The Improvement of the Mind/Advertisment
"Few books have been perused by me with greater pleasure than his 'Improvement of the Mind'; of which the radical principles may indeed be found in 'Locke's 'Conduct of The Understanding'; but they are so expanded and ramified by Watts, as to confer on him the merit of a work in the highest degree useful and pleasing. Whoever has the care of instructing others may be charged with deficiency in his duty if this book is not recommended."
Dr. Johnson's 'Life of Dr. Watts.'