103, Princess Street

No. 103 on Princess Street is a Mechanics' Institute, now functioning as a museum. Built in 1854 by J.E. Gregan, the building has been altered and internally remodelled. It features red brick in Flemish bond with sandstone dressings, and is set on an irregular plan within a parallelogram on an island site. Designed in the Italian palazzo style, the structure stands three storeys high with a cellar and an added attic, comprising seven symmetrical bays.

The building has a stone plinth, sill-bands on all floors, a plain frieze, a modillioned cornice, and a high pilastered parapet that conceals the added attic. The central round-headed doorway is framed by a moulded stone surround and topped with a prominent cornice supported by consoles. Each floor has tall 4-pane sashed windows, all featuring moulded architraves. The ground floor windows have cornices, aprons, and raised sills on large brackets, while the first-floor windows are adorned with segmental pediments on consoles and blind-balustraded aprons linked by a band.

On the left return wall, there is one bay in matching style with a lettered plaque near the front corner. This wall then breaks forward, revealing a large tripartite window on each floor, both with stone surrounds, though the upper window is larger and features round-headed lights. Historically, this building is significant as it hosted the first Trades Union Congress.