1830.] Calculating Engine . 97 
cases inventing tools and machinery of great expense and complexity (and in many 
instances of ingenious contrivance, and likely to prove useful for other purposes 
hereafter) for forming, with the requisite precision, parts of the apparatus dis- 
similar to any used in ordinary mechanical works, — that of making many previous 
trials to ascertain the validity of proposed movements, and that of altering, improv- 
ing, and simplifying those already contrived and reduced to drawings. 
Your Committee are so far from being surprised at the time it has occupied to 
bring it to its present state, that they feel more disposed to wonder it has been 
possible to accomplish so much. 
The drawings form a large and most essential part of the work : they are executed 
with extraordinary care and precision, and may be regarded as among the best 
that have ever been constructed. On these all the contrivance has been bestowed, 
and all the alterations made ; so that scarcely any work, excepting drawing, has been 
thrown away. When it is mentioned that upwards of 400 square feet of surface 
are covered with drawings, many of them of the most elaborate description, it will 
easily be understood that a very great expense of time, thought, and capital, must 
have been incurred in producing them ; but without which your Committee consider 
that success would have been impossible. 
Nearly the whole of this department of the work (according to Mr. Babbage’s 
statements, probably nine tenths) is completed, and what remains is of a nature to 
afford no difficulty, on the score of contrivance ; so that there is no reason why the 
execution of the work (hitherto necessarily retarded till the completion of the 
drawings) could not now proceed with rapidity ; and according to what the Com- 
mittee have been enabled to gather from Mr. Babbage’s statements and their own 
observations, and supposing no unexpected cause of delay, they regard a further 
period of three years, as probably sufficient for its completion. 
In judging of the adequacy of Mr. Babbage’s work, to complete the objects for 
which it was intended, these are two distinct questions, — the adequacy of the con- 
trivance, and that of the execution. 
On the former point every information has been afforded by Mr. Babbage ; and 
both the drawings and the work executed have been unreservedly subjected to their 
discussion, and have been such as to excite a well grounded confidence. The move- 
ments are combined with all the skill and system which the most experienced work- 
manship could suggest. 
But in so complex a work, in which interrupted motions are propagated simulta- 
neously, along a great variety of trains of mechanism, it might be apprehended that 
obstacles would occur, or even incompatibilities arise from the impracticability of 
foreseeing all the possible combinations of the parts, and of which, in a mere inspec- 
tion, your Committee could not be expected to form a judgment. But this doubt, 
should it arise, your Committee consider as fully and satisfactorily removed, by the 
constant employment by Mr. Babbage, of a system of mechanical notation, devised 
by himself, and explained in a paper in the Transactions of this Society, which places 
at every instant, the progress of motion through all parts of this or any other 
mechamsm distinctly in view ; and by an exact tabulation of the times required 
for all the movements, renders it easy to avoid all danger of two contradictory 
impulses arriving at the same instant at any part. 
Of the adequacy of the machinery to work, under all the friction and strain to 
which it can ever be fairly exposed, and of its durability, your Committee have not 
the least doubt. Great precautions are taken to prevent the wear of the parts by 
friction, and the strength, solidity, and equilibrium in the whole apparatus, ensure 
it from all danger on the score of violence or constant wear. 
It ought also constantly to be borne in mind, that in all those parts of the ma- 
chine where the nicest precision is required, the wheel-work only brings them, by a 
first approximation (though a very nice one) to their destined places. They are 
then settled into accurate adjustment, by peculiar contrivances, which admit of no 
shake or latitude of any kind. 
The machine consists essentially of two parts, — a calculating part and a printing 
part. These are both equally essential to the fulfilment of Mr. Babbage’s views ; 
lor the whole advantage would be lost, if the computations made by the machine were 
copied off by human hands, and transferred to type by the usual process. The 
actual work of the calculating part is in a great measure constructed, although not 
put together, a portion only having been temporarily fitted up for the inspection of 
the Committee: and from its admirable workmanship, they have been able to form 
a confident opinion that it will execute the w T ork expected from it. At the same 
time the Committee cannot but observe, that had inferior workmanship been re- 
sorted to, such is the number and complexity of the parts, and such the manner in 
