Letter from Charles Dickens to a chimney sweep, March 15, 1864:

Dear Sir,

Since you last swept my study chimney it has developed some peculiar eccentricities. Smoke has indeed proceeded from the cowl that surmounts it, but it has seemingly been undergoing internal agonies of a most distressing nature, and pours forth disastrous volumes of swarthy vapour into the apartment wherein I habitually labour. Although a comforting relief probably to the chimney, this is not altogether convenient to me. If you can send a confidential sub-sweep, with whom the chimney can engage in social intercourse, it might be induced to disclose the cause of the departure from its normal functions.

Faithfully yours,

Charles Dickens