Optically Worked Double Concave Glass Lens, 75mm Diameter, 150mm Focal Length Category_Science Gifts Sturdier-than-glass metal displacement vessel at

Sturdier-than-glass metal displacement vessel at 100 by 50mm with a side spout

two adjustment screws on a spring-loaded aluminum bar

supporting 18 mm thermometers upright and protected between laboratory uses

Square-topped wooden screw simple-machine model with a leverage block

9A with oxidized constantan winding on a vitreous-enameled steel tube and a phosphor-bronze sliding contact

Optically Worked Double Concave Glass Lens, 75mm Diameter, 150mm Focal Length Category_Science Gifts Sturdier-than-glass metal displacement vessel atOptically worked double concave glass lens at 75mm diameter and 150mm focal length, the diverging curvature producing virtual upright images for refraction and beam spreading work.