The geological museum on the first floor, c. 1900 .The cornice was decorated gold scrolls and red and blue denticles.

A building is a combination of the needs of the client, the imagination of the architects, and the constraints imposed on the building contractor.  Following the opening of a new structure the utilisation of a building and its space may change, and in particular a structure erected in an educational establishment such as Trinity College Dublin is subject to the changes in pedagogical practices, and demographic and political stresses.

The Museum Building is no exception: from the initial submission of architectural plans and specifications in 1853, and throughout the construction phase, alterations were being suggested and made at the behest of the Board of Trinity College the client and academic occupant of the building, and the architects Thomas Deane, Son and Woodward and the contractors Gilbert Cockburn and Sons.

The building was designed to house the School of Engineering that also contained the sub-discipline of Geology, and the School of Divinity also obtained some space.  Later the Law School similarly spent some time in occupancy as did Economics, but today the building houses the Disciplines of Civil Engineering, Geology and Geography.

In August 1857 when the Museum Building was officially opened during the British Association for the Advancement of Science meeting held in Dublin, the delegates would have entered the front door into the outer and inner hallways and been dazzled by the polychromic effect produced by the columns of Irish and foreign stone and the brickwork in the domes.  They would have descended flights of stirs to sit in airy lecture theatres in the south-east and south-west corners, the latter being known as the ‘Bear Pit’.

Floor plan of the Museum Building drawn up by John McCurdy in 1853 [Civil Engineer and Architect’s Journal, 1855, p. 48].

Seventeen rooms originally surrounded the cathedral-like hallway on the ground- and first-floor levels, and included several lecture theatres, a large Library (now the Freeman Library), several offices for academics, a room for Experimental Philosophy (Physics),a Drawing Office for Engineering and two large museums for geological specimens and engineering models.

 Longitudinal section drawn through the rooms along the north façade showing original room scheme (above) compared to that of today (below).

Since the late-1940s the original lecture theatres and other rooms have been subdivided in several phases, both vertically and horizontally, so that today eighty-five rooms occupy these original spaces.