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Stained history: the University’s great glass hall

On a symphony of light.

Image credit: G. A. Bremner

We walk through the university in the fading afternoon light and watch the sun set fire to the stained-glass windows in the Quadrangle. We sit there long after the colours pale and look at the windows, irradiant splendour morphing into something muted. 

The Great Hall has sixteen stained-glass windows. They were originally commissioned by Sir Charles Nicholson in 1858, a graduate of Edinburgh University. The windows hark back to the ancient traditions of Oxford and Cambridge, those at the East and West ends of the hall depicting the colleges and their founders along with their respective courts of arms. An alcove beside the dais is adorned with royal windows consisting of a large central panel on the north wall, and smaller ones high up on the eastern and western walls. These great windows paint portraits of the colleges of Oxbridge and the figures traditionally associated with their founding, though there are multiple discrepancies between fact and fiction. For instance, under the ‘University College’ section, the date and person listed are of the 9th century, the time of King Alfred the Great, though the college was actually founded in 1249 by William of Durham.

The production of stained glass is time-honoured. Coloured glass amulets and beads uncovered in Egypt and Mesopotamia trace the practice back to 2500 BC. The artform flourished in medieval times, with the Christian Church re-popularising the practice with ecclesiastic imagery.  

To make a plate of stained glass, an almost-alchemical reaction is undertaken. Crushing soda ash, sand, and limestone inside a forge, a molten mixture of transparent glass is produced. By introducing metals into the cauldron, colour is infused within the glass. The combinations and interactions of these materials are esoteric. Adding gold will give you a deep ruby, but too little will leave you with a weak cranberry-red. Nickel alone can offer a clear blue, however when further combined with lead the glass takes on a purple glow. The art of producing different shades was historically kept secret, with glass forges having specialised clandestine practises. 

Until recently, there has been no physical answer to the difference in colours of stained glass. Optical microscopes are unable to detect any difference in structure between similar sets of glass, and so the secrets of glassmaking have remained obscured. In 1981, microscopists finally caught up to the elusive glass artisans, with top-of-the-line equipment capable of measuring individual atoms. It was finally revealed that the source of the colours were tiny nanoscale shapes, particles of different metals a thousandth of the size of human cells.

In The Gothic Buildings of the University of Sydney by Bertha McKenzie, a detailed account of each window is provided. The motto of the Colony of New South Wales is above the Oxford Window — Sic fortis Etruria crevit, or ‘thus strong Etruria prospered’ — but that is hardly surprising considering the remaining windows immortalise the likes of James Cook, Edmund Burke, and the British monarchy. The Cambridge Window, donated by Sir Daniel Cooper, has a motto that reads couper fait grandir — ‘cutting down makes for growth.’ 

Yet despite the colonial bent, like that on display in the Hall, the beauty of stained glass comes from something deeper than the motifs on their surface. Countless nanoparticles work in concert to produce a symphony of light, brought alive not by its cold surface and stone-walled frame, but by the rays of the sun which shine through it day-in and day-out. This glass gallery is more dynamic and vibrant than a series of paintings, being innately tied to the natural world that lies outside the silent walls of the Hall. As we sit and watch the light fade, we are buoyed by the knowledge that this gallery of light will open tomorrow at daybreak, and the splendour of the windows will come alive once again.