Classics in the History of Psychology

An internet resource developed by
Christopher D. Green
York University, Toronto, Ontario

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Introduction to Ada Lovelace's Translation of, and Notes to, Luigi F. Menabrea's
"Sketch of the analytical engine invented by Charles Babbage, Esq." (1842/1843)

Christopher D. Green
York University

© 2000 Christopher D. Green
All rights reserved.

First posted February 2000.
Revised December 2000.
Revised April 2001.


1. Augusta Ada Byron was born in December of 1815 to the famous poet George Gordon, Lord Byron and his wife, Anne Isabella Milbanke, Lady Byron, less than a year after their marriage. Lord and Lady Byron separated little more than a month after her birth. The separation aroused a great deal of public scandal in its day. Lord Byron left England permanently three months later. He died of disease in Greece eight years later, in April of 1824.

2. Although Ada, as she was called, was allowed little information about her father, his presence was allowed to "haunt" the family in a number of ways. For instance, a nearly life-size portrait of Byron hung in the Milbanke home (in which Ada lived during part of her childhood), but was shrouded with a green curtain so that it could not be viewed. Lady Byron was careful never to speak ill of her husband in public, often praising his "genius," but she seems to have simultaneously conducted an extensive "whisper campaign" against him among her circle of friends, intimating among other things that he had engaged in a sexual affair with his half-sister, Augusta Leigh, and that one of Augusta's daughters, Elizabeth Medora Leigh was a product of that alleged liaison. It is unclear whether he actually had such an affair. Literary historians have debated the issue for over a century. It is almost certain that Medora was not his daughter. Lady Byron's evidence, even on her own account, was merely suggestive. Nevertheless, the obvious, if implied, threat was that she would make public this "information" were he ever to return to England, or try to claim custody of his daughter.

3. Determined that her daughter should not inherit her husband's alleged perversities, whether real or imagined, Lady Byron raised Ada according to a strict educational regime. The study of mathematics was especially important to Lady Byron, who had studied mathematics herself as a girl, and she was intent on her daughter learning the subject as well. When Ada was 13, her mother called upon her own childhood tutor, Dr. William Frend, as well as a Dr. William King, to teach Ada basic science and math. The studies were interrupted when Ada contracted a serious case of the measles in 1829. The disease left her an invalid for a time, and she did not fully recovered for almost three years. Although her studies resumed during this time, they were often interrupted by recurring bouts of illness. By 1833, at the age of 17, she was well enough to "come out" in London society, and it was during the parties of this season that she first met Charles Babbage (1791-1871).

4. Babbage had graduated from Cambridge in 1814, and first made a name for himself in 1816 by publishing with his friends, John Herschel and George Peacock, a translation of a French text on calculus. The venture was intended to promote the adoption by British mathematicians of the Leibnizian notation for calculus, which was then standard almost everywhere but Britain (where the old Newtonian notation held British mathematics decades behind the Continent). He was elected a member of the Royal Society the same year at the age of only 24. By 1820, apparently frustrated with the errors he found in the published mathematical tables of the day, Babbage developed a design for a machine that would calculate and print them flawlessly. He called the machine the "Difference Engine" because it depended on a procedure known as the "method of differences" for its calculations. He worked up a small model of the machine by 1822, which he presented to the Royal Society in support of an application for funding. After almost a year's delay the Society recommended to the Government that Babbage be granted 1500 to build a full-scale machine. This was followed by more and still more Government money. After more than a decade of work, 17,000 in public funds had been spent on the project without a fully working engine having yet been produced. By 1833, however, Babbage had come up idea for a radically new machine, one that could calculate and print the result of any function at all, not just those reducible to the method of differences. In 1836 he hit upon the idea that the operation of this new machine could be controlled by having it "read" instructions coded into punched cards, like those used in the automatic loom that had been built by Joseph-Marie Jacquard in France in 1801. He called the new machine the "Analytical Engine." The process of attempting to obtain grant money began again, but at least in part because of the fiasco involving the Difference Engine, no one was willing to commit funds.

