JF Ptak Science Books Post 2739
George Parker Bidder (1806-1878) gave a lecture (without notes) explaining to the audience at the Institution of Civil Engineers in 18561 his interior practices and habits in performing absolutely prodigious and complex arithmetical feats entirely in his head. He was among the first tier of performing human calculators (like Zerah Colburn, b. 1804) mental calculations enchanted large audiences from the stages, answering seemingly impossible questions with accuracy and speed. It is in the 1856 paper (which Martin Gardner refers to as "historic2" and "valuable") that he relates some of the practices which clarify his process--for example, one large element was that he would keep one fact in his head at a time, until it was finished, and then move on. Of course for people who did not have anything even remotely resembling this impossible ability, the information is interesting, though I have no idea how useful it may be...unless you were already a savant, that is. Some things are just not to be known by mere mortals. Like the probably-apocryphal story of someone asking Hans Bethe how Richard Feynman had solved--on his feet--some impossible something, and Bethe responds: "First he thinks very very hard....and then he gets the answer".) Something like that.
In any event, here's the article, reproduced by Devonshire Perspectives website. My own copy is in a tightly-bound volume from the proceedings, and no doubt I would have broken the spine trying to copy the thing. That said, if anyone wants to buy this volume, it is for sale--this is a book selling site, sorta, after all.
The full lecture by Bidder:
- Bidder, George Parker. "On Mental Calculation", in Minutes of Proceedings of he Institution of Civil Engineers with Abstracts of the Discussions, volume XV, Session 1855-6, London, published by the Institution, pp 251-280 in the 534pp volume.
2. Gardner, Martin. "Mathematical Games", in Scientific American, 216/4, April 1967, p. 117.
Also, I found an interesting biographical treatment of Bidder:
- Bidder, George Parker. Mental Arithmetic. A short account of George Bidder, the celebrated mental calculator: with a variety of the most difficult questions, proposed to him at the principal towns in the kingdom, and his surprising rapid answers, etc. by George Parker BIDDER Rapid Calculator and Engineer., 1821
It seems as though there was a separate edition of this 1856 lecture tens years later, published by Clowes:
- Bidder, George Parker, and Institution of Civil Engineers (Great Britain). On Mental Calculation. Edited by Charles Manby. London: Printed by W. Clowes, 1866.
And another printing somewhat later:
- Bidder, George Parker. On Mental Calculation. London: Printed by W. Clowes, 1886.