The 1753 Supplement volumes form a very important complement to the main work, though they are seldom found with it. The content was based on notes left by Chambers on his death, which were then expanded by the mathematician George Lewis Scott and others.
The Two volumes of the Supplement here found bound as three
The Ex Libris of Galfridi Barrovi
Notes on Chambers by Barrovi
Notes on Chambers by Barrovi, and mention of the three Supplement volumes