5. Returning to Ada's story, she apparently tried to run away with a young male tutor in late 1833 or early 1834. As a result, in 1834, when Ada was 18, Dr. King was engaged once again, but this time to teach her mathematics more as an exercise in mental discipline than as an academic pursuit in its own right. She called for a very strong "prescription" for herself: Euclidean geometry, followed, she said, by "Arithmetic & Algebra," eventually leading to the study of "Astronomy, Optics, etc." Ada also enlisted the mathematical assistance of a notable neighbor and family friend, Mary Somerville (1780-1872), the leading English woman scientist of her day. Although Ada and Somerville would often attend together both London lectures and the fashionable evening parties that Babbage held -- at which he would demonstrate the small model of his Difference Engine and various other mechanical contrivances -- a long course of mathematical and scientific studies was not to be. Over the summer of 1835, she met and married William Lord King (not related to her childhood math tutor), an old college chum of Mary Somerville's son. Ada tried to resume her mathematical studies in the fall of 1835, but she was soon pregnant with her first child, Byron, who was born in May 1836. A daughter, Anne Isabella, was born in September 1837. Victoria, crowned Queen 28 June 1838, raised Ada's husband to Earl of Lovelace, and she to the Countess of Lovelace. Ada was soon pregnant again, and her third and final child, Ralph, was born in July of 1839. In November 1839, now nearly 25 years old, she wrote to Babbage, asking if he knew someone who could tutor her in mathematics. In June 1840 she finally resumed her mathematical studies in earnest, under the tutelage of Augustus DeMorgan, a man who would become one of the greatest English logicians of the 19th century. It was not until this time that Ada took up the study of calculus, about which DeMorgan happened to be writing a text at the time.

6. In August of the same year, Babbage, who was never able to earn the recognition in England he would have liked, was invited to give a series of lectures on the Analytical Engine in Turin, Italy. He had hoped that the prominent Italian scientist Baron Giovanni Plana (1781-1864) would write an account of the lectures, but the job was given over to a then-unknown military engineer, Luigi Menabrea (1809-1896), who would later become a general in Garibaldi's war to unite the Italian states, and eventually Prime Minister of the newly-unified Italy. Babbage seems to have assisted Menabrea, and the article was published in French, in the Bibliothèque Universelle de Genève in October 1842.

7. Coincident with Ada's study of basic differential calculus was a change in her attitude about herself. Whereas before she had been relatively modest about her abilities and deferential with her teachers, beginning in January 1841 her letters began to claim special intellectual talents. Of course, many people feel that they have come to see the world in a new and powerful way upon learning calculus--its invention was one of history's great scientific breakthroughs--but Ada describes herself in ways that are self-aggrandizing, to say the least, given the state of her learning and accomplishment; sometimes they border on the delusional. In a January 11 letter to her mother she wrote of the "vast change that 6 months have made in me." A few days later, on January 15, she wrote to her friend Woronzow Greig that "Heaven has allotted me some intellectual-moral mission to perform." On February 6 she wrote, again to her mother, that she felt herself to be "pre-eminently a discoverer of the hidden realities of nature;" this by virtue of her special intellectual talents. First, owing to what she called "a peculiarity in [her] nervous system," she claimed to have "perceptions of some things, which no one else has; or at least very few, if any. This faculty may be designated in me as a singular tact, or some might say an intuitive perception of hidden things; -- that is of things hidden from eyes, ears & the ordinary senses." Second, she claimed "immense reasoning faculties;" and, third, what she called her:

concentrative faculty, by which I mean the power not only of throwing my whole energy & existence into whatever I choose, but also bringing to bear on any one subject or idea, a vast apparatus from all sorts of apparently irrelevant & extraneous sources. I can throw rays from every quarter of the universe into one vast focus.

8. That she believed these talents to go beyond keen observation and mathematical reasoning is made clear in a March 1841 letter; a response to the news that DeMorgan's father-in-law, and her own one-time tutor, William Frend, had died. She wrote to his bereaved daughter, and long-time friend, Sophia DeMorgan:

I always feel in a manner as if I had died, & as if I can conceive & know something of what the change is. That there is some remarkable tact & intuition about me I have not a doubt...I have sometimes used the expression that I have a little bit of another sense."

9. One is rightly wary of diagnosing psychopathology from the distance of over 150 years on the basis of a few letters, but it is incontrovertible that Ada's opinion of her own intellectual powers and destiny was well out of proportion to her relatively elementary accomplishments at this time.

