Petrological Microscope and Accessories in Case, by J. Swift & Son, London, 1908

This instrument has a curved tripod foot and a circular, rotating stage with graduations marked around the rim. The nosepiece has a triple objective changer. The body-tube is mounted on a rack and pinion for coarse focusing and a graduated knob on the limb operates the fine focus. The body has ports for the etrographic accessories: tube and eyepiece slots for a compensator or quartz wedge, an analyser in a push-pull mount and a Bertrand lens in a focusing mount. There are three objectives and two eyepieces. There is also a parabolic illuminator with a central stop, an immersion paraboloid, an Abbe illuminator, Nicol prism polarizer, a camera liucida and a Wollaston camera lucida. For top illumination there is a parabolic side reflector and a vertical illuminator to attach to the nosepiece. The fitted case is mahogany and lined inside with green felt.