Dyson Perrins Chemistry Laboratory

The Dyson Perrins Chemistry Laboratory is a building dating to 1915, constructed of red brick with ashlar dressings. It comprises a long range with east and west wings flanking a central entrance hall and main stair, with a secondary stair at the end of the west wing. The site is split-level, incorporating a lower ground floor with a longitudinal corridor and small laboratories, and an upper level with large, double-height laboratories on either side. Later extensions to the rear are not of special interest.

The main elevation features a projecting frontispiece three windows wide, and wings of five and six windows wide to the left and right. The frontispiece has a stone ground floor with a door case featuring large scrolled brackets supporting a flat roof and a first floor comprised of Ionic columns, flanked by two sash windows. Three windows are positioned on the second floor with straight stone festoons. A prominent cornice with deep dentil moulding runs along the frontispiece, and a stone parapet with three short ranges of balustrade tops the elevation. The cornice and dentil moulding continue to the lower wings, with a run of balustrade in a brick parapet corresponding to each window bay below. The wings are defined by tall windows with stone frames to the double-height first and second floors, featuring multi-pane glazing with prominent curved glazing bars. The west wing has a tall stone plinth at ground floor, while the east wing features stone aprons below the shorter upper windows, with a ground floor sash window of almost equal height. Wide horizontal brick quoins define the corners. A stone plaque on the facade reads "balliolensis feCI hydateoCVs o sI MeLIVs", which, when the larger letters are interpreted as Roman numerals, resolves to the number 1915 – the building's intended completion date. A smaller inscription combines the names of the laboratory's two 'founding fathers', Perkin and Perrins.

The right-hand return elevation mirrors the main elevation with a range of five window bays. To the extreme left is a lower section, contemporary with the west wing, featuring three segmental-arch-headed, multi-pane windows and a projecting porch. The porch roof has a broken stone pediment with a large keystone to the segmental-arch window below, flanked by straight festoons. A frieze with stone wreaths features to the front and one wreath to the side elevation, where the frieze and cornice continue. Two round portals hang from the frieze with brackets. Round-headed windows follow the interior stair. Large multi-pane windows and wide stone banding mark this side elevation, stepping back irregularly to follow a service road. The rear elevation is similar to the front, with four engaged Ionic columns supporting a frieze inscribed "alchymista spem alit aeternam" ('chemistry offers eternal hope').

The interior features a main staircase in the hall with stone piers and abstract capitals. Corridors are finished with half-height green and white glazed tiles, and contain interior transoms. The large laboratory on the first floor to the left includes wood laboratory tables with porcelain basins, and a long skylight framed with metal arches and dentil moulding.