Six, or at most seven, hours' sleep is, for a constancy, as much as you or anybody else can want; more is only laziness and dozing, and is, I am persuaded, both unwholesome and stupefying.
"Lord Chesterfield's Advice to His Son, on Men and Manners: Or, A New System of Education". Book by Philip Dormer Stanhope Earl of Chesterfield, 1815.