In the following text of Pamela by Samuel Richardson, well is capitalised — possibly to denote speech, where inverted commas have been neglected. As GEdgar points out, this is not an isolated case. I wonder why only, but there may be no explanation:
He took my hand, in a kind of good-humoured mockery, and said, Well urged, my pretty preacher! When my Lincolnshire chaplain dies, I'll put thee on a gown and cassock, and thou'lt make a good figure in his place.—I wish, said I, a little vexed at his jeer. Well, well, Pamela, said he, no more of this unfashionable jargon.