10. There was not much time for her to reflect on her newly "discovered" talents, however. The ongoing Medora Leigh "crisis" took her to France in April 1841. It was not until July that she was able to begin her studies again, moving at long last on to the study of integral calculus. She seems to have stopped her mathematical studies again before the year 1841 was out, however, shifting her attention to music and theater. By April of 1842 she described these as her "real and natural genius." Her plan at this time seems to have been to abandon mathematics in favor of the arts. Ada's new plan of study was undertaken over the objections of her mother and husband who, uncharacteristically for the time, encouraged her to continue her work on math and science. A letter to DeMorgan in August 1842 shows that she had by this time taken up mathematics once again, if somewhat half-heartedly.

11. In February of 1843, Charles Wheatstone -- a family friend, and co-inventor of the telegraph -- suggested that Ada begin work on an English translation of Menabrea's account of Babbage's Turin presentations for Richard Taylor's Scientific Memoirs, a journal that specialized in English translations of foreign scientific papers, and reports from foreign scientific meetings. Babbage's version of the story, written some twenty years after the event, was that when Ada presented him with the completed translation, the preparation of which he was not previously aware, he asked why she had not written, instead, an original article of her own. She is said to have replied that the idea had never occurred to her, and he reports that he then suggested that she write some notes explicating parts that Menabrea had left vague or that had been since superseded by new developments. She worked closely with Babbage on the Notes throughout the spring and summer of 1843. They would ultimately run to more than twice the length of Menabrea's article. Dozens of letters and drafts flew back and forth between Ada and Babbage, and personal meetings were frequent. The question of how much of them, in the final analysis, are original to Ada and how much are really Babbage's ideas communicated through her is a subject of continuing controversy. The Notes were completed by August 1843, and they appeared as the last article of Volume 3 of Taylor's Scientific Memoirs in September 1843.

12. As always, Ada was highly impressed with her own work, and was not shy about detailing its, and her own, virtues to Babbage: "I do not believe," she wrote, "that my father was (or ever could have been) such a Poet as I shall be an Analyst (& Metaphysician)..." And again, about the same time:

I cannot refrain from expressing my amazement at my own child [her Notes]. The pithy and vigorous nature of the style seem to me to be most striking; and there is at times a half-satirical & humorous dryness, which would I suspect make me a most formidable reviewer. I am quite thunder-stuck at the power of the writing. It is especially unlike a woman's style surely, but neither can I compare it with any man's exactly.

13. And later in the same letter:

To say the truth, I am rather amazed at [the Notes]; & cannot help being struck quite malgré moi, with the really masterly nature of the style, & its Superiority to that of [Menabrea's] Memoir itself.

14. As her work on the Notes wound down, she began to make plans for other scientific work. Interestingly, however, they almost all seemed to involve reviewing or translating someone else's work, rather than conducting original research of her own, whether mathematical or scientific.

15. As the time of publication neared, Ada's attitude toward Babbage began to change. She became testy, and eventually downright imperious. On July 19 she admonished Babbage for having made corrections to an out-of-date draft. On July 22 she wrote somewhat patronizingly (to a man nearly 25 years her senior):

I must now explain one or two things. I am much annoyed at your having altered my Note. You know I am always willing to make any required alterations myself, but that I cannot endure another person to meddle with my sentences.

16. On July 28, unable to find a portion of one Note, she wrote him accusingly, "I have always fancied you were a little harum-scarum & inaccurate now & then about the exact order & arrangement of sheets, pages, & paragraphs, &c.... I should be decidedly inclined to swear at you." Then on July 30 she declared, "I do not think you possess half my forethought & power of foreseeing all possible contingencies....How very careless of you to forget that Note, & how much waiting on & service you owe me, to compensate."

