Royal Institution of South Wales (Swansea Museum)

The Royal Institution of South Wales, also known as Swansea Museum, is a two-storey building with a basement, constructed from Bath stone in the style of a temple. It features a fluted Ionic tetrastyle portico with a pediment and steps leading up to it. A dentilled cornice and blocking course extend along the three-bay flanks, which are adorned with Doric pilasters, a blind upper storey, a band course, and ramped, lugged architraves on the ground floor. The building has sash windows with marginal glazing bars. The central doorcase has a ramped architrave, a fanlight, and double doors decorated with anthemion panels.

To the right, there is a one-bay return elevation, and a low top-lit gabled rear extension with a blocked arched keyblocked doorway. The left end features a three-bay return with a similar low top-lit gabled rear extension, along with modern extensions in the angle.

The property is complemented by original ironwork railings with scrolled supports that curve forward to the left and right of the portico. These are supported by tapered panelled piers made of cement with entablatures. The railings continue on the right to connect with a low rubble boundary wall, which extends as a crinkle-crankle wall to the rear, and on the left to meet another rubble boundary wall along Adelaide Street.

Inside, the building retains an entrance hall with ramped architraves and double doors leading to a library on the right and a lecture hall on the left. The library features mahogany bookcases on two levels, open balustered stairs, and fluted columns with acanthus capitals on the ground floor, while the rest of the detailing is plain. A fine Imperial stone staircase with original cast-iron square balusters ascends from the rear of the entrance hall. The interior of the rear right-hand hall, which was formerly the Reference Library and Reading Rooms, has a timber trussed roof with ironwork foliage spandrels, paired pilasters with swagged capitals for display cases, a wide pilastered end doorcase, and a segmental arched recess. The small rear left-hand hall, previously the Art Gallery and Museum, also has a timber trussed roof, featuring metal tie-rods and circled spandrels.