Opsiometer

See OPTOMETER. Opt at i an us, PUBLILIUS, 4th cent. Latin poet. Optical Bench. Apparatus for studying the phenomena of diffraction. It con- sists e entially of a graduated bar carry- ing three upright holders sliding along the bar. The first car- ries a laterally adjust- able Ramsden's eve- piece, furnished with a set of cro -wires. The second and third uprights carry the va- rio us diffraction app a- ratus, as a narrow slit. a fine vertical wire, a biprism to produce interference. By means of the biprism and slit wave-lengths may be measured with this apparatus. IMG:content-1667.jpg:[graphic] Optical Bench,