Length (linear) Measurements and Conversions
1 foot = 12 inches
1 yard = 3 feet
1 rod = 16.5 feet
1 mile = 5,280 feet
1 mile = 1,760 yards
1 mile = 320 rods
1 mile = .869 nautical miles
1 nautical mile = 1.51 mile
1 kiloyard = 3000 feet
1 kiloyard = .568 mile
1 mile = 1.76 kiloyards
1 knot = 1.152 mile/hour
1 mile/hour = .8684 knots
1 mile = 8 furlongs
1 furlong = 0.125 mile
1 furlong = 660 feet
1 fathom = 6 feet
1 foot = .1667 fathom
1 hand (equine) = 4 inches = 10.16 centimeters
Surface (area) Measurements and Conversions
1 square foot = 144 square inches
1 square foot = 929 square centimeters
1 square inch = 6.451 square centimeters
1 square yard = 9 square feet
1 square yard = .836 square meters
1 square rod = 30.25 square yards
1 square rod = 272.25 square feet
1 square rod = 25.293 square meters
1 square centimeter = .155 square inches
1 square decimeter = 15.5 square inches
1 square meter = 1.196 square yards
1 square meter = 10.764 square feet
1 square kilometer = 247.1 acres
1 square kilometer = .386 square mile
1 acre = 160 square rods
1 acre = 1 rod wide & 0.5 mile long
1 acre = 43,560 square feet
1 square acre = 208.71 feet by 208.71 feet
1/2 acre = 147.58 feet wide & 147.58 feet long
1/4 square acre = 104.355 feet wide & 104.355 feet long
1 acre = 4,840 square yards
1 square acre = 69.57 yards by 69.57 yards
1 circular acre = 235.504 feet in diameter
1 hectare = 2.47105 acres
1 acre = .404686 hectares
1 square are = 10 meters by 10 meters
1 hectare = 10,000 square meters
1 square hectare = 100 meters by 100 meters
1 hectare = 107,584 square feet
1 square hectare = 328 feet by 328 feet
1 square mile = 259 hectares
1 hectare = 100 are
1 are = 100 square meters
1 are = .025 acres
1 are = 119.599 square yards
U.S. Government Land Measurements and Conversions
1 township = 36 sections
1 section = 640 acres
1 section = 1 square mile
1 quarter section = 160 acres
1 quarter section = 0.5 mile long & 0.5 mile wide
1 eighth section = 80 acres
1 eighth section = 1/2 mile long & 1/4 mile wide
1 sixteenth section = 40 acres
1 sixteenth section = 1/4 mile long & 1/4 mile wide
Surveyor’s Measurements and Conversions
1 link = 7.92 inches
1 rod = 25 links
1 chain = 4 rods
1 chain = 66 feet
1 acre = 10 square chains
1 mile = 80 chains
Volume Measurements and Conversions
1 cubic foot = 1,728 cubic inches
1 cubic yard = 27 cubic feet
Dry
1 teaspoon = .17 fluid ounces (1/6 oz.)
1 tablespoon (1/2 oz.) = 3 teaspoons (level)
1 peck = 8 quarts
1 bushel = 4 pecks
1 chaldron = 36 bushels
1 bushel grain or shelled corn = 1.25 cubic feet
1 cubic foot grain or shelled corn = .8 bushels
1 bushel ear corn = 2.5 cubic feet
1 cubic foot ear corn = .4 bushels
1 board ft. = 1" x 12" x 12" nominal dimensions
1 cord (wood) = 128 cubic feet
1 cubic yard concrete = 81 sq. ft.—4" floor
1 cubic yard concrete = 54 sq. ft.—6" floor
Liquid
1 fluid ounce = 2 tablespoons
1 cup (liquid) = 16 tablespoons (8 oz.)
1 quart = 2 pints
1 gallon = 4 quarts
1 cup = 8 fluid ounces
1 pint = 2 cups
1 pint = 16 fluid ounces
1 quart = 2 pints
1 quart = 32 fluid ounces
1 gallon = 128 ounces
1 gallon = .1337 cubic feet
1 cubic foot = 7.48 gallons
1 gallon = 231 cubic inches
1 gallon = 32 gill
1 US gallon = .8327 imperial gallons (British)
1 imperial gallon (British) = 1.201 U.S. gallons
1 gallon water (20° C)= 8.33 pounds
1 foot of water (4° C) = .4335 pounds per sq. inch
1 pound per sq. inch = 2.307 feet of water (4° C)
1 cubic foot = 62.427 pounds of water (4° C)
1 gallon = 8.33 pounds of water (4° C)
1 acre inch = 27,154 gallons liquid
1 acre foot = 325,851 gallons liquid
Velocity
1 mile per hour = 1.467 feet per second
1 mile per hour = .4469 meters per second
1 mile per hour = 1.609 kilometers per hour
1 kilometer per hour = .9114 feet per second
1 kilometer per hour = .2778 meters per second
1 kilometer per hour = .6214 miles per hour
1 meter per second = 3.281 feet per second
1 meter per second = 2.237 miles per hour
1 meter per second = 3.6 kilometers per hour
1 foot per second = .3048 meters per second
1 foot per second = .6818 miles per hour
1 foot per second = 1.0972 kilometers per hour
Flow Rate
Mass
1 short (U.S.) ton (2,000 lbs.) per day = .907 metric tons per day
1 short ton per day = 37.80 kilograms per hour
1 short ton per day = .630 kilograms per minute
1 short ton per day = 83.33 pounds per hour
1 short ton per day = 1.389 pounds per minute
1 short ton per hour = 33.33 pounds per minute
1 short ton per hour = 15.12 kilograms per minute
1 metric ton (2,205 lbs.) per day = 1.102 short tons per day
1 metric ton per day = 41.67 kilograms per hour
1 metric ton per day = .694 kilograms per minute
1 metric ton per day = 91.86 pounds per hour
1 metric ton per day = 1.531 pounds per minute
1 metric ton per hour = 36.74 pounds per minute
1 metric ton per hour = 16.67 kilograms per minute
VOLUME
1 cubic foot per hour = .0283 cubic meter per hour
1 cubic meter per hour = 35.315 cubic feet per hour
1 U.S. gallon per hour = 3.785 liters per hour
1 gallon per hour = 3.209 cubic feet per day
1 gallon per hour = 1,171 cubic feet per year
1 gallon per hour = 90.84 liters per day
1 gallon per hour = 33,157 liters per year
1 gallon per hour = 19.97 imperial gallons per day
1 gallon per hour = 7,289 imperial gallons per year
1 liter per hour = .264 gallons per hour
1 liter per hour = .8474 cubic feet per day
1 liter per hour = 309.3 cubic feet per year
1 liter per hour = 6.298 U.S. gallons per day
1 liter per hour = 2,299 U.S. gallons per year
1 liter per hour = 5.28 imperial gallons per day
1 liter per hour = 1,927 imperial gallons per year
1 acre foot per day = 325,851 gallons per day
