"There can be no doubt but that he who has the most materials has the greatest means of invention; and if he has not the power of useing them, it must proceed from a feebleness of intellect; or from the confused manner in which those collections have been laid up in his mind."
— Reynolds, Joshua (1723-1792)
Text from A Discourse Delivered to the Students of the Royal Academy, on the Distribution of the Prizes, Dec. the 10th, 1774. By the President. (London: Printed for Thomas Davies, 1775). <Link to ECCO>
See also Sir Joshua Reynolds, Seven Discourses Delivered in the Royal Academy by the President (London: T. Cadell, 1778). <Link to Google Books>
Also reading at PGDP.