Pre-R.M.S. Standard Screw Fittings for Objectives

摘要

In 1859 [1] the M.S.L. approved a standard form of objective fittings, still in use today. This was necessitated by the confusion resulting from each maker using his own preferred form of screw thread. Lenses could only be exchanged between differing makes of stand by the use of adapters, of which a wide variety was produced. The early screws were of smaller diameter than the M.S.L. standard, and when the Wenham binocular became popular after 1861, their small diameters were not sufficient to allow effective use of the binocular prism. Adapters were then produced to fit older objectives to M.S.L. nosepieces, and to fit M.S.L. objectives to older style microscopes. Little appears to have been published giving details of this muddle, and it is hoped that those given below will help to identify doubtful items. Some of the threads are only slightly different, (e.g. Dancer/P&L., and Ross/ Hartnack), and so careful measurement may save some from attempts at forced mating.