1 acre foot per day = 13,577 gallons per hour
1 acre foot per day = 266 gallons per minute
1 acre foot per day = 3.77 gallons per second
1 acre foot per day = 1815.00 cubic feet per hour
1 acre foot per day = 30.250 cubic feet per minute
1 acre foot per day = .504 cubic feet per second
1 acre foot per day = 67.222 cubic yards per hour
1 acre foot per day = 1.120 cubic yards per minute
1 acre foot per day = 51.40 cubic meters per hour
1 acre foot per day = .857 cubic meters per minute
1 acre foot per hour = 7,820,434 gallons per day
1 acre foot per hour = 325,851 gallons per hour
1 acre foot per hour = 5,430.86 gallons per minute
1 acre foot per hour = 90.51 gallons per second
1 acre foot per hour = 43,600 cubic feet per hour
1 acre foot per hour = 726.000 cubic feet per minute
1 acre foot per hour = 12.100 cubic feet per second
1 acre foot per hour = 1,613 cubic yards per hour
1 acre foot per hour = 26,889 cubic yards per minute
1 acre foot per hour = .448 cubic yards per second
1 acre foot per hour = 1,233.48 cubic meters per hour
1 acre foot per hour = 20.56 cubic meters per minute
1 acre foot per hour = .343 cubic meters per second
1 acre inch per hour = 27,154 gallons per day
1 acre inch per hour = 1131.43 gallons per hour
1 acre inch per hour = 18.857 gallons per minute
1 acre inch per hour = .314 gallons per second
1 acre inch per hour = 60.50 cubic feet per minute
1 acre inch per hour = 1.008 cubic feet per second
1 acre inch per hour = 2.241 cubic yards per minute
1 acre inch per hour = .037 cubic yards per second
1 acre inch per hour = 1.713 cubic meters per minute
1 acre inch per hour = .029 cubic meters per second
1 hectare meter per day = 8.107 acre feet per day
1 hectare meter per day = 110,072 gallons per hour
1 hectare meter per day = .338 acre feet per hour
1 hectare meter per day = 97.29 acre inches per day
1 hectare meter per day = 14,714 cubic feet per day
1 hectare meter per day = 416.67 cubic meters per day
Circle & Sphere (area) Measurements and Conversions
Diameter of a circle = circumference x .31831
Circumference of a circle = diameter x 3.1416
Area of a circle = diameter x diameter x .7854
Surface of a ball = diameter x diameter x 3.1416
Doubling the diameter of a pipe increases it's capacity 4 times
Apothecaries’ Weight (1 pound = 12 ounces) Measurements and Conversions
1 pound = 12 ounces
1 ounce = 8 drams
1 dram = 3 scruples
1 scruple = 20 grains
Avoirdupois’ Weight (1 pound = 16 ounces) Measurements and Conversions
1 pound = 16 ounces
1 pound = 256 drams
1 quarter = 25 pounds
1 hundredweight (cwt) = 100 pounds
1 ton = 2000 pounds
Ton (weight) Measurements and Conversions
1 short ton (U.S. ton) = 2000 lbs.
1 short tone = 907 kgs.
1 long ton (imperial ton or shipping ton) = 2,240 lbs.
1 long ton = 1,016 kgs.
1 metric ton (tonne) = 2,204.60 lbs.
1 metric ton = 1,000 kgs.
1 long ton = 1.120 short tons
1 long ton = 1.0160573 metric tons
1 metric ton = 1.10231136 short tons
1 metric ton = 0.9841964 long tons
1 short ton = 0.8928571 long tons
1 short ton = 0.9071847 metric tons
Speed Measurements and Conversions
1 kilometer per hour = .6214 miles per hour
1 mile per hour = 1.609 kilometers per hour
1 meter per second = 2.24 miles per hour
1 mile per hour = .447 meters per second
1 knot = 1.15 miles per hour
1 meter per second = 3.6 kilometers per hour
Application Measurements and Conversions
phosphorus (P) x 2.29 = P2O5
P2O5 x.44 = phosphorus (P)
potash (K) x 1.2 = K2O
K2O x .83 = potash (K)
1 short ton per acre = 2.24 metric tons per hectare
1 metric ton per hectare = .446 short tons per acre
Areas or Surfaces
1 acre = 43,560 square feet = 4,840 square yards = 0.405 hectare
1 are = 119.599 square yards = 0.025 acre
1 bolt length = 100 yards
1 bolt width = 45 or 60 inches
1 hectare = 2.471 acres
1 mile square = 1 section (of land)
1 square (building) = 100 square feet
1 square centimeter = 0.155 square inch
1 square decimeter = 15.500 square inches
1 square foot = 929.030 square centimeters
1 square inch = 6.4516 square centimeters
1 square kilometer = 247.104 acres = 0.386 square mile
1 square meter = 1.196 square yards = 10.764 square feet
1 square mile = 258.999 hectares
1 square millimeter = 0.002 square inch
1 square rod, square pole, or square perch = 25.293 square meters
1 square yard = 0.836 square meter
10,000 square centimeters = 1 square meter = 1,000,000 square millimeters
100 acres = 40.5 hectare = 405,000 square meters
100 hectares = 1 square kilometer = 1,000,000 square meters
100 square meters = 1 are
100 square millimeters = 1 square centimeter
144 square inches = 1 square foot
160 square rods = 1 acre = 4,840 square yards = 43,560 square feet
30 1/4 square yards = 1 square rod = 272 1/4 square feet
40 square rods = 1 rood
6 miles square = 1 township = 36 sections = 36 square miles
640 acres = 1 square mile
9 square feet = 1 square yard = 1,296 square inches
Capacities or Volumes
1 barrel liquid = 31 to 42 gallons
1 barrel, standard, cranberry = 5,826 cubic inches = 86 45/64 dry quarts = 2.709 bushels, struck measure
1 barrel, standard, for fruits, vegetables, and other dry commodities except dry cranberries = 7,056 cubic inches = 105 dry quarts = 3.281 bushels, struck measure
1 board foot = a foot-square board 1 inch thick
1 bushel (British Imperial) (struck measure) = 1.032 U.S. bushels struck measure = 2,219.36 cubic inches
1 bushel (U.S.) (struck measure) = 2,150.42 cubic inches = 35.239 liters
1 bushel, heaped (U.S.) = 2,747.715 cubic inches = 1.278 bushels, struck measure
1 cord firewood = 128 cubic feet
1 cubic centimeter = 0.061 cubic inch
1 cubic decimeter = 61.024 cubic inches
