12, and 20, in reference to farthings, pence, shillings, and pounds, and then following the decuple ratio.

In [fig. 3], k l represent the two acting wheels of the shaft B G, [fig. 2]; the latter dotted, as being placed behind the former; these wheels, however, are not our present object, but rather the carrying system before alluded to; and described separately, in [fig. 3] of [Plate 42]. A, in [figures 3 and 4] (of [Plate 43]) is the first wheel of this series. It has 12 teeth with three carriage-pins (or plates) a, which jog the carrying-pinion B, at every passage of 4 teeth; thus shewing every penny that is accumulated by the farthings. This is so, because the farthings are marked on the teeth of this first wheel in this order—1, 2, 3, 0; 1, 2, 3, &c. and it is in passing from 3 to 0, that this wheel, by the carriage-pinion B, jogs forward the pence wheel C one tooth: But this pence wheel is divided into 12 numbers, from 0 to 11; and has on it only one carrying-pin (or plate) b; so that, here, there is no effect produced on the third wheel D, until 12 pence have been brought to this second wheel C, by the first, or farthing wheel A. Now, this third wheel D, is marked, on it’s twenty teeth, with the figures 0 to 19, and makes, therefore, one revolution, then only, when there have been twenty shillings impressed upon it by twenty jogs of the carriage-pin b, in the second wheel C. But when this wheel D has made one whole revolution, it’s single carriage-pin c, acting on the small carriage-pinion, like that c d, (but not shewn) jogs forward, by one tooth, the wheel E, which expresses pounds; and having two carriage-pins e f, turns the wheel called tens of pounds, one tooth for every half turn of this wheel E: and as, on all the succeeding wheels, to the left from E—(see [fig. 2], [Plate 42]) there are two sets of digits up to 10, and two carriage-pins; the decuple ratio now continues without any change: and thus can we cast up sums consisting of pounds, shillings, pence, and farthings, expressing the results, in a row of figures, exactly as they would be written by an accountant. The opening, through which they would appear, being shewn in [fig. 1], at the point w, corresponding with the line x y of [fig. 2] in the same [Plate].

I shall only remark, further, that the [figures 3 and 4] in [Plate 43], are of the natural size, founded, indeed, on the use of a chain that I think too large; being, in a word, the real chain de Vaucanson, mentioned in a [former article]: and that the figures of [Plate 42] are made to half these dimensions, in order to bring them into a convenient compass on the Plate.

I would just repeat, that I have not attempted here an arithmetical machine in general; but a Machine fit for the daily operations of the counting-house; by which to favour the thinking faculty, by easing it of this ungrateful and uncertain labour. Had I been thus minded, I could have gone further, in a road which has been already travelled by my noble friend the late Earl Stanhope, (then Lord Mahon) but I took a lower aim; intending in the words of Bacon—“to come home to men’s business and bosoms.”