4 mirror apparatus
A scientific instrument with four mirrors. This apparatus was designed to rejoin the light, that was divided into spectrumcoulours by a prism. It has four adjustable mirrors, diam. 8cm, on a mobile bar. On a brass stand with iron base. Total height 37cm.
In use one can place a prism in a beam of light, thereby projecting a continuously colored spectrum. The present mirrors, placed in the spectrum, can be directed to send all colors to a single spot, which spot will be white. The light decomposed by the prism has been recomposed, a possibility discovered by newton in the 17th century.