Passages from the Life of a Philosopher - Charles Babbage

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following statement was drawn up by the late Sir Harris Nicolas, G.S.M. & G., from papers and documents in my possession relating to the Difference Engine. I believe every paper I possessed at all bearing on the subject was in his hands for several months.

      For some time previous to 1822, Mr. Babbage had been engaged in contriving machinery for the execution of extensive arithmetical operations, and in devising mechanism by which the machine that made the calculations might also print the results.

      On the 3rd of July, 1822, he published a letter to Sir Humphry Davy, President of the Royal Society, containing a statement of his views on that subject; and more par­tic­u­lar­ly describing an Engine for calculating astronomical, nautical, and other Tables, by means of the “method of differences.” In that letter it is stated that a small Model, consisting of six figures, and capable of working two orders of differences, had been constructed; and that it performed its work in a sat­is­fac­tory manner.

      The concluding paragraph of that letter is as follows:—

      “Induced, by a conviction of the great utility of such Engines, to withdraw, for some time, my attention from a subject on which it has been engaged during several years, and which possesses charms of a higher order, I have now arrived at a point where success is no longer doubtful. It must, however, be attained at a very considerable expense, which would not probably be replaced, by the works it might produce, for a long period of time; and which is an undertaking I should feel unwilling to commence, as altogether foreign to my habits and pursuits.”

      The Model alluded to had been shown to a large number of Mr. Babbage’s acquaintances, and to many other persons; and copies of his letter having been given to several of his friends, it is probable that one of the copies was sent to the Treasury.

      On the 1st of April, 1823, the Lords of the Treasury referred that Letter to the Royal Society, requesting—

      “The opinion of the Royal Society on the merits and utility of this invention.”

      On the 1st of May the Royal Society reported to the Treasury, that—

      On the 21st of May these papers were ordered to be printed by the House of Commons.

      From the conversation which took place on that occasion, Mr. Babbage apprehended that such was the wish of the Government. The Chancellor of the Exchequer remarked that the Government were in general unwilling to make grants of money for any inventions, however meritorious; because, if they really possessed the merit claimed for them, the sale of the article produced would be the best, as well as largest reward of the inventor: but that the present case was an exception; it being apparent that the construction of such a Machine could not be undertaken with a view to profit from the sale of its produce; and that, as math­e­mat­i­cal Tables were peculiarly valuable for nautical purposes, it was deemed a fit object of encouragement by the Government.

      The Chancellor of the Exchequer mentioned two modes of advancing money for the construction:—either through the recommendation of a Committee of the House of Commons, or by taking a sum from the Civil Contingencies: and he observed that, as the Session of Parliament was near its termination, the latter course might, perhaps, be the most convenient.

      Mr. Babbage thinks the Chancellor of the Exchequer also made some ob­ser­va­tion, indicating that the amount of money taken from the Civil Contingencies would be smaller than that which might be had by means of a Committee of the House of Commons: and he then proposed to take 1,000 l. as a commencement from the Civil Contingencies Fund. To this Mr. Babbage replied, in words which he distinctly remembers, “Would it be too much, in the first instance, to take 1,500 l.?” The Chancellor of the Exchequer immediately answered, that 1,500 l. should be advanced.

      Mr. Babbage’s opinion at that time was, that the Engine would be completed in two, or at the most in three years; and that by having 1,500 l. in the first instance, he would be {71} enabled to advance, from his own private funds, the residue of the 3,000 l., or even 5,000 l., which he then imagined the Engine might possibly cost; so that he would not again have occasion to apply to Government until it was completed. Some ob­ser­va­tions were made by the Chancellor of the Exchequer about the mode of accounting for the money received, as well as about its expenditure; but it seemed to be admitted that it was not possible to prescribe any very definite system, and that much must be left to Mr. Babbage’s own judgment.

      Very unfortunately, no Minute of that conversation was made at the time, nor was any sufficiently distinct understanding between the parties arrived at. Mr. Babbage’s conviction was, that whatever might be the labour and difficulty of the undertaking, the Engine itself would, of course, become the property of the Government, which had paid for its construction.

      Soon after this interview with the Chancellor of the Exchequer, a letter was sent from the Treasury to the Royal Society, informing that body that the Lords of the Treasury

      “Had directed the issue of 1,500 l. to Mr. Babbage, to enable him to bring his invention to perfection, in the manner recommended.”

      These latter words, “in the manner recommended,” can only refer to the previous recommendation of the Royal Society; but it does not appear, from the Report of the Royal Society, that any plan, terms, or conditions had been pointed out by that body.

      Towards the end of July, 1823, Mr. Babbage took measures for the construction of the present Difference Engine,* and it was regularly proceeded with for four years. {72}

      * NOTE.—It will be convenient to distinguish between—

       1. The small Model of the original or Difference Engine.

       2. The Difference Engine itself, belonging to the Government, a part only of which has been put together.

       3. The designs for another Engine, which in this Statement is called the Analytical Engine.

      In October, 1827, the expense incurred had amounted to 3,475 l.; and Mr. Babbage having suffered severe domestic affliction, and being in a very ill state of health, was recommended by his medical advisers to travel on the Continent. He left, however, sufficient drawings to enable the work to be continued, and gave an order to his own banker to advance 1,000 l. during his absence: he also received, from time to time, drawings and inquiries relating to the mechanism, and returned in­struc­tions to the engineer who was constructing it.

      As it now appeared probable that the expense would much exceed what Mr. Babbage had originally anticipated, he thought it desirable to inform the Government of that fact, and to procure a further grant. As a preliminary step, he wrote from Italy to his brother-in-law, Mr. Wolryche Whitmore, to request that he would see Lord Goderich upon the subject of the interview in July, 1823; but it is probable that he did not sufficiently inform Mr. Whitmore of all the circumstances of

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