The Philosophical Review/Volume 1/Summary: Richet - Maudi et le calcul mental
The investigation of Maudi, the French 'lightning calculator,' seems to show that he is more remarkable for memory than for the rapidity or depth of his calculations. Thus he took ten minutes to perform the following five operations: 1st, addition of 22,423, 379,999, 823,111, 79,437; 2d, square of 940, and square of 953; 3d, division of 482,765 by 4760; 4th, cube root of 121,287,375; 5th, fifth root of 847,288,609,493. Of the ten minutes taken to perform the above, about five were devoted to repeating the numbers as they were given out. Good professional calculators could work out on paper and in about the same time all that Maudi did mentally; in fact, he simply used his extraordinary memory for figures where the common calculators used pen and paper. Whether his memory was auditory, neural, or motor was not determined: Maudi himself called it 'auditory,' but did not clearly understand what the term meant.