L. F. MENABREA ON BABBAGE’S ANALYTICAL ENGINE. 689 
sesses; for such or such a process which might be very easy for 
a calculator, may be long and complicated for the engine, and 
vice versd. 
_ Considered under the most general point of view, the essen- 
tial object of the machine being to calculate, according to the 
laws dictated to it, the values of numerical coefficients which it 
j is then to distribute appropriately on the columns which repre- 
sent the variables, it follows that the interpretation of formule 
and of results is beyond its province, unless indeed this very 
interpretation be itself susceptible of expression by means of the 
_ symbols which the machine employs. Thus, although it is not 
_ itself the being that reflects, it may yet be considered as the 
_ being which executes the conceptions of intelligence*, The 
_ eards receive the impress of these conceptions, and transmit to 
_ the various trains of mechanism composing the engine the orders 
necessary for their action, When once the engine shall have 
been constructed, the difficulty will be reduced to the making 
out of the cards; but as these are merely the translation of alge- 
braical formulz, it will, by means of some simple notations, be 
_ easy to consign the execution of them to a workman, Thus the 
_ whole intellectual labour will be limited to the preparation of the 
- formulz, which must be adapted for calculation by the engine, 
Now, admitting that such an engine can be constructed, it 
may be inquired; what will be its utility? To recapitulate ; it 
will afford the following advantages:—First, rigid accuracy. 
We know that numerical calculations are generally the stum- 
bling-block to the solution of problems, since errors easily creep 
into them, and it is by no means always easy to detect these 
Now the engine, by the very nature of its mode of act- 
ing, which requires no human intervention during the course of 
its operations, presents every species of security under the head 
_of correctness ; besides, it carries with it its own check; for at 
the end of every operation it prints off, not only the results, but 
likewise the numerical data of the question; so that it is easy 
to verify whether the question has heen correctly proposed. 
Secondly, economy of time: to convince ourselves of this, we 
need only recollect that the multiplication of two numbers, con- 
sisting each of twenty figures, requires at the very utmost three 
minutes. Likewise, when a long series of identical computations 
is to be performed, such as those required for the formation of 
* See Note G, 
222 