1 cubic foot = 7.481 gallons = 28.317 cubic decimeters
1 cubic inch = 0.554 fluid ounce = 4.433 fluid drams = 16.387 cubic centimeters
1 cubic meter = 1.308 cubic yards
1 cubic yard = 0.765 cubic meter
1 cup, measuring = 8 fluid ounces = 1/2 liquid pint
1 deciliter = 2.642 gallons = 1.135 pecks
1 dram, fluid (British) = 0.961 U.S. fluid dram = 0.217 cubic inch = 3.552 milliliters
1 gallon (British Imperial) = 277.42 cubic inches = 1.201 U.S. gallons = 4.546 liters = 160 British fluid ounces
1 gallon (U.S.) = 231 cubic inches = 3.785 liters = 0.833 British gallon = 128 U.S. fluid ounces
1 gill = 7.219 cubic inches = 4 fluid ounces = 0.118 liter
1 hectoliter = 26.418 gallons = 2.838 bushels
1 liter = 1.057 liquid quarts = 0.908 dry quart = 61.025 cubic inches
1 milliliter = 0.271 fluid dram = 16.231 minims = 0.061 cubic inch
1 ounce liquid (U.S.) = 1.805 cubic inches = 29.573 milliliters = 1.041 British fluid ounces
1 ounce, fluid (British) = 0.961 U.S. fluid ounce = 1.734 cubic inches = 28.412 milliliters
1 peck = 8.810 liters
1 pint, dry = 33.600 cubic inches = 0.551 liter
1 pint, liquid = 28.875 cubic inches = 0.473 liter
1 quart (British) = 69.354 cubic inches = 1.032 U.S. dry quarts = 1.201 U.S. liquid quarts
1 quart dry (U.S.) = 67.201 cubic inches = 1.01 liters = 0.969 British quart
1 quart liquid (U.S.) = 57.75 cubic inches = 0.946 liter = 0.833 British quart
1 tablespoon = 3 teaspoons = 4 fluid drams = 1/2 fluid ounce
1 teaspoon = 1/3 tablespoon = 1 1/3 fluid drams
Cubic Measure
1 cubic foot = 1,728 cubic inches
1,000 cubic centimeters = 1 cubic decimeter = 1,000,000 cubic millimeters
1,000 cubic decimeters = 1 cubic meter = 1 stere = 1,000,000 cubic centimeters = 1,000,000,000 cubic millimeters
1,000 cubic millimeters = 1 cubic centimeter
27 cubic feet = 1 cubic yard
Lengths
1 angstrom = 0.1 nanometer = 0.0001 micrometer = 0.0000001 millimeter = .000000004 inch
1 cable's length = 120 fathoms = 720 feet = 219 meters
1 centimeter = 0.3937 inch
1 chain (engineers) = 100 feet = 30.48 meters
1 chain (Gunter's or surveyor's) = 66 feet = 20.1168 meters
1 decimeter = 3.937 inches
1 degree (geographical) = 364,566.929 feet = 69.047 miles = 111.123 kilometers
1 degree of latitude = 68.708 miles at equator = 69.403 miles at poles
1 degree of longitude = 69,171 miles at equator
1 decameter = 32.808 feet
1 fathom = 6 feet = 1.8288 meters
1 foot = 0.3048 meters
1 furlong = 10 chains (surveyors) = 660 feet = 1/8 statute mile = 201.168 meters
1 hand = 4 inches
1 inch = 2.54 centimeters
1 international nautical mile = 1.852 kilometers = 1.150779 survey miles = 6,076.11549 feet
1 kilometer = 0.621 mile = 3,281.5 feet
1 league = 3 survey miles = 4.828 kilometers
1 link (Gunter's or surveyor's) = 7.92 inches = 0.201 meter
1 link engineers = 1 foot = 0.305 meter
1 meter = 39.37 inches = 1.094 yards
1 micrometer = 0.001 millimeter = 0.00003937 inch
1 mil = 0.001 inch = 0.0254 millimeter
1 mile = 5,280 feet = 1.609 kilometers
1 millimeter = 0.03937 inch
1 nanometer = 0.001 micrometer = 0.00000003937 inch
1 pica = 12 points
1 point = 0.013837 inch = 0.351 millimeter
1 rod, pole, or perch = 16 1/2 feet = 5.029 meters
1 yard = 0.9144 meter
100 fathoms = 1 cable length
12 inches = 1 foot
3 feet = 1 yard
3 miles = 1 league = 5,280 yards = 15,840 feet
4 rods = 1 chain 40 rods = 1 furlong = 220 yards = 660 feet
5 1/2 yards = 1 rod, pole, or perch (16 1/2 feet)
6076.11549 feet = 1 International Nautical Mile
8 furlongs = 1 statute mile = 1,760 yards = 5,280 feet
Surveyor's Chain Measure
100 links = 1 chain = 4 rods = 66 feet
7.92 inches = 1 link
80 chains = 1 survey mile = 320 rods = 5,280 feet
Temperature Conversion
From °F to °C: subtract 32, multiply by 5, divide by 9
From °C to °F: multiple by 9, divide by 5, add 32
Weights or Masses
1 assay ton = 29.167 grams
1 bale = 500 pounds in U.S. = 750 pounds in Egypt
1 carat = 200 milligrams = 3.086 grains
1 dram avoirdupois = 27 11/32 or 27.344 grains = 1.772 grams
1 gamma = 1 microgram
1 grain = 64.799 milligrams
1 gram = 15.432 grains = 0.035 ounce, avoirdupois
1 hundredweight, gross or long = 112 pounds = 50.802 kilograms
1 hundredweight, net or short = 100 pounds = 45.359 kilograms
1 kilogram = 2.205 pounds
1 microgram = 0.000001 gram
1 milligram = 0.015 grain
1 ounce, avoirdupois = 437.5 grains = 0.911 troy ounce = 28.350 grams
1 ounce, troy = 480 grains = 1.097 avoirdupois ounces = 31.103 grams
1 pennyweight = 1.555 grams
1 pound, avoirdupois = 7,000 grains = 1.215 troy pounds = 453.59237 grams
1 pound, troy = 5,760 grains = 0.823 avoirdupois pound = 373.242 grams
1 ton, gross or long = 2,240 pounds = 1.12 net tons = 1.016 metric tons
1 ton, metric = 2,204.623 pounds = 0.984 gross ton = 1.102 net tons
1 ton, net or short = 2,000 pounds = 0.893 gross ton = 0.907 metric ton
1,000 kilograms = 1 metric ton
10 centigrams = 1 decigram = 100 milligrams
10 decigrams = 1 gram = 1,000 milligrams
10 dekagrams = 1 hectogram = 100 grams
10 grams = 1 dekagram
10 hectograms = 1 kilogram = 1,000 grams
10 milligrams = 1 centigram
Length and Area
Length 12 lines = 1 inch
12 inches = 1 foot
3 feet = 1 yard
1760 yards = 1 mile
36 inches = 1 yard
440 yards = quarter mile
880 yards = half mile 100 links = 1 chain
10 chains = 1 furlong
8 furlongs = 1 mile
4 inches = 1 hand
22 yards = 1 chain
5.5 yards = 1 rod, pole or perch
40 poles = 1 furlong
The units in common use were inches, feet, yards and miles. We all had to know our twelve times table! An inch is the width of a thumb, a foot is the length of a foot (!) and a yard is a single stride, all for a large man. My thumb is 3/4 inch across, my foot is 11 inches and my stride is 2 feet.