17. In early August, the little skirmishes with Babbage erupted into a full-blown dispute. Babbage wanted to attach a preface to the translation and Notes, explaining the history of his inability to obtain additional government funding for the Engine. William Francis, Richard Taylor's assistant editor, said that such a piece would be unusual for the journal, and that he could not approve it in Taylor's absence (who was at that time out of the country). If Babbage insisted on trying to add it, they could hold the translation and Notes until Taylor's return, but that would mean delaying their publication. Babbage asked Ada to withdraw the translation and Notes. Ada refused, claiming that to do so would be "dishonorable & unjustifiable." On August 14 she wrote to him a long litigious letter, in which she went so far as to make the continuance of their collaboration contingent on his turning over the management of his work entirely to her, while promising himself to work on nothing but the machine until it was complete. As if determined to add insult to injury, she went on to explain to him that, "My own uncompromising principle is to endeavour to love truth & God before fame and glory or even just appreciation....Yours is to love truth & God (yes, deeply & constantly); but to love fame, glory, honours yet more." In a final apotheosis of arrogance she proclaimed that, "Thro' my present relations with man, I am doubtless to become fit for relations with another order hereafter; perhaps directly with the great Power Himself."

18. What Babbage's exact reply was to this demand that he surrender control of work, and much of his life, to this self-proclaimed future interpreter of the Almighty, we do not know. Ada and Babbage met a day or two later. After the meeting Babbage wrote at the top of the letter containing her demands: "saw AAL this morning and refused all the conditions." The details of his refusal would be fascinating to know, however, for only a week later Ada wrote to her mother, "Babbage and I are I think more friends than ever." On September 9 Babbage wrote to her, calling her his "much admired Interpreter," and the "Enchantress of Numbers." On September 10 she wrote to back: "You are a brave man to give yourself wholly up to Fairy-Guidance!" He seems to have led her to believe that he had accepted her conditions.

19. After the initial excitement about the Notes, Ada attempted to get down to other scientific projects, but her efforts came to naught. There had also been a plan to "define & classify all that is to be legitimately included under the term discovery," but it seems never to have gotten beyond a few casual comments. Wheatstone seems to have developed a plan to have Ada serve as a scientific tutor-lobbyist to Prince Albert, but that too went nowhere. She had also once talked about conducting experiments relating the electrical activity of the nervous system to mesmerism, of which Lady Byron was a devotee. In October of 1844 she wrote to the famed physicist Michael Faraday (1791-1867), asking him to assist her in conducting replications of all his experiments, by way of teaching her experimental methods. He replied that his health would not allow it. Still in need of a scientific tutor, she wrote to one Andrew Crosse, a rather elderly gentleman-scientist of mixed reputation who had conducted some research on electricity, but had become embroiled in a controversy over spontaneous generation. He agreed to help her. Although she enjoyed long visits at the Crosse estate during which extensive discussions about science were held, it is unclear whether she received any real training from Crosse. The upshot is that she never again approached the level of accomplishment she had achieved in the Notes to the Menabrea article. In the late 1840s Ada became involved in a horse-betting consortium that included Andrew Crosse's son, John, among others. She did very badly, twice having to resort to pawning the family jewels in order to cover her losses. Contrary to popular claims, however, there is no evidence that Babbage was part of the group, or that the bets were based on some sort of mathematical system that Babbage and Ada had cooked up as a way of raising money for the Analytical Engine. In June of 1851 Ada suffered a series of severe hemorrhages. Although it took a long time, she was eventually diagnosed with advanced uterine cancer. After a sometimes agonizing year and a half she died, two weeks before what would have been her 37th birthday.

20. Two years later, in 1854, a Swede named George Scheutz finally constructed a working Difference Engine, though not one as large as that Babbage had originally planned. Babbage himself died in 1871, the Analytical Engine still not built. His son, Henry, took over the project, but was not able to finish it either.

21. Ada's work lay virtually unknown for almost a century. There are brief mentions of her in Douglas Hartree's (1949) book Calculating Instruments and Machines, and in Alan Turing's (1950) "Computing machinery and intelligence," the latter of which is probably the most influential article in the history of artificial intelligence. It was really Bertram Vivian Bowden, however, who may be said to have "rediscovered" Ada. Her image appeared in the frontispiece of his edited volume, Faster Than Thought; A Symposium on Digital Computing Machines, and its introduction (Bowden 1953) which presented the first account of Ada's work, and contained the first reprinting of her translation and Notes in almost 70 years. Unfortunately, the many errors he made, based on his incomplete study of the documents of her life, rattle around in the many cursory accounts of her life and work to the present day. To begin with, Bowden got her full name wrong: she was Augusta Ada, named after her aunt Augusta Leigh, not "Ada Augusta." His probable source for this error was the biography of Ralph Lovelace, Ada's younger son, written by his wife, Mary Lovelace (1920, p. 165). In addition Bowden revived the story, also first made by Mary Lovelace that Ada "and Babbage eventually turned their attention to developing an infallible system for backing horses." Bowden's entire account runs to less than 3 pages. Although he credits Ada with writing "what we should now call a programme for computing the Bernoulli numbers," he does not explicitly claim her to have been the first to have written such a program. In the end, her accomplishment is described modestly as having "made it possible for us to appreciate Babbage's genius."

