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 the case.
Mr. Whitmore, having had some conversation with Lord Goderich on the subject, addressed a letter, dated on the 29th of February, 1828, to Mr. Babbage, who was then at Rome, stating that
“That interview was unsatisfactory; that Lord Goderich did not like to admit that there was any understanding, at the time the 1,500 l. was advanced, that more would be given by Government.”
On Mr. Babbage’s return to England, towards the end of {73} 1828, he waited in person upon Lord Goderich, who admitted that the understanding of 1823 was not very definite. He then addressed a statement to the Duke of Wellington, as the head of the Government, explaining the previous steps in the affair; stating the reasons for his inferences from what took place at the interview with the Chancellor of the Exchequer in July, 1823; and referring his Grace for further information to Lord Goderich, to whom also he sent a copy of that statement.
The Duke of Wellington, in consequence of this application, requested the Royal Society to inquire—
“Whether the progress of the Machine confirms them in their former opinion, that it will ultimately prove adequate to the important object it was intended to attain.”