Babbage, Charles (1791 – 1871)

Babbage acquiesces to a showing of  his Calculating engine, one of the world’s first computers

An excellent and desirable autograph letter signed by Charles Babbage, ‘C. Babbage’, May 30th 1834. The polymath writes to Dunbar James Douglas, 6th Earl of Selkirk (1809-1885), inviting him to a lecture.

In full: ‘Having learned from the Duke of Somerset that you have a great desire to see the Calculating engine I am happy to offer you an opportunity which will I hope be interesting. Lord and Lady Lansdowne and a very small party are coming to my house tomorrow evening at half past nine and Dr. [Dionysius] Lardner has sent his drawings and will give us a popular explanation of it. If Lady Selkirk and your sister will do me the honour of accompanying you, I shall have much pleasure in seeing them at my house.’ In very fine condition.

An extraordinary memento from the early history of the computer; letters by Babbage that reference the early iterations of the computer are rare and sought-after. This letter also represents a last-ditch attempt by Babbage to drum up aristocratic support for his Difference Engine No. 1, with the project months away from its collapse (the Analytical Engine being the model that followed). The manufacturing engineer Joseph Clement had ceased work on the project in March 1833 following a financial dispute. He had, however, succeeded by 1832 in producing a fully functioning demonstration piece representing about one-seventh of the whole machine, which as the first known automatic calculator ranks among the most celebrated icons in the prehistory of computing. Babbage himself published little on the design of either his difference or analytical engines, but he received prominent support from the Irish scientific writer Dionysius Lardner who, in 1834, delivered a series of lectures on the difference engine and contributed a lengthy article on the subject, titled ‘Babbage’s Calculating Engine’ to The Edinburgh Review.