22. Philip and Emily Morrison (1961) give a brief account of Ada in the introduction to their book, Charles Babbage and his Calculating Machines, but one that seems to be drawn largely from Bowden's. By far the most detailed account of Ada's life and work during the 1960s was contained in Maboth Moseley's (1964) biography of Babbage. It is a problematic work, however, because in spite of its appearance of complete legitimacy -- Bowden himself wrote the Foreword -- it is highly unreliable; so much so that one of Ada's biographers has described it as being "almost perversely inaccurate, distorted and fabricated..." Ultimately, it was not an historian of computing, but rather a Byron scholar, Doris Langley Moore, who wrote the first full biography of Ada (Moore 1977). Moore was the first person to have full access to, and to make a full study of, the Lovelace Papers. As a consequence, her biography is a very detailed one. Because, however, it was written by one whose main interest was Lord Byron, and by one who, by her own admission, knew little about mathematics or computers, it sheds little light on the subject that makes Ada's life most worth writing about. The two chapters of Moore's biography corresponding to the period during which Ada learned calculus and wrote the translation and Notes are, instead, dominated by an unstinting account of the Medora Leigh affair.

23. In 1980 the U.S. Department of Defense christened their new standard computer language "Ada," in memory of her presumed status as the "first computer programmer." In 1982, Anthony Hyman wrote a biography of Babbage that is far superior to Moseley's, and that is now considered by most to be the "standard" account of his life. Perhaps because his main focus was Babbage, Hyman was less kind in his assessment of Ada than earlier commentators on her contribution had been. In a footnote, he wrote about Ada's "programs" that after Babbage, some of his assistants, and possibly Herschel Babbage,

Ada was probably about the third or fourth person in the world to write simple programs, if that is the right word for them. She worked under Babbage's careful guidance and they are student exercises rather than original work [emphasis added]. Indeed there is not a scrap of evidence that Ada ever attempted original mathematical work; if she did it would probably have been in her mathematical scrap-book, long since lost.

24. Dorothy Stein (1985) was the first person to write a full biography of Ada who had sufficient mathematical and computer training to reliably assess her contribution. Stein is more responsible than any other individual for the debunking of many myths concerning Ada's life, and for the historical reassessment of Ada's talent and accomplishment. Stein argued that Ada's mathematical understanding was, contrary to popular opinion, always somewhat tenuous. For instance, Stein's assessment of Ada's letters to DeMorgan about calculus between July 1840 and December 1842 -- just before she began work on the translation of Menabrea -- was that although "...they show Ada [to have been] an enthusiastic, active, and adventurous student... they do not take her past the first steps in differential and integral calculus." Stein also questions Ada's grasp of the "mechanical and logical operations of the Analytical Engine, early in 1843..." The evidence in Ada's letters is that she had not been keeping up with developments for some time. She must have learned much from Menabrea's article, and from her conversations with Babbage while writing the Notes. Contrary to Babbage's claim (made more than 20 years later), it does not seem to have been a "subject with which she was so intimately acquainted" when she began her work. Most interesting are Lovelace's claims about the Engine's ability to do algebra. As early as 1836 Babbage had thought that algebra could be mechanized, but he had never worked out the details. Whatever his future plans, however, Stein insists that the version of the Analytical Engine described in Lovelace's Notes was not capable of working algebraic problems. Nevertheless, Lovelace famously wrote, "the Analytical Engine weaves algebraical patterns just as the Jacquard loom weaves flowers and leaves." Why Babbage would have made such an inflated claim is obvious enough: he was hoping that Lovelace's article would help convince the government to renew financial support for his computational venture. Why Lovelace would have made such a claim is a different matter. Either Babbage had convinced her it was true, and she did not know any better, or she was consciously inflating her own rhetoric in order to win support for Babbage. Whichever is true, it is not good for Ada's reputation as a prescient genius of computers.

