Young temperament

In music theory, Young temperament is one of the circulating temperaments described by Thomas Young in a letter dated 9 July 1799, to the Royal Society of London. The letter was read at the Society's meeting of 16 January 1800, and included in its Philosophical Transactions for that year. The temperaments are referred to individually as Young's first temperament and Young's second temperament, more briefly as Young's No. 1 and Young's No. 2, or with some other variations of these expressions.

Young argued that there were good reasons for choosing a temperament to make "the harmony most perfect in those keys which are the most frequently used", and presented his first temperament as a way of achieving this. He gave his second temperament as a method of "very simply" producing "nearly the same effect".