Optically Worked Double Concave Glass Lens, 75mm Diameter, 200mm Focal Length Face Size_38mm open at one end for

open at one end for mercury barometer construction and atmospheric pressure demonstrations

equipping a class for fixed-and-movable pulley investigations

Classroom kit for determining relative humidity and dew point using paired dry-bulb and wet-bulb thermometers on a sling handle

Air condenser in borosilicate glass measures 20cm with 19/26 ground joint for high-boiling-point reflux and organic chemistry procedures

Optically Worked Double Concave Glass Lens, 75mm Diameter, 200mm Focal Length Face Size_38mm open at one end forPairs 75mm of aperture with a 200mm diverging focal length on a double concave glass lens, the gentler curvature softening divergence for clearer virtual image observation in refraction setups.