The foot has been used for over a thousand years, the inch since medieval times, and the yard in the reign of Henry I (1100-1137) as within a tenth of an inch of the modern yard.
The inch is defined as exactly 2.54 centimetres. This means that the Imperial units of length are based on the metric system!
A mile is derived from "mille", Latin for thousand, since a mile is a thousand Roman double paces, from left foot to left foot, about 5 feet, which would make 5000 feet. The mile is 5280 feet. In the past every part of England had its own mile, up to 2880 yards (it is now 1760 yards). In ireland, the mile was 2240 yards well into the 20C.
A chain is the length of a cricket pitch. It has been used since 1620.
Medieval ploughing was done with oxen, up to 4 pairs at a time. The ploughman handled the plough. His boy controlled the oxen using a stick, which had to be long enough to reach all the oxen. This was the rod, pole or perch. It was an obvious implement to measure the fields, such as 4 poles to the chain. The perch was used in the reign of Henry II (1154-1189), the pole since the 16C, and the rod since 1450.
A furlong is a "furrow long" or length of a mediaeval field. It is used for the lengths of some horse races.
Hands are used to measure horses. You measure from the ground to the withers of the horse (its shoulder) since it won't keep its head still. 3 hands = 1 foot (which sounds slightly odd).
A line has been used since the 17C. It is used by botanists to describe the size of plants (which must be very small!) It is not common (in fact, I had never heard of it until I started researching this site!)
A thou is a colloquial term for a thousandth of an inch. It has been used since Victorian times.
Area 4840 square yards = 1 acre
1 furlong x 1 chain = 1 acre
1210 square yards = 1 rood
1 furlong x 1 pole = 1 rood
4 roods = 1 acre 144 square inches = 1 square foot
9 square feet = 1 square yard
640 acres = 1 square mile
Rods, poles, perches and roods were all rather confused. They could all be a measure of length (5.5 yards). Rods, poles and erches could also be a measure of area (5.5 yards square, or 30.25 square yards). So a 10 perch allotment would be 5.5 yards wide by 55 yards long. A rood could be a measure of area (1210 square yards). The dictionary also cheerfully states that this could vary round the country!
While I am not giving metric tables (they're BORING), a hectare is 10,000 square metres (or a hundredth of a square kilometre).
Older measures
There are some measures that were not in our "tables" which we had to learn as children, because they had fallen into disuse (although I have never heard of anyone using rods, poles or perches!) However, you do read about them. Many imperial measures of length were originally taken from parts of the body, sometimes obviously, such as hands or feet. But then at some time a standard
length was decided on, and used by everyone. These older measurements, however, are not so precise.
A span is the length from your little finger to your thumb if you stretch your fingers, or 9 inches (23 cm).
The cubit is the earliest unit of length, used in Egypt in the 3rd Dynasty (2800-2300 BC). It is the length of the arm from the elbow to the tip of the middle finger. The English cubit is 18 inches long (46 cms), but the Romans, Egyptians and Hebrews all had different lengths. Cubits are used in the Bible. The ark was 300 cubits long. An ell is derived from "elbow". It started off similar to the cubit (see above), but the English ell was 45 inches long (115 cm). Other countries had different lengths for their ell. There was an old saying "Give him an inch and he'll take an ell", which got changed to "Give him an inch and he'll take a mile". A cloth-yard was used to measure cloth. It is 37 inches long (94 cm), which is an inch longer than an ordinary yard. A cloth-yard shaft was an arrow a cloth-yard long. A league is another measure that varies by country. In England, it is taken to be 3 miles. Tennyson wrote of the Charge of the Light Brigade:
"Half a league, half a league, half a league onwards
Into the valley of death rode the six hundred."
In fairy tales, there were seven league boots, which would carry you 7 leagues (10.5 miles) in one stride! Jules Verne wrote a book about a submarine, called "40,000 Leagues under the Sea" (this refers to how far they travelled, not how deep they were!). A hide was enough land to support a house-hold, usually between 60-120 acres (24-48 hectares). A hide of good land was smaller than that of poor quality. Hides are used in the Doomsday Book. An acre is 4840 square yards (see above) and is a conventional measure of area. It was defined in the time of Edward I (1272-1307) and was supposed to be the area that a yoke of oxen could plough is a day. Acre is derived from the Latin for field. But the common field system of medieval times in Britain was ten acres. An acre is a furlong (furrow length) long and a chain wide. In fact, an archaic word for furlong was "acre-length" and for chain "acre-width". The Scottish and Irish used to have different values for their acres. The Scottish acre was 6150.4 square yards and the Irish acre was 7840 square yards.
Some archaeologists have deduced a megalithic yard from the statistical study of prehistoric stone circles, which they estimate to be 2.72 feet. It seems strange that pre-historic man had such a consistent measure, when in the past the mile was defined differently in different parts of England! Surely, they just measured out their circles with paces, which tend to be that length! It doesn't have to be a formal unit.
Units of Measure
Acre - The (English) acre is a unit of area equal to 43,560 square feet, or 10 square chains, or 160 square poles. It derives from a plowing area that is 4 poles wide and a furlong (40 poles) long. A square mile is 640 acres. The Scottish acre is 1.27 English acres. The Irish acre is 1.6 English acres.
Arpent - Unit of length and area used in France, Louisiana, and Canada. As a unit of length, approximately 191.8 feet (180 old French 'pied', or foot). The (square) arpent is a unit of area, approximately .845 acres, or 36,802 square feet.
