Unlike magnifying glasses, monocles are an actual means of correcting the
sight made up, logically, of a single lens, in just the same way as glasses
make use of one lens for each eye. It is rare to find monocles that were
made cheaply for widespread use as, one hand being necessary for their
use, they were not suitable for anyone doing a manual job.
Goldsmiths and optical craftsmen have given us magnificent examples
displaying exquisite workmanship which are now preserved in the museum.
