The original prism by Joseph von Fraunhofer, Munich, with which Dr. William Hyde Wollaston discovered the dark lines in the solar spectrum, equilateral prism sides 3.0 cm length 3.5cm, some sealing wax at each end, 1801-1805.

The dark absorption lines in the spectrum of the Sun were first observed by English physicist William Hyde Wollaston in 1802. Joseph von Fraunhofer expanded on Wollaston's work and plotted these lines, designating them by brightness. His work on dark lines meant that these lines were named after him, and are still known as Fraunhofer lines. It is estimated that there are 25,000 known Fraunhofer lines in the solar spectrum.