Chain - Unit of length usually understood to be Gunter's chain, but possibly variant by locale. Chains equal to 2 poles (one half the standard length) are found in Virginia. The name comes from the heavy metal chain of 100 links that was used by surveyors to measure property bounds.
Colpa - Old Irish measure of land equal to that which can support a horse or cow for a year. Approximately an Irish acre of good land.
Engineer's Chain - A 100 foot chain containing 100 links of one foot apiece.
Furlong - Unit of length equal to 40 poles (220 yards). Its name derives from "furrow long", the length of a furrow. See Gunter's chain.
Gunter's Chain - Unit of length equal to 66 feet, or 4 poles. This unit was apparently defined as one tenth of a furlong, a common unit of length in the old days. The mile was redefined from the old Roman value of 5000 feet to 5280 feet in order to be an even multiple of furlongs. A mile is 80 chains.
Hectare - Metric unit of area equal to 10,000 square meters, or 2.471 acres, or 107,639 square feet.
Hide - Old English unit of area usually equal to 120 acres.
Labor - The labor is a unit of area used in Mexico and Texas. In Texas it equals 177.14 acres (or 1 million square varas).
League (legua) - Unit of area used in the southwest U.S., equal to 25 labors, or 4428 acres (Texas), or 4439 acres (California). Also, a unit of length-- approximately three miles.
Link - Unit of length equal to 1/100 chain (7.92 inches).
Morgen - Unit of area equal to about .6309 acres. It was used in Germany, Holland and South Africa, and was derived from the German word Morgen ("morning"). It represented the amount of land that could be plowed in a morning.
Perch - See pole .
Point - A point of the compass. There are four cardinal points (North, South, East, West), and 28 others yielding 32 points of 11.25 degrees each. A survey line's direction could be described as a compass point, as in "NNE" (north northeast). To improve precision, the points would be further subdivided into halves or quarters as necessary, for example, "NE by North, one quarter point North". In some areas, "and by" meant one half point, as in "NE and by North".
Pole - Unit of length and area. Also known as a perch or rod. As a unit of length, equal to 16.5 feet. A mile is 320 poles. As a unit of area, equal to a square with sides one pole long. An acre is 160 square poles. It was common to see an area referred to as "87 acres, 112 poles", meaning 87 and 112/160 acres.
Pueblo - A Spanish grant of less than 1000 acres.
Rancho - A Spanish grant of more than 1000 acres.
Rod - See pole
Rood - Unit of area usually equal to 1/4 acre.
Vara - Unit of length (the "Spanish yard") used in the U.S. southwest. The vara is used throughout the Spanish speaking world and has values around 33 inches, depending on locale. The legal value in Texas was set to 33 1/3 inches early in the 1900's.
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Standard Surveying Terms
Aliquot - The description of fractional section ownership used in the U.S. public land states. A parcel is generally identified by its section, township, and range. The aliquot specifies its precise location within the section, for example, the northwest quarter of the southeast quarter.
Benchmark - A survey mark made on a monument having a known location and elevation, serving as a reference point for surveying.
Call - Any feature, landmark, or measurement called out in a survey. For example, "two white oaks next to the creek" is a call.
Chain carrier - An assistant to the surveyor, the chain carriers moved the surveying chain from one location to another under the direction of the surveyor. This was a position of some responsibility, and the chain carriers took an oath as "sworn chain carriers" that they would do their job properly.
Condition - See Conditional line.
Conditional line - An agreed line between neighbors that has not been surveyed, or which has been surveyed but not granted.
Corner - The beginning or end point of any survey line. The term corner does not imply the property was in any way square.
Declination - The difference between magnetic north and geographic (true) north. Surveyors used a compass to determine the direction of survey lines. Compasses point to magnetic north, rather than true north. This declination error is measured in degrees, and can range from a few degrees to ten degrees or more. Surveyors may have been instructed to correct their surveys by a particular declination value. The value of declination at any point on the earth is constantly changing because the location of magnetic north is drifting. More information about historical values of declination is available.
First station - See Point of Beginning
Gore - A thin triangular piece of land, the boundaries of which are defined by surveys of adjacent properties. Loosely, an overlap or gap between properties. See also strip.
Landmark - A survey mark made on a 'permanent' feature of the land such as a tree, pile of stones, etc.
Line Tree - Any tree that is on a property line, specifically one that is also a corner to another property.
Merestone - A stone that marks a boundary. See monument.
Monument - A permanently placed survey marker such as a stone shaft sunk into the ground.
Out - An 'out' was ten chains. When counting out long lines, the chain carriers would put a stake at the end of a chain, move the chain and put a stake at the end, and so on until they ran "out" of ten stakes.
Point of Beginning - The starting point of the survey
Plat - A drawing of a parcel of land.
Range - In the U.S. public land surveying system, a north-south column of townships, identified as being east or west of a reference longitudinal meridian, for example, Range 3 West. See township.
Searles Spiral - A surveying technique used by railroad surveyors in the the late 1800s and early 1900s whereby they approximate a spiral by use of multiple curved segments.
Section - In the U.S. public land surveying system, an area one mile square. See aliquot.
Strip - A rectangular piece of land adjoining a parcel, created when a resurvey turns up a tiny bit larger than the original survey. The difference is accounted for by temperature or other effects on measuring chains. See also gore.
Township - In the U.S. public land surveying system, an area six miles square, containing 36 sections. The townships are organized in rows and are identified with respect to a reference latitudinal baseline, for example, Township 13 North. See range.
Witness Tree - Generally used in the U.S. public land states, this refers to the trees close to a section corner. The surveyor blazed them and noted their position relative to the corner in his notebook. Witness trees are used as evidence for the corner location.
--------------------------------------------------------------------------------
Surveyors' Slang
Surveying, like any profession, has its special terms and slang. Some are just humorous, some help distinguish similar sounds (e.g. eleven and seven), and some are just plain strange!
Balls - Slang for numeric .00, as in 4-balls (4.00)
Beep - Verb. To use a magnetic detector to look for iron pipe, etc.
Burn - See shoot
Double nickel - Slang for .55, as in 6-double nickel (6.55)
EDM - Electronic Distance Measurement device, the instrument used by modern surveyors that replaces the use of measurement chains. It determines distance by measuring the time it takes for light to reflect off a prism on top of a rod.
Ginney - A wooden dowel 6-9 inches in length with a sharpened end. Set in the ground to mark survey points.
Glass - The EDM prism.
Gun - See EDM
Hours - Degrees
Hub and Tack - A 2" by 2" stake that is set in the ground and that contains a nail ("tack") that precisely marks the point being set.
