construction. The necessary science and skill specially acquired in executing such works must also, as experience is gained, suggest deviations from, and improvements in, the original plan of those works; and the adoption or rejection of such changes, especially under circumstances similar to those in which I was placed, often involves questions of the greatest difficulty and anxiety.
From whatever cause, however, the delays and expenses arose, the result was that the Government was discouraged, and declined to proceed further with the work.
Mr. Goulburn's letter, intimating this decision to me, in 1842, will be found in the accompanying printed Statement. And that the impediments to the completion of the engine, described by the Royal Society, were those which influenced the Government in the determination they came to, I infer from the reason assigned by Mr. Goulburn for its discontinuance, viz., "the expense which would be necessary in order to render it either satisfactory to yourself or generally useful." I readily admit that the work could not have been rendered satisfactory to myself unless I was free to introduce every improvement which experience and thought could suggest. But that even with this additional source of expense, its general usefulness would have been impaired, I cannot assent to, for I believe, in the words of the Report I have already quoted, the "immense advantage of accurate Numerical Tables in all matters of calculation, especially in those which relate to Astronomy and Navigation, cannot, within any reasonable limits, be over-estimated." As to the expense actually incurred upon the first Difference Engine, that of the Government was about 17,000l. On my own part, and out of my own private resources, I have sacrificed upon this and other works of science upwards of 20,000l.
