• Newton took no exercise, indulged in no amusements, and worked incessantly, often spending eighteen or nineteen hours out of the twenty-four in writing.

    W. W. Rouse Ball: Newton took no exercise, indulged in no amusements, and worked incessantly, often spending eighteen or nineteen hours out of the twenty-four in writing.
    W. W. Rouse Ball (2012). “A Short Account of the History of Mathematics”, p.287, Courier Corporation