The mechanism of the clock which was designed in 1610 by Leonard Tenant was removed from the turret of Cassiobury House and is now on public display in the British Museum as an example of a seventeenth century tower clock. A set of 12 late medieval stained-glass roundels depicting the Labours of the Months which had been installed in Cassiobury House during the 19th century was purchased by the Victoria and Albert Museum. The V&A also possesses a carved limewood overdoor/picture surround and cornice portion by Grinling Gibbons. The Watford Museum has acquired a number of paintings from the collection of the Earl of Essex, including a view of Cassiobury House by J. M. W. Turner, a landscape painting of the estate by John Wootton and an interior painting of the Winter Dining Room by William Henry Hunt, along with several portraits of Earls of Essex and their family members painted by Sir Peter Lely, the school of William Wissing, Enoch Seeman, Sir Godfrey Kneller, Andrea Soldi, Sir Joshua Reynolds and Sir Thomas Lawrence, among others. The Capel family by Cornelius Johnson, formerly at Cassiobury is now on display at the National Portrait Gallery in London.