Richard Cumberland

Thomas Davies, in Life of Garrick (1780) 2:275.

Mr. Cumberland is unquestionably a man of very great abilities; it is his misfortune to rate them greatly above their value; and to suppose that he has no equal. There are many writers in this metropolis whose merit is not inferior to that of this gentleman; he is one star in the same firmament, where many others shine with equal brightness. Mr. Cumberland should consider too, that an author, by too much indulging the fluency of his fancy, and the rapidity of his pen, may possibly write below himself. Let his Pegasus go to grass for a reasonable time, and he will return to the race with renewed vigour.

He is too young a man to have the advice of Horace applied to him, "Solve senescentem, mature sanus, equum." But, as a man sometimes makes himself old before his time, by great and continued intemperance; so may an author, by writing too fast, exhaust his stock of genius.