LUXFER PRISM PRODUCT CLASSIFIED.
The Luxfer Prism Companies manufacture
the following described grades and qualities of their product:
The different classes are technically
named and described as follows:
A prism plate composed of prism lenses
some of which are "Cut" and others "Iridian," arranged in various
forms and patterns, and called "Composite."
In this class of our product, each
piece, or prism lens, is tested by polariscope to eliminate those
lenses that may be strained in the process of manufacture; sized,
by being ground on the edges to fit exactly to within one hundredth
of an inch in the assembling; ground and polished on the receiving
face, the same as plate glass. The pieces or lenses are electro-glazed
into their frame, so as to give the greatest possible strength with
the least amount of weight and opaque area, and so as to make the
plate absolutely wind and water tight. The metal portions may be
copper, nickel or silver plated.
This term is applied to prism plates
composed of prism lenses, some of which are "Iridian," and other
This product is the same as the "Cut,"
with this exception, that the receiving surface of each prism lens
is enriched by a series of lines worked in the substance of the
prism lens, which inter-act in a peculiar manner with the prisms
of the acting surface. This product is called Iridian.
In all of the above glasses, the prism
lenses are tested on the polariscope.