Nineteenth-century scientific translation did not have to be precise. Mary Somerville, as Laplace cordially acknowledged, had gone beyond him in her interpretation of his own major work. Ada, translating Menabrea, was more cautious. Fluent herself in French, she produced a clear English version in which one slip (too much has since been made of a misread ‘cas’ for the ‘cos’ of a cosine) was notably overlooked by both Wheatstone and even Babbage himself. Those two brilliant men saw no flaw; what they did approvingly note was the clarity of Ada’s single footnoted adjustment to Menabrea’s text.*
It was Babbage, according to his own entertaining (but frequently unreliable) autobiography, who now proposed that Ada should put to further use her exceptional knowledge of his cherished project. Menabrea had described the components of the machine based upon what he had been shown in Turin, engraved on wooden blocks and also in stereotyped plans, drawn by Babbage’s son. The Italian mathematician and engineer explained how these components would be deployed (with particular attention to the innovative use of instruction cards carrying – as Menabrea was the first to note in print – the equivalent of algebraic formulae). He also observed the considerable simplification of time-consuming intellectual labour that would result from the Engine’s operations. ‘[W]ho can foresee the consequences of such an invention?’ Menabrea asked in his conclusion. Ada’s challenge was to answer that question, above all by showing that Babbage’s embryonic Engine was more than just an improved calculating machine. The bounds of ‘mere arithmetic’ had now been overstepped, Ada would write in the ‘Notes’ that formed her extended commentary on Menabrea’s report:
the Analytical Engine does not occupy common ground with mere ‘calculating machines’. It holds a position wholly its own; and the considerations it suggests are most interesting in their nature . . .
A new, a vast, and a powerful language is developed for the future use of analysis, in which to wield its truths so that these may become of more speedy and accurate practical application for the purposes of mankind than the means hitherto in our possession have rendered possible.*
Reading those visionary words today, it’s hard to accept that they were written a hundred years before the birth of electronic computers as we know them today.
Composing her notes to Menabrea’s article over the early spring and summer of 1843, Ada Lovelace aimed to describe and demonstrate the importance of Babbage’s invention in clear language. As the best popular science writing still does, she used visual analogies to illustrate her points.
As a mathematician, Ada had reached a level high enough to describe Babbage’s machine and discuss it with the inventor. But it is not as a mathematician that we respect her. What is remarkable about Ada Lovelace’s published ‘Notes’ – the only completed scientific writing that she appears to have produced – is the evidence they provide that, through the combination of an intuitive intelligence and her awareness of the years of discussions and planning that lay behind the unbuilt Engine, a young Victorian woman glimpsed its significance for a world that was not yet ready either for it or for her.
The birth of the computer did not depend solely upon Lady Lovelace, but she unquestionably belongs to the history of that genesis. Armed with hindsight, we see how close Ada came to predicting not only the arrival of the universal computer, but the potential of technology to transform the way we function. Her perception would prove to be as suggestive and retrospectively influential as Mary Shelley’s dark vision, in 1816 (after a memorable night of storytelling in the company of Ada’s exiled father, out in a rainswept villa overlooking Lake Geneva), of the birth of bio-engineering.
Neither woman changed the world in which they lived. Uniquely, both Lovelace and Shelley foresaw the role that technology might have to play in transforming a world they never knew.
Armed with a six-month deadline (Richard Taylor required copy by the end of the summer of 1843), Ada set to work on writing up the ‘Notes’ soon after Hester’s February wedding. Reading through her translation of Menabrea, Ada identified seven points at which to add a series of her own notes (A to G) correcting or augmenting the Italian engineer’s skilful exposition. In note A – by which Babbage was so delighted that he implored her not to change a single word – Ada used Menabrea’s account of the Difference Engine’s limitations as a stepping stone to her own perception of what the unbuilt Analytical Engine might potentially be enabled to achieve.
Among the longest of Ada’s seven commentaries (it covers ten printed pages), Note A introduced the possibility that the Engine would act upon other things besides number. Music, a subject close to Ada’s heart, offered a striking example.
Supposing, for instance, that the fundamental relations of pitched sounds to the science of harmony and of musical composition were susceptible of such expression and adaptations, the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent. [694]
How would the engine succeed in doing this? Menabrea had explained the method of using numerous punched cards that Babbage had adapted from Jacquard’s celebrated loom. Ada, while thoughtfully advising readers in a later note (C), to visit one of the two London Science Halls at which a Jacquard loom could be observed in action, used the analogy of mechanised picture-weaving to create one of her own most striking images, while pointing to the technical advance upon Babbage’s earlier machine. The Difference Engine used cards only to print off the results of its (purely arithmetical) calculations:
The distinctive characteristic of the Analytical Engine, and that which has rendered it possible to endow mechanism with such extensive faculties as bid fair to make this engine the executive right-hand of abstract algebra, is the introduction into it of the principle which Jacquard devised for regulating, by means of punched
