Compact arrangement for determining Planck's constant

Complete assembly of optical elements and a socket for the photoelectric cell (558 77) in a housing. With a removable cover, aperture for the entry of light from the high-pressure mercury lamp (451 15) and an observation window behind the photoelectric cell which stays closed during measurement to prevent interference from extraneous light sources.
The ray path is deflected by mirrors, so that the assembly can be kept short. Lenses (1 capacitor, 2 image lenses), slit, rectangular diaphragm and direct-vision prism in holders on a clamp rider, mounted on 2 sliding rails. One of the rails can be swivelled by means of a threaded guide such that the photoelectric cell is led through the individual spectral lines. Complete with a socket for a high-pressure mercury lamp and screened cable for connecting the measuring amplifier.