Superior Wooden Test Tube Support, 12-Place Entomology & Zoology_Entomology Supplies showing how inclination shifts from

showing how inclination shifts from horizontal at the equator to vertical at the poles

Convertible motor-generator running AC or DC in shunt or series wound configurations

the medium-strength option for classroom investigations into magnetic poles and field-line geometry

5-inch plate-and-rod assembly with central mass

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

Superior Wooden Test Tube Support, 12-Place Entomology & Zoology_Entomology Supplies showing how inclination shifts fromTwelve place hardwood test tube rack combining ten 19 mm holes and two 25 mm holes with twelve draining pins for mixed size storage and inverted drying on the bench.