This plaque is located outside the door of Calne library and reads:
Jan Ingen Housz
The Dutch physician, Jan Ingen Housz MD, FRS (1730-1799) was doctor in the Austrian Royal Family but was in England in 1779. Before returning to Vienna he spent that summer performing over 500 experiments in a house near London.
These proved, for the first time, that the green parts of plants absorb carbon dioxide and release oxygen in sunlight: in other words they purify the air we breathe. At the same time the carbon absorbed is converted to starch so that plants are also the ultimate source of all our food. We therefore commemorate the genius of Ingen Housz, the discoverer of what we now cal photosynthesis.
He returned to live in England later in life and was a frequent guest at Bowood House, where he died. He is buried in Calne, in a vault under St. Mary's Church.
The decorative paving was created by members of the Calne Artists Group: David Reeves the overall design and ceramic leaves, Vivien ap Rhys Price the head of Ingen Housz from a 1768 medallion. Photocast of Liverpool cast the bronze.