Optically Worked Double Convex Glass Lens, 75mm Diameter, 250mm Focal Length Included_Bosshead Solid glass friction rod that

Solid glass friction rod that develops a positive electrostatic charge when rubbed with silk or wool

Regulated dual AC/DC power supply displaying voltage and current on independent digital readouts

Used to extend the curvature-vs-charge-density study to larger geometries

Twice life-size longitudinal section reveals nasal cavity

Plastic holder atop a 4

Optically Worked Double Convex Glass Lens, 75mm Diameter, 250mm Focal Length Included_Bosshead Solid glass friction rod thatLong focal double convex glass lens at 75mm diameter and 250mm focal length, the f 3. 3 geometry stretching focal throw for distant screen projection of well formed real images.