Long Measure
1 mile = 1760 yards = 5280 feet
1 yard = 3 feet = 36 inches
1 foot = 12 inches

Surveyor’s Measure
1 mile = 8 furlongs = 80 chains
1 furlong = 10 chains = 220 yards
1 chain = 4 rods = 22 yards = 66 feet = 100 links
1 link = 7.92 inches

Square Measure
1 square mile = 640 acres = 6400 square chains
1 acre = 10 square chains = 4840 square yards = 43,560 square feet
1 square chain = 16 square rods = 484 square yards = 4356 square feet
1 square rod = 30.25 square yards = 272.25 square feet = 625 square links
1 square yard = 9 square feet
1 square foot = 144 square inches
An acre is equal to a square, the side of which is 208.7 feet

Dry Measure
1 bushel (U.S. or Winchester struck bushel) = 1.2445 cubic foot = 2150.42 cubic inches
1 bushel = 4 pecks = 32 quarts = 64 pints
1 peck = 8 quarts = 16 pints
1 quart = 2 pints
1 heaped bushel = 1 1/4 struck bushel
1 cubic foot = 0.8036 struck bushel
1 British Imperial bushel=8 Imperial gallons=1.2837 cubic foot = 2218.19 cubic inches

Liquid Measure
1 U.S. gallon = 0.1337 cubic foot = 231 cubic inches = 4 quarts = 8 pints
1 quart = 2 pints = 8 gills
1 pint = 4 gills
1 British Imperial gallon=1.2003 U.S. gallon=277.27 cubic inches
1 cubic foot = 7.48 U.S. gallons

Circular and Angular Measure
60 seconds  = 1 minute
60 minutes = 1 degree
360 degrees = 1 circumference
57.3 degrees = 1 radian
2 pi radians = 1 circumference

Specific Gravity
The specific gravity of a substance is its weight as compared with the weight of an equal bulk of pure water
For making specific gravity determinations the temperature of the water is usually taken at 62F. when 1 cubic foot of water weighs 62.355 lbs.
Water is at its greatest density at 39.20F. or 4Centigrade.

Temperature
The following equation will be found convenient for transforming temperature from one system to another:
Let F = degrees Fahrenheit; C = degrees Centigrade; R = degrees Reamur
F–32/180=C/100=R/100

Avoirdupois or Commercial Weight
1 gross or long ton = 2240 pounds
1 net or short ton = 2000 pounds
1 pound = 16 ounces = 7000 grains
1 ounce = 16 drams = 437.5 grains

Measures of Pressure
1 psi =144 psf = 0.068 atmosphere = 2.042 in. mercury, 62  F. = 27.7 in. water,62  F. = 2.31 ft. water, 62 F
1 atmosphere = 30 inches of mercury at 62 F = 14.7 psi= 2116.3 psf = 33.95 feet of water at 62 F
1 foot of water at 62  F = 62.355 pounds per square foot = 0.433 psi
1 inch of mercury at 62 F = 1.132 foot of water = 13.58 inches of water = 0.491 psi
Column of water 12 in. high, 1 inch diameter = .341 lbs

Cubic Measure
1 cubic yard = 27 cubic feet
1 cubic foot = 1728 cubic inches
The following measures are also used for wood and masonry:
1 cord of wood = 4 X 4 X 8 feet = 128 cubic feet
1 perch of masonry = 16-1/2 X 1-1/2 X 1 foot = 24-3/4 cubic feet

Shipping Measure
For measuring entire internal capacity of a vessel:
1 register ton = 100 cubic feet
For measurement of cargo:
1 U.S. shipping ton = 40 cubic feet = 32.143 U.S. bushels = 31.16 Imperial bushels
British shipping ton = 42 cubic feet = 33.75 U.S. bushels = 32.72 Imperial bushels

Measure Used for Diameters and Areas of Electric Wires
1 circular inch = area of circle 1 inch in diameter = 0.7854 square inch
1 circular inch = 1,000,000 circular mils
1 square inch = 1.2732 circular inch = 1,273,239 circular mils
A circular mil is the area of a circle 0.001 inch in diameter

Board Measure
One foot board measure is a piece of wood 12 inches square by 1 inch thick, or 144 cubic inches. 1 cubic foot therefore equals 12 feet board measure