Rules as to Fractional Parts of an Inch.

British Plate.

—Pilkington’s “Glass Cutter’s Assistant” gives the following: Polished, Silvered, and Rough Cast. All fractional parts of inches will be charged as full inches, e.g., 1051⁄8 × 571⁄4 be reckoned as 106 × 58.

Rolled Plate Glass.

—Every fraction above 1⁄6 of an inch is charged as an inch, e.g.,

471⁄6×201⁄8is reckoned47×20
581⁄4×321⁄4„59×33

All Other Kinds of Window Glass.

—

1⁄4 inch and under,as1⁄4;e.g.,141⁄8×101⁄8is reckoned as141⁄4×101⁄4
5⁄16to1⁄2inch,as1⁄2;„143⁄8×105⁄16„141⁄2×101⁄2
9⁄16to3⁄4inch,as3⁄4;„149⁄16×105⁄8„143⁄4×103⁄4
13⁄16to1inch,as1;„147⁄8×1013⁄16„15 ×11

Specific Gravity.