William Lawson, teacher of mathematics in Edinburgh, who died in 1757, when employed about twenty years before his death as preceptor to the sons of a gentleman, was induced by his employer to undertake an extraordinary piece of mental calculation. Upon a wager laid by his patron, that the numbers from 1 to 40 inclusive could, by memory alone, be multiplied continually–that is, 1 multiplied 2; the product then arising, 2, by 3; the next product, 6, by 4; the next, 24, by 5; and so on, 40 being the last multiplier–Mr. Lawson was, with reluctance, prevailed upon to attempt the task. He began it next morning at seven o’clock, taught his pupils their Latin lessons in the forenoon as usual, had finished the operation by six in the evening, and then told the last product to the gentlemen who had laid the wager; which they took down in writing, making a line of forty-eight figures, and found to be just. … When the operation was over, he could perceive his veins to start, like a man in a nervous fever; the three following nights he dreamed constantly of numbers; and he was often heard to say that no inducement would ever again engage him in a like attempt. A fair copy of the whole operation, attested by the subscriptions of three gentlemen, parties in the wager, was put into a frame with glass, and hung up in the patron’s dining-room.

— Chambers’s Journal, Sept. 27, 1856