Legs - Tripod
Pogo - Prism pole
Punk - See railroad.
Railroad - Slang for eleven, as in 42-railroad (42.11)
Rodman - The person holding the rod with the EDM prism. This person is the modern version of a chain carrier or chain man.
Shoot - Measure distance with an EDM
Spike - Usually a 60 penny nail used to mark survey points in hard ground.
Top - Slang for eleven. See railroad.
Zero - Zero degrees, minutes, and seconds. A perfect zero.
--------------------------------------------------------------------------------
Water Terms
Bank - Edge of a stream.
Bottom - Land along a river.
Branch - Small stream.
Brook - Small stream.
Creek - Small stream.
Drain - Small dry stream or gully.
Drean - See drain.
Ford - Shallow part of a stream or river where one could cross.
Fork - Meeting point of two streams. "In the fork of" means between two branches.
Gut - A narrow passage between hills. A stream in such a passage. A drain.
Head - The source of a stream.
Headwaters - The smallest streams that combine to small a larger stream.
Lower - Toward the mouth of a stream. Further down along its course. Opposite of upper.
Meander - "with the meanders of the stream" means the survey line follows the twists and turns of the stream.
Mouth - The place where a stream enters another, larger stream.
Narrows - Narrow part of a stream.
River - Large stream.
Run - Small stream.
Shoal - Shallows.
Spring - A pool or other source of water that feeds a stream.
Swamp - In the southeast, a stream, particularly one that has has swampy parts. A marsh.
Upper - Toward the head of a stream. Further up along its course. Opposite of lower.
Waters ("watters") of - In the drainage of.
--------------------------------------------------------------------------------
Trees
Ash - has tough, straight-grained wood
Aspen - a type of poplar
Basswood - see linden
Beech - smooth gray bark and small edible nuts
Birch, (burch) -
Black gum - see tupelo
Blackjack - a type of small oak
Black oak -
Black walnut -
Box oak -
Buckeye -
Cedar -
Cherry -
Chestnut - American chestnut has been virtually destroyed by blight.
Chestnut oak - has leaves resembling a chestnut
Cottonwood -
Dogwood -
Elm -
Gum - subtypes: black, sweet
Hackberry - has cherry-like fruit
Hickory, hiccory, hickry - has edible nuts and hard wood
Hornbeam - has hard, heavy wood
Ironwood - see hornbeam
Laurel -
Live oak -
Lowerwood - transcription error for sourwood
Maple, (maypole)
Mountain birch -
Oak, (oake) - subtypes: black, box, chestnut, live, pin, post, red, scrub, Spanish, swamp white, white
Pawpaw -
Persimmon - has plum-like fruit
Pine -
Pin oak -
Pohiccory - see hickory
Poplar, popular -
Post oak - wood used for posts
Red oak -
Sapling, (saplin) - young tree
Sassafras - bark used in medicines and beverages
Scrub oak - usually found in dry, rocky soil
Sour gum - see tupelo
Sourwood - sorrel tree
Spanish oak -
Spruce -
Sugar tree - sugar maple
Swamp white oak - heavy, hard wood used in shipbuilding, furniture, etc.
Sweet gum - hard reddish brown wood used for furniture
Sycamore -
Tupelo -
Walnut - black
White oak -
Units of Measurement
Area
...
Did you know that
the hunting area of a pack of wolves is 1 000 m2?
the surface area of a dragonfly's wings is 1 380 mm2?
the largest leaves are found on the Abcasia maerorrhiza plant of East Malaysia; each leaf has a surface area of 317 m2?
The abbreviations used by scientists for the units of area are as folloWS
km2
square kilometre
ha
hectare
m2
square metre
cm2
square centimetre
mm2
square millimetre
The relationship between these units of area is:
Unit of Area
Relationship
1 km2 = 1 000 000 m2
1 ha = 10 000 m2
1 m2 = 10 000 cm2
1 cm2 = 100 mm2
Length
...
Did you know that
a blue whale is 33,6 m long?
a giant squid is 17 m long?
the eucalyptus plant can reach 132 m in height?
the tallest man is 2,72 m in height?
the deepest roots reach 120 m into the soil?
The abbreviations used by scientists for the units of length are as follows:
Abbreviation
Length
km
kilometre
m
metre
cm
centimetre
mm
millimetre
µm
micrometre
The relationship between these units of length is:
Unit of Length
Relationship
1 km = 1000 m
1 m = 100 cm
1 cm = 10 mm
1mm = 1000 µm
Load
...
The load is the amount of mass carried by a certain unit of area. For example, the load on an insect's wings is measured as the body mass of the insect divided by the surface area of its wings.
body mass : wing surface area = load in mg/mm2
Mass
...
The most massive living organism on Earth is a plant. It is called the giant sequoia which can have a mass of 2500 tonnes, including its roots?
A housefly has a mass of 12mg?
The dolphin has a mass of around 40kg?
Abbreviation
Units of Mass
tonnes
tonnes
kg
kilogramme
g
gramme
mg
milligramme
Speed
...
Speed measures the movement of something in a certain time interval. For example, we can measure the speed of the movement of an animal in
metres per hour = m/h
or kilometres per hour = km/h
For other measurements, such as the rate of your heartbeat, we would use the measurement
beats per minute = beats/min
Or, for the movement of an insect's wings, we would study the
beats per second = beats/s
The cheetah has a maximum speed of 115 km/h.
The snail slithers along at a maximum speed of 0,83 m/min.
The tuna swims at a maximum speed of 80 km/h.
The sap in a tree moves at a speed of 100cm/h.
Time
...
The abbreviations for the units of time are:
Abbreviation
Units of Time
h
hour
min
minute
s
seconds
Remember that:
60 minutes = 1 hour
60 seconds = 1 minute
so 1 min 30 s = 1,5 min (not 1,30 min)
Volume
...
Did you know that
an elephant needs to drink between between 70dm3 and 90dm3 of water each day?
a man with a mass of 70kg has 5,645dm3 of blood in his body?
the human lungs can hold a maximum of 6dm3 of air?
Abbreviation
Area
m3
cubic metre
dm3
cubic decimetre
cm3
cubic centimetre
mm3
cubic millimetre
The relationship between these units of area is:
...
Unit of Volume
Relationship
1 cm3 = 1 000 m3
1 dm3 = 1 000 cm3
(note that 1 dm3 used to be called 1 litre)
Measurement Facts
60 drops = 1 teaspoon
3 teaspoons = 1 tablespoon
2 tablespoons = 1 fl. oz.
