This microscope is modeled after the design of John Cuff, the English maker of scientific instruments. It is somewhat larger in size than the Cuff microscope in the Berkeley collection. The microscope body mounts on a large, black wood chest (now riddled with worm holes). The chest has a drawer for accessories and extra lenses. The microscope is not signed.

The body tube is made of black wood with brass and copper fittings. Fine focusing is accomplished by an adjusting screw, called a Hevelius screw, after the 17th century astronomer who introduced the mechanism on telescopes that he produced.

The specimen stage is typically T-shaped with a Bonanni spring specimen holder, (named after Nicolas Bonanni, a 17th century early maker of microscopes and other instruments). A specimen forceps is mounted on the stage. A hole on the other side of the stage is designed for a fish plate or epi-illumination lens.

The objective consists of a single low-magnification lens supported by a brass fitting. The substage mirror (originally an idea of Culpeper) is mounted in the optic axis on the support shaft. The brass scroll acts as additional support for the focusing shafts as well as a carrying handle to lift the microscope out of its mounting hole in the top of the chest.

The term "Double microscope" refers to the fact that it uses two lens systems and is thus a compound microscope. Like most of the microscopes of this era, the microscope includes a third optic, or Field lens. Its design would suggest it was made after the middle of the 18th century, circa 1760-1780.

Featured 5/2004