It will be perceived that every unit added to in , entails an additional repetition of operations (13 ... 23) for the computation of . Not only are all the operations precisely the same however for every such repetition, but they require to be respectively supplied with numbers from the very same pairs of columns; with only the one exception of Operation 21, which will of course need (from ) instead of (from ). This identity in the columns which supply the requisite numbers, must not be confounded with identity in the values these columns have upon them and give out to the mill. Most of those values undergo alterations during a performance of the operations (13 ... 23), and consequently the columns present a new set of values for the next performance of (13 ... 23) to work on. At the termination of the repetition of operations (13 ... 23) in computing , the alterations in the values on the Variables are, that In this state the only remaining processes are first: to transfer the value which is on , to ; and secondly to reduce , , to zero, and to add[30] one to , in order that the engine may be ready to commence computing . Operations 24 and 25 accomplish these purposes. It may be thought anomalous that Operation 25 is represented as leaving the upper index of still = unity. But it must be remembered that these indices always begin anew for a separate calculation, and that Operation 25 places upon , the first value for the new calculation. It should be remarked, that when the group (13 ... 23) is repeated, changes occur in some of the upper indices during the course of the repetition: for example, , would become , and .