8 tablespoons = 1/2 cup
Juice of 1 orange = 5-6 tsp 5 large eggs = 1 cup 2 tablespoons butter = 1 oz
Temperature
...
Temperature is a measure of the hotness or coldness of an object.
How can we measure temperature?
...
By touch
...
Your body is a temperature measuring instrument. By simply touching an object, you can tell if it is hot or cold. However, this does not tell you how hot or cold it is.
Using a thermometer
...
Scientists are always interested in measuring things, so it is not surprising that a devise was invented to measure temperature. It is called a thermometer.
The measurement of temperature we use in Europe is based on the centigrade scale.
0°C = the freezing point of water
100°C = the boiling point of water
Thermometers
The inventor of the first thermometer is thought to have been a very famous Italian scientist called Galileo Galilei. Galileo was born in 1564. His first thermometer was a very simple one. Like most of the thermometers in use today, it worked on the idea that as things get hot they expand and as they cool down they contract.
Galileo's thermometer was "open" at one end which made it sensitive to air pressure changes. The first "closed" thermometer was invented by Ferdinand II Grand Duke of Tuscany in 1641. He invented the alcohol thermometer. His invention started a thermometer making tradition in Florence. The thermometers made in Florence in the 17th century were so good that some of them were still being used 200 years later.
Alcohol is a good liquid to use in a thermometer because it remains a liquid over most of the normal temperatures found on the Earth's surface. You will sometimes use alcohol thermometers in school. The alcohol is often coloured red or green in these thermometers so that the liquid can be seen more easily. However, alcohol is not much use at hot temperatures because it boils at about 80°C, which is quite a low temperature.
For higher temperatures a different liquid is needed. The Florentines experimented with mercury which boils at a much higher temperature than alcohol, at 357°C. The main problem with mercury thermometers is that they need a very fine tube, so it is difficult to see the level of the liquid inside them.
Now that accurate thermometers had been made to measure the temperature, scientists discussed what units they should use to measure temperature in. It is not surprising that everyone had their own particular ideas about this. By the 18th century as many as 35 different temperature scales had been developed. Fortunately, scientists like to standardise their measurements and use only one type of unit to measure things by. All we have left today are two scales of temperature in everyday use, (Fahrenheit and Celcius), and one scale used by many scientists, especially physicists, who deal with really low temperatures (Kelvin).
The Fahrenheit scale
...
The Fahrenheit scale is named after Gabriel Daniel Fahrenheit, a Dutch instrument maker who was famous for the quality of his thermometers. In 1714 he put forward a temperature scale which was based on the human body temperature. Originally, human body temperature was 100 on the Fahrenheit scale, but it has since been adjusted to 99°F.
Fahrenheit temperatures are written like this: 32°F
The Fahrenheit scale is still used in a few countries, such as the USA, but scientists all over the world usually use the other two scales.
Johnny's Fact File No.3
The normal body temperature is 37°C.
One of the lowest recorded temperatures on Earth was -89,2°C at Vostok, Antarctica, on 21 July 1983.
One of the highest recorded temperatures on Earth was 58°C at Al Aziziyah, Libya, on 13 September 1922.
The Centigrade scale
...
In 1740, Anders Celcius, a Swedish astronomer, proposed a temperature scale which was based upon the freezing point of pure water (which he set at O degrees) and the boiling point of pure water (which he set at 100 degrees). He divided the temperatures in between 0 and 100 degrees into 100 equal units. This explains why the Celcius scale is also called the Centigrade scale (centi - grade = 100 parts). Celcius temperatures are written like this: 37°C
Centigrade-Fahrenheit Conversion
...
The two scales, Fahrenheit and Celcius naturally give different numerical results for the same measurement,
Measurement
Fahrenheit
Celcius
Freezing point of water 32
0
Boiling point of water 212
100
Body temperature 99
37
To convert Fahrenheit to Celcius:
X°F =
(X-32) x 5
9
or X minus 32, multiplied by five and then divided by nine.
To convert Celcius to Fahrenheit:
X°C =
(X x 9)
+ 32
5
or X multiplied by nine, then divided by five, then add 32 to the result.
Some interesting temperatures
°C Fact
+5700 Temperature at the Sun's surface
+1760 Temperature of a Bunsen burner flame
+1500 Iron melts
+1065 Gold melts
+962 Silver melts
+100 Water boils
+57 Highest recorded temperature on Earth
+37 Human body temperature
+18 to +20 Room temperature
0 Water freezes
-37 Car antifreeze freezes
-70 Lowest recorded temperature on Earth
-273 Absolute zero (see below!)
Absolute Zero
...
In the 19th century, physicists started to investigate very low temperatures. In fact, they wanted to find out what was the lowest temperature possible. For this they started using a new scale of degrees called Kelvin, after Lord Kelvin, a famous British scientist at that time. This scale uses the same units as the Celcius scale, but it starts at ABSOLUTE ZERO, the temperature at which everything freezes solid, even air. Absolute zero = O K (there is no ° symbol in the Kelvin scale) = - 273°C.
Types of Thermometer
...
The Alcohol Thermometer
...
This was the first to be invented and it is still in use today. The column of alcohol is quite wide, coloured (usually red) to make it easy to read. It is often used for measuring air temperatures which range between - 20°C and +50°C. This is fine because alcohol freezes at - 80°C and boils at +78°C.
The Mercury Thermometer
...
This is the most commonly used laboratory thermometer because temperatures above +78°C often need to be measured. Mercury freezes at - 39°C, so for very low temperatures it is not so useful. Mercury boils at + 357°C which is the upper limit of the thermometer.
The Clinical Thermometer
...
When taking the temperature of a liquid or of air, normally the thermometer should be kept in the substance whilst you take the reading. For a human or animal body this is not possible. A special mercury thermometer was developed so it could be taken out of the body to read the temperature.
The clinical thermometer is a special thermometer which has a sharp bend in its tube that is narrower than the rest of the tube.
To use a clinical thermometer, it is put into the body, either in the mouth (under the tongue) or in the anus. The thermometer is left there for one minute. The mercury rises past the bend to indicate the body temperature. When the thermometer is removed from the body, the mercury shrinks as it cools and draws back into the bulb. However, the column of mercury breaks at the kink and allows you to read the temperature. To get the mercury column back past the bend, a quick shake of the thermometer is all that is needed.
Metric to U.S.
Liquid
1 mL = 0.033814 fl. oz.
1 mL = 0.061024 cu. in.
1 mL = 0.2029 tsp.
1 mL = 0.0676 Tbls.
1 dl = 3.3814 fl. oz.
1 dl = 6.1024 cu. in.
1 dl = 20.29 tsp.
