The only known photographs of mathematician and computing pioneer Ada Lovelace have been acquired by the National Portrait Gallery just before they were expected to be sold to a private buyer.

(c) Bonhams

Ada Lovelace was an English mathematician and writer, and is chiefly known for her work on Charles Babbage’s proposed mechanical general-purpose computer, the Analytical Engine. She was the first person to realise that the machine had applications beyond pure calculation, and is widely recognised for her contributions to early computing and mathematics.

There are many paintings of her, but only three known photographs, and all three were recently put up for sale by Bonhams in London with an estimate of £80,000 to £120,000.

However, the photographs were withdrawn from sale just before auction, and it’s now been confirmed that the National Portrait Gallery bought them privately.

Louise Williamson, Tax and Heritage Consultant in Bonhams’ Valuations department, commented: “It was wonderful to be involved in this important acquisition of the only known photographs of Ada Lovelace by the National Portrait Gallery via private treaty sale. Private Treaty Sales allow qualifying museums to acquire pre-eminent works of art or other objects from private owners for a ‘special price’, which reflects a tax incentive that is shared between the seller and the acquiring institution. They are an increasingly important way for museums to expand their collections, and it was pleasure to work with Matthew Haley to facilitate the sale through Bonhams.”

The acquisition was supported by Tim Lindholm and Lucy Gaylord Lindholm through the American Friends of the National Portrait Gallery.

Two of the daguerreotypes are by Claudet and were taken around the critical year 1843 when Lovelace published her celebrated paper on Babbage’s Analytical Engine. In it she described in table form the use of punched cards to calculate Bernoulli numbers – often dubbed ‘the first computer programme’. Her comment that ‘The Analytical Engine has no pretension whatever to originate anything,’ has also been said to anticipate debates on artificial intelligence.

The photographer Antoine Claudet (1797-1867) learned photography from Louis Daguerre in the late 1830s, before establishing his first daguerreotype studio in London in 1841 behind St Martin-in the-Fields church. Subsequent studios were at Regent’s Park and finally Regent Street. Claudet photographed several other scientists including Babbage, Faraday, and Sir Charles Wheatstone, and it is likely that one of them recommended him to their friend Lovelace.

The third daguerreotype is by an unknown photographer and reproduces a painting by Henry Wyndham Phillips (1820-1868). His father Thomas produced the iconic portrait of Lovelace’s father Byron in Albanian dress. Lovelace sat for Henry Phillips in August 1852, and in the intervening decade since the Claudet photographs, her already fragile health had worsened. She was suffering horrifically from the uterine cancer that would end her life that November. Seated at a piano, she is gaunt and in a laudanum-induced daze – her husband William remarking in his diary that “the suffering was so great that she could scarce avoid crying out”, yet “she sat at the piano some little time so that the artist could portray her hands”.