THE POWELL & LEALAND No 1

MAKER: POWELL & LEALAND

ACCESSORIES:Large Substage Polarizer and set of Selenites

Authors: Jurriaan de Groot & Barry Sobel

Editor: Joseph Zeligs

This page contains images of a large substage polarizer which fits into the bottom of the inner ring of the substage, and a set of substage selenites fitting into the top of the substage. The polarizer is rotated by the substage rotation control while the housing with selenites, which fits into a fixed outer ring of the substage remains stationary. The large polarizer is an adapted example but nevertheless, resembles the original accessory. The set of selenites is original but has three screw holes tapped into its top. In addition, its bottom had to be restored as it had been cut short by a prior owner.

Each selenite is labeled with the letters P|A (indicating the direction of the primary axis of the crystal). The top selenite is labeled 1/4, the middle one 3/4, and the bottom one 9/4. Each selenite can be turned out of the optical axis, with any of the others or individually. Each selenite can be rotated by its individual knurled ring. The top plate of the selenite housing can accept the optical part of a condenser, such as that of the P & L High Power Achromatic condenser. This is not an RMS thread so objectives cannot be used as condensers with this fitting.