Before 1880 scientific instruments were made almost exclusively of four basic materials; brass, wood, iron and glass (both crown and flint). Otto Schott of Jena began to produce new forms of glass in the 1880s, which were particularly important for making thermometers and optical instruments. At the same time there was a parallel interest in the use of quartz. For electrical measuring instruments new alloys were developed, notably manganin, and platinum was introduced in electrical temperature measurement. In 1890 Guillaume's studies of Fe-Ni alloys resulted in the discovery of Invar. Discusses the ways in which new materials were used by the manufacturers of scientific instruments, and the light which this throws on the role of the instrument maker in the scientific community. -- AATA