Optics

Dense flint glass, refractive index 1.620 to 1.623.

For measurement on two axes, with horizontal and vertical scales, heavy stand with leveling screws, and a carriage fitted with micrometer screw for fine adjustment. Another sliding carrier is provided on vertical bar also with micrometer screw for fine adjustment. Microscope tube is fitted with rack and pinion focusing. Stainless steel scales and verniers, horizontal scale 160 mm with vernier reading to 0.01 mm and vertical scale 140 mm with vernier reading to 0.01 mm. Ramsden eye-piece x 10 with crossline graticule and 50mm focus objectives Magnifier is provided to read vernier.