Metal Refraction and Reflection Apparatus Prong_3 Wall-mounted Mason's hygrometer with two

Wall-mounted Mason's hygrometer with two identical dual-scale thermometers — one dry and one kept wet via a water reservoir — calculating relative humidity from their paired reading difference

illustrating additive color mixing

and friction rods for a full unit on charging

each topped with a small handling knob and stored in a hardwood block for classroom balance coursework

Metal Refraction and Reflection Apparatus Prong_3 Wall-mounted Mason's hygrometer with twoMetal built apparatus designed for measuring incidence, reflection, and refraction angles when light crosses a boundary between media of different optical density.