Case for monocular compound microscope made by J. B. Dancer.

John Benjamin Dancer (1812-1887) was one of Manchester's most important scientific instrument makers. Dancer became well known for the quality of his microscopes and particularly for selling good-quality instruments at a relatively low price. He supplied apparatus, including a travelling microscope and thermometers, to James Prescott Joule from about 1844 for his work on the mechanical equivalent of heat. Joule described Dancer's thermometers as "the first which were made in England with any pretensions to accuracy".