Longitude, ladies and computers

07 Oct 2011

Today is Ada Lovelace Day, which aims "to raise the profile of women in science, technology, engineering and maths by encouraging people around the world to talk about the women whose work they admire". It is the excuse to devote science and history of science blog posts to women of the past, as well as to recall those who have given more direct inspiration to the writer. Sharon Howard has collected many of today's posts on Tumblr.

Ada, Byron's daughter and Countess of Lovelace, has a tenuous link to our theme in as much as she is credited with writing the first 'computer programme' for Charles Babbage's Analytical engine, which, like his Difference engine, aimed to automate the production of numerical tables, reducing human error. In particular, he was thinking of astronomical tables produced for longitude determination - the Nautical Almanac that had attracted so much recent criticism. It was this that caught the interest of government.

I'll admit, though, that I've always found Ada Lovelace a slightly strange symbol for the achievements of women in science. While her mathematics tutor, Augustus De Morgan suggested, to her mother, that she might have the potential to be "an original mathematical investigator, perhaps of first-rate eminence", there is some doubt as to how much she actually achived (see Thony Christie on this point). It is likely that Babbage himself over-emphasised her role as a PR exercise for his machine, and Lovelace's youth, attractiveness, fame and wealth may have been as important as her mathematical abilties. While she played a role, as many other women, in explaining scientific work to a wider audience, the programming idea seems to have been outlined to her by Babbage, who was inspired by the punchcards used for the Jacquard Loom.

Another irony is that, had Babbage's Difference and Analytical engines come to fruition, they could have had the effect of actually reducing the vanishingly small number of women who made a living from scientific work in the 19th century. The aim was to replace the human computer, an area in which women were, at times, accepted, most famously in Harvard Observatory as 'Pickering's Harem'.

It is a female computer, then, rather than the putative female computer programmer, that is the real subject of this post. She is one of only a handful of women to have received money directly from the Board of Longitude, and only one of two to have done so in her own right, for the others were widows - of Tobias Mayer and Charles Mason - who were paid for their husband's work and tables. She was Mary Edwards who has, fortunately, been researched and rescued for posterity in an article (£) by Mary Croarken (who will be speaking at Greenwich on Saturday 15 October as part of the Maskelyne Symposium).

Edwards did piecemeal work, from her home in Shropshire, doing computations for the Nautical Almanac. She might well have been lost to history, for the accounts list her husband, John Edwards,  a clergyman, as receiving payment for work on 6 months-worth of each alamanac from 1773 to 1784.  It was, however, Mary who had done most of the calcuations, thus doubling the family income. This was only revealed after her husband's death in 1784, when Edwards asked Nevil Maskelyne if she could continue work in order to support herself and her daughters. He agreed, and the accounts move seamlessly from 'John Edwards' to 'Mary Edwards'. 

While the work was not mathematically advanced, and it was certainly tedious, Croarken notes that the underlying principles had to be understood: "Mary Edwards had both knowledge and experience and, by the early 19th century, is known to have played a role in teaching younger computers". In addition, she was accurate and her rate of errors was "unusually low". Working under her own name she also increased her workload, computing 12 months of each year's Almanac, half of the whole computing power needed (each month is calculated twice and compared). The other half of the work was undertaken by three or four other individuals.

Edwards continued her work, bringing her daughters into the family trade, into the new century. There were no problems, although also no advancement, until Maskelyne's death in 1811. On John Pond's taking over the editing of the Nautical Almanac, she suddenly found her work being reduced, leading her to petition the Board and Parliament. Croarken writes that "The Board acknowledged that she had been a good and faithful worker for many years and allowed her to compute 8 months of the Nautical Almanac while being paid for almost 12 months' work. Although this did largely relieve her financial difficulties, it did not reinstate her to the more prestigious position of Nautical Almanac comparer", which she had briefly enjoyed over the last few years.

Mary Edwards died in 1815, her daughter Eliza continuing as a computer until 1832, when the work of the Nautical Alamanc was centralised, and computing ceased to be the cottage industry in which the Edwards had specialised. As in other fields in the 19th century, such women had their earning power removed. It was not reinstated until the very end of the century, when the idea of women leaving home to receive training or undertake work became a (rare) possibility.