A Memoir of Zerah Colburn: Written by Himself. Containing an Account of the First Discovery of His Remarkable Powers; His Travels in America and Residence in Europe; a History of the Various Plans Devised for His Patronage; His Return to this Country, and the Causes which Led Him to His Present Profession; with His Peculiar Methods of Calculation

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G. and C. Merriam, 1833 - Mathematicians - 204 pages
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Page 15 - That such calculations should be made by the powers of mind alone, even by a person of mature age, and who had disciplined himself by opportunity and study, would be surprising, because far exceeding the common attainments of mankind ; — that they should be made by a child six years old, unable to read, and ignorant of the name or properties of one figure traced upon paper, without any previous effort to train him to such a task, will not diminish the surprise.
Page 14 - Questions in multiplication of two or three places of figures, were answered with much greater rapidity than they could be solved on paper. Questions involving an application of this rule, as in Reduction, Rule of Three, and Practice, seemed to be perfectly adapted to his mind.
Page 11 - Sometime in the beginning of August, 1810, when about one month under six years of age, being at home, while his father was employed at a joiner's work-bench, Zerah was on the floor, playing in the chips ; suddenly he began to say to himself, ' 5 times 7 are 35 — 6 times 8 are 48, &c.' His father's attention being arrested by hearing this, so unexpected in a child so young, and who had hitherto possessed no advantages, except perhaps six weeks...
Page 38 - ... sixteenth power. And in naming the last result, viz., 281,474,976,710,656! he was right in every figure. He was then tried as to other numbers consisting of one figure, all of which he raised...
Page 171 - Supposing I have a corn field, in which are 7 acres, having 17 rows to each acre ; 64 hills to each row ; 8 ears on a hill, and 150 kernels on an ear; how many kernels on the corn field ? 9,139,200.
Page 38 - He was asked the square root of 106,929> and before the number could be written down, he immediately answered 327. He was then required to name the cube root of 268,336,125, and with equal facility and promptness he replied 645.
Page 38 - ... by mentioning 941 and 263, which indeed are the only two factors that will produce it. Another of them proposed 171,395, and he named the following factors as the only ones, viz.: 5x34279, 7x24485, 59x2905, 83X2065, 35X4897, 295x581, 413X415.
Page 39 - ... his calculations, but for nearly three years he was unable to satisfy their inquiries. There was, through practice, an increase in his power of computation ; when first beginning, he went no farther in multiplying than three places of figures ; it afterwards became a common thing with him to multiply four places by four ; in some instances five figures by five have been given.
Page 180 - In extracting the Square Root, his first object was to ascertain what number squared would give a sum ending with the two last figures of the given Square; and then what number squared will come nearest under the first figure in the given square when it consists of five places. If there are six figures in the proposed sum, the nearest square under the two first figures must be sought, which figures combined will give the answer required. ' Suppose it be required lo extract the square root of 92,416.
Page 77 - Dr. Gall, well known as the author of the System of Craniology, was then in Paris, and by means of his tutor, Zerah was introduced to him, without the doctor's having any previous intimation of the character of his visiter.

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