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Comments, Queries, and Debate: Babbage Studies Disclosure Number: IPCOM000129623D
Original Publication Date: 1989-Jun-30
Included in the Prior Art Database: 2005-Oct-06
Document File: 2 page(s) / 16K

Publishing Venue

Software Patent Institute

Related People

Anthony Hyman: AUTHOR [+2]


38A Downshire Hill Hampstead NW3 1NU England

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Copyright ©; 1989 by the American Federation of Information Processing Societies, Inc. Used with permission.

Comments, Queries, and Debate: Babbage Studies

Anthony Hyman

38A Downshire Hill Hampstead NW3 1NU England

In his article "Charles Babbage's Table of Logarithms (1827)" (Annals, Vol. 10, No. 3, 1988, pp. 159-169), Martin Campbell-Kelly writes that I asserted or implied "that Babbage calculated the tables" ab initio. This is not so. It is a commonplace of the history of table-making that many, perhaps most, tables were made by comparison of existing tables rather than by complete calculation or recalculation. The idea that Babbage could have calculated the whole set of tables as a sideline, when he was engaged not only in the first Difference Engine but in collection material for what was to become The Economy of Machinery and Manufacture, patently absurd, and nothing was further from my thoughts. Nor did Babbage at that date, before his father died, have thc funds to pay computers, even if he had wished to do so.

When preparing Babbage's biography, I necessarily collected a great deal of material which could not be included, either for want of space or because it was not appropriate to a general biography. It was actually my original intention to prepare a technical history of the Calculating Engines. After the work had proceeded some way, it was, for reasons which need not concern us here, replaced by a general biography, and my technical work on the Engines has not been published. However, if neither thc history of the Engines, nor most assuredly the preparation of Babbage's logarithmic tables, presented any particular difficulties when preparing the biography, many aspects of his life and work did and still do present major problems. I would like to outline at least a few of these in the hope of stimulating further Babbage studies.

(Image Omitted: Figure 1. Photomicrograph of gear teeth of Difference Engine No. l.)

Some 15 or 16 years ago, the late Maurice Trask and I found that some dimensions of the gear wheels of the first Difference Engine were made with a reproducibility of about 0.002" (not accuracy of 0.002", be it noted, which raises other questions). In 1975, at my request, some photomicrographs of the gear teeth were made in the Department of Mechanical Engineering at Imperial College, and the profiles of the gear teeth were determined (Figure 1). The teeth are beautifully formed, with a profile intermediate between an involute and a cycloid, and one can see clearly the mar...