John Campbell (1708-1775)
From 18th Century Literary Anecdotes

DR. CAMPBELL, looking once into a pamphlet at a bookseller's shop, liked it so well as to purchase it; and it was not till he had read it half through that he discovered it to be of his own composition....

Campbell was a prolific miscellaneous writer of considerable ability and wide general knowledge. Dr. Johnson was well acquainted with him, and had a sort of amused respect for a man who wrote at once so much and so well, and whom he once described as 'the richest author that ever grazed the common of literature'. He was prepared to concede that Campbell was not always rigidly truthful in his conversation, but he found no such carelessness in his books ('Campbell will lie, but he never lies on paper'). At one time Johnson was a frequent visitor at Campbell's house:

'I used to go pretty often to Campbell's on a Sunday evening, till I began to consider that the shoals of Scotchmen who flocked about him might probably say, when anything of mine was well done "Ay, ay, he has learnt this of CAWMELL!"

Boswell, Life of Johnson, i. 417-18.
also Biographia Britannica (1789), iv (Corrigenda and Addenda to vol. iii)

Once, when the conversation turned on Campbell, Johnson mentioned that he had married 'a printer's devil'.

REYNOLDS. 'A printer's devil, Sir! Why, I thought a printer's devil was a creature with a black face and in rags.'
JOHNSON. 'Yes, Sir. But I suppose he had her face washed, and put clean clothes on her. (Then looking very serious, and very earnest.) And she did not disgrace him; the woman had a bottom of good sense.'

The word bottom, thus introduced, was so ludicrous when contrasted with his gravity that most of us could not forbear tittering and laughing; though I recollect that the Bishop of Killaloe kept his countenance with perfect steadiness, while Miss Hannah More slyly hid her face behind a lady's back who sat on the same settee with her. His pride could not bear that any expression of his should excite ridicule when he did not intend it; he therefore resolved to assume and exercise despotic power, glanced sternly around, and called out in a strong tone, 'Where's the merriment?' Then collecting himself, and looking awful, to make us feel how he could impose restraint, and as it were searching his mind for a still more ludicrous word, he slowly pronounced, 'I say the woman was fundamentally sensible'; as if he had said, hear this now, and laugh if you dare. We all sat composed as at a funeral.

Boswell, Life of Johnson, , iv. 99.