British Polished Plate Glass is made from material of a superior description, cast and rolled in the same way as rough plate, and then carefully ground down to a plane surface, and polished on both sides.
There are three qualities : -
for windows, etc.
Silvering quality for looking-glasses.
The plates kept in stock (1/4 inch thick) range as high as 100 feet superficial; larger plates, or plates exceeding 160 inches long, or 96 inches wide, are charged an extra price.
The limit of area for special thicknesses is as follows : -
Thickness (inches) ....
Maximum area in square feet .
Polished plate is used for large windows and glass doors in the best houses. It has all the advantages of other thick plate glass, and in addition is very clear and colourless, and transmits a large proportion of light. When scratched on the face it can be repolished.
Patent Quarry Rough Plate Glass is similar to the above, but the pattern is larger to imitate the quarries or small panes used in leaded quarry work.
There are two sizes, the measurement of the quarries, from point to point, both ways being as follows : -
Large size, 6 x 41/8 inches. Small „ 3 x 21/16. „
The large size is used for churches, chapels, etc.; the other for schools, staircase windows, waiting rooms, etc. etc.
In glazing, the smooth side of the glass should be inside.