George Birkbeck Norman Hill,
The Life of Sir Rowland Hill and the History of Penny Postage…
“ In order that economic improvement may not be [403] unduly encumbered with fixed arrangements, it would be well to limit the duration of all future contracts to some moderate period, say three years; but, under this restriction, it is very desirable for the sake of economy, and for other important considerations, that the contract system should be greatly, though gradually, extended. ”
