L. F. MENABREA ON BABBAGE’S ANALYTICAL ENGINE, 681 
Cards of the 
¥ Variable cards. 
operations. 
Columns 
Columns acted |that receive! Indication of Statement of results. 
on by each the result | change of value 
operation. of each on any column, 
operation. 
Number of the operations 
Number of the 
Operation cards. 
Nature of each 
operation. 
IV, =mn’ 
IV, =m'n 
IV, =dn! 
IV, =d’n 
Wig—aom 
1V,,=d mi! 
1Vig=mn'—m' n 
ly ,=d 1! —d! n 
1 
2 
3 
4 
5 
6 
7 
8 
9 
1V,,=d’m—d mi’ 
dn’—d'n 
mni—m'n 
d’m—dm' 
mn! —in' n 
te bdo dd tbe gd dea dd td 
RIS SY 
Vis = 
IVig= y 
8 
Tn order to diminish to the utmost the chances of error in 
inscribing the numerical data of the problem, they are success- 
ively placed on one of the columns of the mill; then, by means 
of cards arranged for this purpose, these same numbers are 
caused to arrange themselves on the requisite columns, without 
the operator having to give his attention to it; so that his undi- 
vided mind may be applied to the simple inscription of these same 
numbers. 
According to what has now been explained, we see that the 
collection of columns of Variables may be regarded as a store 
of numbers, accumulated there by the mill, and which, obeying 
the orders transmitted to the machine by means of the cards, pass 
alternately from the mill to the store, and from the store to the 
mill, that they may undergo the transformations demanded by 
the nature of the calculation to be performed. 
Hitherto no mention has been made of the signs in the results, 
and the machine would be far from perfect were it incapable 
