Optically Worked Double Convex Glass Lens, 75mm Diameter, 1000mm Focal Length Material_Brass the silvery-blue transition metal used

the silvery-blue transition metal used as a hydrocarbon-processing catalyst and in metallurgy student demonstrations

Chrome-plated 60mm reading magnifier extending to a 20cm focal length

Used to add variable resistance while keeping the slide-wire wiper enclosed

Compares 2-

Plastic-bodied wave apparatus with eccentric discs that drive metal rods up and down as the handle turns

Optically Worked Double Convex Glass Lens, 75mm Diameter, 1000mm Focal Length Material_Brass the silvery-blue transition metal usedDesigned for parallel beam refraction work, this 75mm double convex glass lens at 1000mm focal length runs at f 13, near collimated for astronomical analogue and long throw projection setups.