“It seldom happens, however, that a great proprietor is a great improver.”

Introductio ad prudentiam: Part II (1727), Gnomologia (1732)

Action and Study
The Note-Books of Samuel Butler (1912), Part IX - A Painter's Views on Painting

Source: 1910s, Prejudices, First Series (1919), Ch. 16
Context: The great artists of the world are never Puritans, and seldom even ordinarily respectable. No virtuous man — that is, virtuous in the Y. M. C. A. sense — has ever painted a picture worth looking at, or written a symphony worth hearing, or a book worth reading.

From a book review in The New York Times (9 May 1976) http://select.nytimes.com/gst/abstract.html?res=F40F13FC345E157493CBA9178ED85F428785F9#, also quoted in The American Mathematical Monthly (December 1994)
Context: Biographical history, as taught in our public schools, is still largely a history of boneheads: ridiculous kings and queens, paranoid political leaders, compulsive voyagers, ignorant generals — the flotsam and jetsam of historical currents. The men who radically altered history, the great scientists and mathematicians, are seldom mentioned, if at all.

Book IV, line 702 (tr. J. D. Duff).
Pharsalia

Second Speech on Conciliation with America (1775)