[OPTICS]. [CHEMISTRY]. Spectroscope by Kirchhoff and Bunsen. Brass instrument on cast iron stand, H: 38.5 cm, L: 59 cm. Designed by Gustav Kirchhoff and Robert Bunsen to observe light spectra. It consists of three arms arranged around a prism. The first - the collimator - receives the light emitted by the substance illuminated by the lamp. The light then passes through the prism and enters the second arm - the telescope - where the decomposed light is observed. A third arm - the micrometer - is used to measure the colour spectrum of the chemical elements observed. One of the lenses is broken. Late 19th century. Provenance: José Henry collection.