Opening addresses can be found here
(General) and here
An internal picture of the Physics Laboratory (bottom left in the plan) can be seen in After 21 years a publication by W Lewis Jones. Another image this time of the Chemical Lecture Theatre can be seen here.
The plan also shows the ground floor of the old Main Building formerly the Penrhyn Arms Hotel (bottom left) originally built in 1799. The arts and administrative departments moved to the Main Arts Building in 1911. The Science departments moved to their current location on Deiniol Road in 1926.
The pillared enterance to the Penrhyn Arms Hotel is all that now remains of the buildings shown above, it is Grade II listed. Further details can be found in the listed building index here.