Nay, Madam, when you are declaiming, declaim; and when you are calculating, calculate.
Source: Retort to Hester Thrale, quoted in: James Boswell, Life of Samuel Johnson, 26 April 1776 (1791).
-- Samuel Johnson, (Sep 18 1709-1784), English lexicographer, critic; He was remembered for writing the first critique of Shakespeare, 1765 and Dictionary of the English Language, 1755.