“If poetry is emotion recollected in tranquility, then science is tranquility recollected in emotion: a struggle to think carefully in the swirl of passionate curiosity.”

Preface.
Source: Lyrical Ballads (1798–1800)

Superman Comes to the Supermarket (1960)

Quoted in New York Post (29 February 1960)
Letters and interviews

Source: Silence: Lectures and Writings

Source: Goodbye to All That (1929), Ch. 27 On studying at Oxford University in 1919.
Context: In the middle of a lecture I would have a sudden very clear experience of men on the march up the Béthune–La Bassée road; the men would be singing... These daydreams persisted like an alternate life and did not leave me until well in 1928. The scenes were nearly always recollections of my first four months in France; the emotion-recording apparatus seems to have failed after Loos.

Source: Lamia's Winter-Quarters (1898), p. 6.

Source: Heaven, Texas

Page 388
The Composer in the Machine Age (1933)

Statement to World Artists : 1950-1980 as quoted n "Grace Hartigan, 86, Abstract Painter, Dies" in The New York Times (18 November 2008)
Unsourced variant: I have found "my subject", it concerns that which is vital and vulgar in American life and the possibility of its transcendence into the beautiful.