238 Mr. Babbage's Calculating Etigines. 



difficulties of the case, and in the latter part of the same period 

 by the drawings and notations of the Analytical Engine, and the 

 experiments relating to its construction, gave occupation to a 

 considerable number of workmen of the greatest skill. During 

 the many years in which this work proceeded, the workmen were 

 continually changing, who carried into the various workshops in 

 which they were afterwards employed the practical knowledge 

 acquired in the construction of these machines. 



To render the drawings of the Difference Engine intelligible, 

 Mr. Babbage had invented a compact and comprehensive lan- 

 guage (the Mechanical Notation), by which every contempora- 

 neous or successive movement of this Machine became known. 

 Another addition to mechanical science was subsequently made 

 in establishing principles for the lettering of drawings ; one con- 

 sequence of which is, that although many parts of a machine may 

 be projected upon any plan, it will be easily seen, by the nature 

 of the letter attached to each working point, to which of those 

 parts it really belongs. 



By the means of this system, combined with the Mechanical 

 Notations, it is now possible to express the forms and actions of 

 the most complicated machine in language which is at once con- 

 densed, precise and universal. 



At length, in November 1842, Mr. Babbage received a letter 

 from the Chancellor of the Exchequer, stating that Sir Robert 

 Peel and himself had jointly and reluctantly come to the conclu- 

 sion that it was the duty of the Government, on the ground of 

 expense, to abandon the further construction of the Difference 

 Engine. The same letter contained a proposal to Mr. Babbage, 

 on the part of Government, that he should accept the whole of 

 the drawings, together with the part of the Engine already com- 

 pleted, as well as the materials in a state of preparation. This 

 proposition he declined. 



The object of the Analytical, Engine (the drawings and 

 the experiments for which have been wholly carried on at Mr. 

 Babbage's expense, by his own draftsmen, workmen and assist- 

 ants) is to convert into numbers all the formulae of analysis, and 

 to work out the algebraical development of all formulae whose 

 laws are known. 



The present state of the Analytical Engine is as follows : — 



All the great principles on which the discovery rests have been 

 explained, and drawings of mechanical structures have been 

 made, by which each may be carried into operation. 



Simpler mechanisms, as well as more extensive principles than 

 were required for the Difference Engine, have been discovered 

 for all the elementary portions of the Analytical Engine, and 

 numerous drawings of these successive simplifications exist. 



