Basis of Calculations.—The calculations in the Blackburn list are based upon the picks counted by the glass when the cloth is laid upon the counter. Forty yards short stick to be taken as 39 yards long stick.
To find price for a 44-inch cloth in 45-inch loom = 66’s reed, 44 change pinion, 528 dividend, 75 yards long, 34’s/36’s—
12·25 Standard.
Add 5 per cent. loom ·61
———
12·86
Add 2-1/4 per cent. reed ·28
———
13·14
Calculate in proportion to pick 16 to 12 = 9·86
Calculate proportion length 37-1/2 to 75 = 19·72 = List price.
Double
Deduct 10 per cent. = 1·97
———
17·78 = Present price.
or from list under heading, 45-inch loom—
66 reed, 37-1/2 yards = ·822 for 1 pick.
9·86 for 12 picks.
19·72 for 75 yards.
Speeds of Shafts, Etc.
In calculating the speed of a shaft driven from another by pulleys or gearing, multiply the speed of the first shaft by the driving pulley or wheel, and divide by the driven one. A shaft makes 100 revolutions per minute and carries a 40-inch drum driving a 16-inch pulley on another shaft; the speed of the second shaft would be 250, thus:—
(100 × 40)/16 = 250.
The same rule and calculation would apply if the first shaft had carried a 40-teeth cog-wheel, and the second a 16-teeth wheel.