25. Worried that the various "myths" of Lovelace were rapidly overtaking that the material on which they were based, a college teacher of computer science named Betty Alexandra Toole (1992) published a collection of hundreds of Lovelace's letters, ranging in time from her childhood to just weeks before her death. The correspondents included all the major figures in Lovelace's life: her mother, her husband, her children, DeMorgan, Babbage, Somerville, Greig, and many others. In addition, Toole "narrated" the letters with a 20-page introduction, and frequent interpretive paragraphs interspersed throughout the book. Although the collection is far and away the largest of Lovelace's letters ever published, it suffers from two relatively serious drawbacks. First, it includes only letters from Lovelace, but no responses to her. This makes it difficult to know what others' reactions were to her more unusual claims -- whether prescient or just bizarre. Second, Toole made the decision not to publish any of Lovelace's mathematical correspondence because, she said, it only "represents what she did not know, not what she knew. She only wrote her teachers when she had a problem." Unfortunately, what Lovelace did not know is a very interesting question indeed for the answer would give us a better idea of how to interpret what she wrote in the Notes.

26. The 1990s have been a time for the commercial popularization of the "Ada myth." In 1991, science fiction writers William Gibson and Bruce Sterling raised Ada to the level of popular "cult" figure with the publication of their alternative history novel, The Difference Engine. The premise of the story is that the Analytical Engine (which the authors consistently conflate with the Difference Engine) has been successfully built in the 1820s, and has been an integral part of the rise to power of an Industrial-Radical political party in England, led by none other than Lord Byron. As a result, the computer revolution has arrived in the middle of the 19th century, complete with huge government databases on the citizenry, an electric credit system, "kinetopes" (movies, of a sort), "serinettes" (music players), non-linear dynamics (chaos theory), and international computer espionage. The action centers on the fate of a box of computer punch cards of apparently French origin that seems to be the property of the shadowy "Lady Ada" (she has never married nor adopted the name "Lovelace"). Various factions are attempting to obtain the apparently valuable box of cards, however. The assumption throughout the book is that the cards contain an encoded mathematical system for betting on horses, a vice in which she is widely-believed to indulge in this fictional world. As the story winds down, however, we discover that, in fact, the cards somehow instantiate what we now know as Gödel's Theorem, developed about 75 years early by Ada, and they have been secretly run on the French national computer, "Le Grand Napoléon" by English spies in order to establish a permanent state of unreliability in its "higher functions."

27. In 1997 Ada was used again as the main "character" of a postmodern feminist critique of computer culture by Sadie Plant, the Director of the Cybernetic Culture Research Unit at University of Warwick. The main object of Plant's book, Zeroes + Ones: Digital Women + the New Technoculture (1997), seems to be to argue that women and computers bear a special historical relation to each other such that they can together conspire to undermine the patriarchy. Because women were the computers of the pre-computer era -- serving as weavers, typists, file clerks, and telephone operators -- and because women play such a prominent role in today's computer-assembly plants, high technology will allow women to outnumber men in the workforce, which, it is argued, will give them unprecedented power. Ada is employed by Plant as the primary representative of the special relationship alleged to exist between women and computers.

28. The mass-popularization of Ada's name and image does not stop with a novel and a political tract. The libraries of programs written in the ADA language and sold on CD often carry Ada's face on their cases. All Microsoft software now carries a certificate of authenticity bearing Ada's likeness in the watermark. A biography of Ada has been written by an author (Wade 1994) who specializes in young people's biographies of American heroes (such as Davey Crockett, Sam Houston, and Amelia Earhart). As well, two Yale computer science graduate students have developed a web site entitled "The Ada Project: Tapping Internet Resources for Women in Computer Science" (Freeman & Hupfer 1994). There is an experimental feature-length film entitled "Conceiving Ada" (Hershman Leeson 1997) that includes an appearance by Timothy Leary. The popular web search engine Yahoo! has an entire directory devoted to web sites about Ada Lovelace. More than almost any other woman in the history of math and science -- from Hypatia to Marie Curie -- Ada Lovelace seems to have caught the public imagination as an icon of women's struggle to be treated fairly in scientific circles in the contemporary world.


