When the citizens proposed to erect a mansion-house for their lord mayor, they fixed on Stocks-market, where the Mansion-house now stands, for its site, and proposed to arch the Fleet-ditch, from Holborn to Fleet-street, and to remove that market to the ground they would gain by that measure. In 1733, therefore, they represented to the House of Commons, that although after the Fire of London the channel of the Fleet had been made navigable from the Thames to Holborn-bridge, yet the profits from the navigation had not answered the charge; that the part from Fleet-bridge to Holborn-bridge, instead of being useful to trade, had become choked with mud, and was therefore a nuisance, and that several persons had lost their lives by falling into it. For these and other causes assigned, an act passed, vesting the fee simple of the site referred to in the corporation for ever, on condition that drains should be made through the channel, and that no buildings on it should exceed fifteen feet in height. The ditch was accordingly arched over from Holborn to Fleet-bridge, where the present obelisk in Bridge-street now stands, and Fleet-market was erected on the arched ground, and opened with the business of Stocks-market, on the 30th of September, 1737. In 1765, the building of Blackfriars-bridge rendered it requisite to arch over the remainder, from Fleet-bridge to the Thames; yet a small part remained an open dock for a considerable time, owing to the obstinate persistence of a private proprietor.[25] Previous to the first arching of the Fleet, Pope, in “The Dunciad,” imagined the votaries of Dulness diving and sporting in Fleet-ditch, which he then called The king of dykes! than whom no sluice of mud With deeper sable blots the silver flood. “I recollect,” says Pennant, “the present noble approach to Blackfriars-bridge, the well-built opening of Chatham-place, a muddy and genuine ditch.” It has of late been rendered a convenient and capacious sewer. * * * * *