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96/203/2 Letters (2), from Countess Ada Lovelace to Charles Babbage, paper, England, 1838-1847. Click to enlarge.

Letters from Ada Lovelace to Charles Babbage

These letters are from Countess Ada Lovelace to Charles Babbage, an English mathematician, inventor, philosopher, and reformer who, more than 100 years before the computer age, designed a general-purpose mechanical calculating machine that anticipated the principles and structure of the digital computer. In 1823 Babbage started working on his Difference Engine No 1, a fully automatic machine that was designed to calculate and print the tables used in the burgeoning fields of science, …


Object No.


Object Statement

Letters (2), from Countess Ada Lovelace to Charles Babbage, paper, England, 1838-1847

Physical Description

Two letters from Ada Lovelace, adressed to Charles Babbage, handwritten and folded into a self made envelope. The first is watermarked 1838 and attributed in later hand to 1840/41. It asks for an acquaintance's address and is addressed 'Dear Mr Babbage' and signed 'A A Lovelace'. The letter can be folded to create a small envelope, with two separate halves of the sticker or seal featured in orange with gold trim and a gold crown above 'Ada'.

The second letter dated 1847 is addressed more familiarly as 'Dear Babbage' and signed 'A L'. This letter refers to the delivery of Mr Babbage's coat and an impending visit to London. This letter can also be folded to form an envelope, however no evidence of a seal.



185 mm


225 mm



The letters are part of an acquisition that includes a specimen section of Charles Babbage's Difference Engine No 1. This calculating device was designed by Charles Babbage between 1822 and 1833, after which the project was abandoned. The mechanism demonstrated in the specimen was probably designed in the early stages. He designed the engine to automatically calculate and print mathematical tables, used at the time for complex calculations relating to navigation, surveying, astronomy, annuities etc. The engine was designed to use the Method of Finite Differences to generate successive values of a polynomial function. New tools and manufacturing techniques were developed to make it. Most of the parts were eventually made, but the machine was never assembled.

While Babbage was working on the Difference Engine he started to think about a machine that would be more versatile. When the Difference engine project was abandoned he went on to design most of the Analytical Engine, which was in effect a programmable mechanical computer with the same architecture as a modern electronic computer. Certain innovations he developed for the Analytical Engine were later incorporated into a more efficient difference engine, Difference Engine No2.

The parts for the Difference Engine were made by Joseph Clement who was a highly skilled toolmaker and tradesman.

The unassembled parts of the Difference Engine were inherited by Henry Provost Babbage after the death of his father in 1871. In 1979 he assembled 5, 6 or 7 specimen pieces (accounts in the writings of Henry differ). These pieces were to demonstrate the addition and carry mechanism of the engine. One he gave to Cambridge, one to University College, London (now at the Science Museum), one to Harvard College in America, one to Charles Whitmore Babbage, Henry's nephew who took it to New Zealand. One, two or three others are unaccounted for.



These letters were purchased by the museum at auction along with a portion of Babbage's Difference Engine No 1.

None of Babbage's machines was ever completed. But in 1832 he assembled a working portion to demonstate its function to the British Parliament in what was was probably a last attempt to gain continued funding. This portion, now at the Science Museum , was capable of generating, but not printing, tables for 2nd degree polynomials. Babbage did generate tables for some functions. The descendants offered the Engine and related material for auction through Christie's of London on 4 October 1995


Credit Line

Purchased 1996

Acquisition Date

5 June 1996

Cite this Object


Letters from Ada Lovelace to Charles Babbage 2021, Museum of Applied Arts & Sciences, accessed 26 June 2022, <>


{{cite web |url= |title=Letters from Ada Lovelace to Charles Babbage |author=Museum of Applied Arts & Sciences |access-date=26 June 2022 |publisher=Museum of Applied Arts & Sciences, Australia}}