Sorrow is tranquillity remembered in emotion. SeeWordsworth 925:10.

-Parker, Dorothy ne¤  e Rothschild
 Here Lies,'Sentiment'.

Passionless bride, divineTranquillity, Yearned after by the wisest of the wise, Who fail to find thee, being as thou art Without one pleasure and without one pain.

-Tennyson
  'Lucretius',1.265^8.

'Humour,' he said,'is emotional chaos remembered in tranquillity.' SeeWordsworth 925:10.

-Thurber,James Grover
  In the NewYork Post, 29 Feb.

Poetry is the spontaneous overflow of powerful feelings: it takes its origin from emotion recollected in tranquillity.

-Wordsworth,William
  Preface to Lyrical Ballads (2nd ed.1802; Lyrical Ballads first published1798, preface added1800, enlarged1802).

It is a beauteous evening, calm and free, The holy time is quiet as a nun Breathless with adoration; the broad sun Is sinking down in its tranquillity; The gentleness of heaven broods o'er the sea: Listen! the mighty being is awake, And doth with his eternal motion make A sound like thunderöeverlastingly.

-Wordsworth,William
  'It is a beauteous evening calm and free', l.1^8 (published 1807).