Found it on this webpage:
POEMS FROM
A POCKETFUL OF PEBBLES
by "Jan Struther"
(Joyce Maxtone Graham, later Mrs A. K. Placzek, 1901-1953)
author of Mrs. Miniver.
http://digital.library.upenn.edu/women/ ... ebble.html
Quote:
ALL CLEAR
IT TOOK me forty years on earth
To reach this sure conclusion:
There is no Heaven but clarity,
No Hell except confusion.