Observatory Tower, At Walton Lodge 10 Metres West Of House

The Observatory Tower, located at Walton Lodge 10 metres west of the house in Great Amwell, is a two-storey structure built in the 18th century. It was relocated to its current site by the Mylne family between 1822 and 1839. Originally constructed by Mr. Hodson of Hoddesdon about half a mile southeast of the village, the tower is made of buff brick with a short upper section featuring weatherboarded timber framing. It has a conical roof covered in tiles, topped with lead and a ball finial. The roof is essentially square in shape but has a segmental convex curve on each side.

The tower features a wide boarded soffit with a shaped bracket at the centre. Its square structure is supported by wide corner pilaster buttresses, a projecting floor band, and corbelled dentilled courses beneath the timber-framed section. There is a large round-headed blocked opening with a low sill on the east side and on the ground floor to the east and west. The upper floor has a recessed sash window with a flat gauged arch, where the upper sash is three times higher than the lower sash. The lower opening has been blocked with riven laths and plastered.