A French Drum Microscope dating from circa 1860 with it's original case which has a recess in the lid to accept the microscope base for stability during use, the case measures 8.5cm in width. This type of microscope was also referred to as the Bertrand "Furnace" Microscope, designed for portability and durability. The "Furnace" nickname is a reference to the shape, resembling a furnace. These microscopes are associated with the work of French optician, François Bertrand.