Glass plate negative of a three-quarter length portrait of Sir James Clark (1788-1870), physician-in-ordinary to Queen Victoria between 1837 and 1860. He is presented seated, facing a quarter to the right and looking at a thermometer he holds in his right hand and places on a desk beside him. He rests his left ankle on his right knee.

The glass plate negative has been photographed showing the coated side and therefore the image appears laterally reversed. Prints from this negative do not seem to exist in the Collection, however a variant from the same sitting is represented by RCIN 2910422.