References & Bibliography

Babbage, Charles. 1994. Passages from the life of a philosopher. New Brunswick, NJ: Rutgers University Press and Piscataway, NJ: IEEE Press. (Original work published 1864)

Babbage, Henry Prevost. (Ed.) 1889. Babbage's calculating engines. Being a collection of papers relating to them; their history, and construction. London: E. & F. N. Spon.

Baum, Joan. 1986. The calculating passion of Ada Byron. Camden, CT: Archon Books.

Boole, George. 1847. The mathematical analysis of logic: Being an essay towards a calculus of deductive reasoning. Cambridge: Macmillan, Barclay, & Macmillan.

Bowden, B. V. 1953. A brief history of computation. In Faster than thought: A symposium on digital computing machines, edited by B. V. Bowden, 3-31. New York: Pitman.

Collier, Bruce. (1990). The little engines that could've: The calculating machines of Charles Babbage. New York: Garland.

Freeman, Elisabeth and Hupfer, Susanne 1994. The Ada project: Tapping internet resources for women in computer science. WWW Document URL: http://www.cs.yale.edu/homes/tap/tap.html.

Gibson, William and Sterling, Bruce. 1991. The difference engine. New York: Bantam Books.

Gunn, Eileen K. 1996. The difference dictionary. WWW document. URL: http://www.sff.net/people/gunn/dd/index.htp. (Originally published in Science Fiction Eye, 1991)

Hartree, Douglas R. 1949. Calculating instruments and machines. Urbana, IL: University of Illinois Press.

Hershman Leeson, Lynn . (director). 1997. Conceiving Ada, a film. Rosenthal, Henry S. and Leeson, Lynn Hershman, (Producers). ZDF/ATRTE, Claudia Tronnier (Executive Producer).

Huskey Velma R. & Huskey, Harry D. 1980. Lady Lovelace and Charles Babbage. Annals of the History of Computing, 2, 299-329.

Huskey Velma R. & Huskey, Harry D. 1985. Title? Annals of the History of Computing, 7, 58-59.

Huskey Velma R. & Huskey, Harry D. 1986. Dorothy Stein's revolutionary view of Ada, Countess of Lovelace. Abacus, 4, 46-54.

Hyman, Anthony. 1982. Charles Babbage: Pioneer of the computer. Oxford: Oxford University Press.

Kneale, William & Kneale, Martha. 1962. The development of logic. Oxford: Oxford University Press.

[Lardner, Dionysius.] 1834. [No title--review of the Difference Engine]. Edinburgh Reivew, No. 120, pp-pp?.

Lovelace, Mary. 1920. Ralph Earl of Lovelace: A memoir. London: Christophers.

Lovelace, Ralph Milbanke. 1921. Astarte: A fragment of truth concerning George Gordon Byron, Sixth Lord Byron. New edition with many additional letters, Edited by Mary, Countess of Lovelace. London: Christophers. (Original version published in 1905)

Lovelace, William. 1848. "On climate in connections with husbandry, with reference to a work entitled 'Cours d'Agriculture, par le Comte de Gasparin...'. Journal of the Royal Agricultural Society, 9, 311-340.

Mayne, Ethel Colburn. 1929. The life and letter of Anne Isabella, Lady Noel Byron. London: Constable.

Menabrea, Luigi F. 1842. Notions sur la Machine Analytique de M. Charles Babbage. Bibliothèque Universelle de Genève, 41, 352-376. (Translation by Augusta Ada Lovelace published 1843 in Scientific Memoirs, 3, 666- ???)

Moore, Doris Langley. 1977. Ada, Countess of Lovelace: Byron's legitimate daughter. London: John Murray.

Morrison, Philip and Morrison, Emily. 1952. The strange life of Charles Babbage. Scientific American, 186 (4), 66-73.

Morrison, Philip and Morrison, Emily (Eds.). 1961. Charles Babbage and his calculating engines; selected writings by Charles Babbage and others. New York: Dover.

Moseley, Maboth. 1964. Irascible genius. London: Hutchinson.

Neumann, B. H. 1973. Byron's daughter. Mathematical Gazette, 57, 94-97.

Patterson, Elizabeth Chambers. 1983. Mary Somerville and the cultivation of science, 1815-1840. Boston: Martinus Nijhoff.

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