Pritchard was apprenticed to his cousin Cornelius Varley, an artist deeply interested in science. For his improvements in the camera lucida, the camera obscura and the microscope, Cornelius Varley received the Isis Gold Medal of the Society of Arts and later, at the Great Exhibition, he gained a medal for his invention of the graphic telescope. Cornelius's brother was the painter John Varley, but Pritchard would have seen more of Cornelius's son Cromwell Fleetwood Varley, an engineer who pioneered the transatlantic telegraph cable.