Menabrea’s account of Babbage’s engine was originally written in French. Luigi Federico Menabrea, an Italian engineer and mathematician, published his description after hearing Babbage lecture about the Analytical Engine in Turin. Ada Lovelace later translated that French account into English.
Menabrea’s article appeared in 1842 in the Swiss journal Bibliothèque universelle de Genève. Its subject was Babbage’s proposed Analytical Engine, a machine intended to perform a sequence of operations under the direction of punched cards. The article explained the design and significance of the machine to readers who had not attended Babbage’s lecture.
Lovelace’s English translation was published in 1843 in Taylor’s Scientific Memoirs, accompanied by seven substantial notes of her own. Those notes greatly expanded the original text and included her celebrated discussion of an algorithm for calculating Bernoulli numbers. The language sequence is therefore easy to reverse: Menabrea wrote in French, while Lovelace translated the work into English.