perpetuum mobilen.

a1688 R. Cudworth Treat. Freewill (1838) 28 This is an ever bubbling fountain in the centre of the soul, an elater or spring of motion, both a primum and a perpetuum mobile in us, the first wheel that sets all the other wheels in motion, and an everlasting and incessant mover.

1755 J. Smeaton Diary 1 July in Journey to Low Countries (1938) 32 The principle of its motion must be either that of human Strength or a perpetuum mobile.

1861 H. Dircks (title) Perpetuum mobile, or a history of the search for self-motive power.

1904 B. Russell in Mind 13 337 ‘There is no perpetuum mobile’ does not mean ‘whatever exists differs from the perpetuum mobile’.

1964 V. Nabokov Defence x. 162 The passionate chess player is just as ridiculous as the madman inventing a perpetuum mobile.

2001 O. Sacks Uncle Tungsten xxi. 264 Radium at first appeared to do exactly that—to be a perpetuum mobile, a free lunch, a steady and inexhaustible source of energy.

1953 E. Wilkins & E. Kaiser tr. R. Musil Man without Qualities I. xxxiv. 152 What makes a perpetuum mobile of this yearning for the renovation of life is nothing but the calamity that [etc.].

1983 G. Barker Coll. Poems (1987) 757 The conundrum of prime numbers' perpetuum mobile.

1992 N.Y. Times Bk. Rev. 13 Sept. 1/3 Macaulay gave an impression of perpetuum mobile in both her work and her life. ‘Nobody ever zigzagged more,’ said the literary editor Alan Pryce-Jones, ‘either driving a car or walking through life.’