Binocular compound microscope mounted on a horseshoe base. Two tapered pillars inserted in the base hold the tilting stage to which is attached the telescopic tube carrying the illumination mirror and binocular body-tube, which provides three-dimensional viewing. Under the stage are two revolving disks with filters, diaphragms, and condenser lenses. Coarse focus is by rackwork. Fine focus is by a knob. There is a second binocular body-tube. This instrument may be connected with the experiments with binocular microscopes by Filippo Pacini in 1853-54.