This device has a brass body, with six sides and a rectangular base. It has a door on one side and there are seven holes at the bottom of each side. On the top there is a smaller box, which served as a chimney, with three brass plates protecting the ventilation outlet. A steel tube with glass lenses protrudes from the front of the box. This is the lens. Between the lenses there is a stand with a slot on either side into which they inserted the plates that they wanted to project.
These lights were very precise scientific instruments used for all kinds of experiments about the properties of light and the fundamental laws of optics, and were found in all school science cabinets because of their educational value. This one uses an alcohol lamp as a source of light and has a gas outlet shaped like a chimney. A very varied range of experiments could be conducted with this type of apparatus: propagation of light rays, reflection and refraction phenomena, double refraction, polarization, interferences, diffraction, lens effects, spectral phenomena, etc.