1 dl = 6.76 Tbls.
1 dl = 27.05 fl. dr.
1 dl = 0.423 cups
1 dl = 0.845 gi.
1 dl = 0.21134 pt.
1 dl = 0.10567 qt.
1 l = 33.814 fl. oz.
1 l = 61.024 cu. in.
1 l = 67.6 Tbls.
1 l = 270.5 fl. dr.
1 l = 4.23 cups
1 l = 8.45 gi.
1 l = 2.1134 pt.
1 l = 1.0567 qt.
1 l = 0.26417 gal.
1 l = 0.029353 firkins
Dry
1 l = 1.8162 pt.
1 l = 0.9081 qt.
Weight
1 g = 0.035274 oz.
1 g = 0.0022046 lb.
1 kg = 35.274 oz.
1 kg = 2.2046 lb.
Length
1 mm = 0.03937 in.
1 cm = 0.3937 in.
1 m = 39.37 in.
1 m = 3.281 ft.
1 m = 1.0936 yd.
U.S. to Metric
Liquid
1 tsp. = 4.929 mL
1 Tbls. = 14.787 mL
1 fl. dr. = 3.6967 mL
1 fl. oz. = 29.57353 mL
1 cup = 236.59 mL
1 cup = 2.366 dl
1 cup = 0.2366 l
1 gi. = 118.294 mL
1 gi. = 1.18294 dl
1 gi. = 0.118294 l
1 pt. = 473.1765 mL
1 pt. = 4.731765 dl
1 pt. = 0.4731765 l
1 qt. = 9.4635 dl
1 qt. = 0.94635 l
1 gal. = 37.854 dl
1 gal. = 3.7854 l
1 firkin = 34.069 l
1 hhd = 238.48 l
Dry
1 pt. = 0.551 l
1 qt. = 1.101 l
1 pk. = 8.81 l
1 bu. = 35.25 l
Weight
1 oz. = 28.35 g
1 lb. = 453.59 g
1 lb. = 0.454 kg
Length
1 in. = 25.4 mm
1 in. = 2.54 cm
1 ft. = 304.8 mm
1 ft. = 30.48 cm
1 yd. = 914.4 mm
1 yd. = 91.44 cm
-----------------------------
Abbreviations
Metric
cm = centimeter
dl = deciliter
g = gram
kg = kilogram
l = liter
m = meter
mL = milliliter
mm = millimeter
U.S.
bu. = bushel lb. = pound
fl. dr. = fluid dram oz. = ounce
fl. oz. = fluid ounce pk. = peck
ft. = foot pt. = pint
gal. = gallon qt. = quart
gi. = gill Tbls. = tablespoon
hhd = hogshead tsp. = teaspoon
in. = inch yd. = yard
1 Drop = 1/72 tsp. = 0.002 oz. = 0.065 mL
1 Dash = 1/16 tsp. = 0.010 oz. = 0.308 mL
1 Pinch = 1/8 tsp. = 0.021 oz. = 0.616 mL
-------------------------------
1 tsp. = 1/3 Tbls. = 1/64 cup = 1/6 oz. = 4.93 mL
2 tsp. = 2/3 Tbls. = 1/32 cup = 1/3 oz. = 9.86 mL
3 tsp. = 1 Tbls. = 1/16 cup = 1/2 oz. = 14.79 mL
6 tsp. = 2 Tbls. = 1/8 cup = 1 oz. = 29.57 mL
12 tsp. = 4 Tbls. = 1/4 cup = 2 oz. = 59.15 mL
16 tsp. = 5 1/3 Tbls. = 1/3 cup = 2 2/3 oz. = 78.86 mL
24 tsp. = 8 Tbls. = 1/2 cup = 4 oz. = 118.29 mL
32 tsp. = 10 2/3 Tbls. = 2/3 cup = 5 1/3 oz. = 157.73 mL
36 tsp. = 12 Tbls. = 3/4 cup = 6 oz. = 177.44 mL
48 tsp. = 16 Tbls. = 1 cup = 8 oz. = 236.59 mL
-------------------------------
1 cup = 1/2 pt. = 1/4 qt. = 1/16 gal. = 8 oz. = 236.59 mL
2 cups = 1 pt. = 1/2 qt. = 1/8 gal. = 16 oz. = 473.18 mL
3 cups = 1 1/2 pt. = 3/4 qt. = 3/16 gal. = 24 oz. = 709.76 mL
4 cups = 2 pt. = 1 qt. = 1/4 gal. = 32 oz. = 946.35 mL
5 cups = 2 1/2 pt. = 1 1/4 qt. = 5/16 gal. = 40 oz. = 1.18 l
6 cups = 3 pt. = 1 1/2 qt. = 3/8 gal. = 48 oz. = 1.42 l
8 cups = 4 pt. = 2 qt. = 1/2 gal. = 64 oz. = 1.89 l
10 cups = 5 pt. = 2 1/2 qt. = 5/8 gal. = 80 oz. = 2.37 l
12 cups = 6 pt. = 3 qt. = 3/4 gal. = 96 oz. = 2.84 l
16 cups = 8 pt. = 4 qt. = 1 gal. = 128 oz. = 3.79 l
-------------------------------
1 gill = 1/2 cup
1 peck = 2.33 gal.
1 bushel = 9.31 gal.
Abbreviations
gal. = gallon
l = liter
mL = milliliter
oz. = ounce
pt. = pint
qt. = quart
Tbls. = tablespoon
tsp. = teaspoon
Names for Large Numbers
The English names for large numbers are coined from the Latin names for small numbers n by adding the ending -illion suggested by the name "million." Thus billion and trillion are coined from the Latin prefixes bi- (n = 2) and tri- (n = 3), respectively. In the American system for naming large numbers, the name coined from the Latin number n applies to the number 103n+3. In a system traditional in many European countries, the same name applies to the number 106n.
In particular, a billion is 109 = 1 000 000 000 in the American system and 1012 = 1 000 000 000 000 in the European system. For 109, Europeans say "thousand million" or "milliard."
Although we describe the two systems today as American or European, both systems are actually of French origin. The French physician and mathematician Nicolas Chuquet (1445-1488) apparently coined the words byllion and tryllion and used them to represent 1012 and 1018, respectively, thus establishing what we now think of as the "European" system. However, it was also French mathematicians of the 1600's who used billion and trillion for 109 and 1012, respectively. This usage became common in France and in America, while the original Chuquet nomenclature remained in use in Britain and Germany. The French decided in 1948 to revert to the Chuquet ("European") system, leaving the U.S. as the chief standard bearer for what then became clearly an American system.
In recent years, American usage has eroded the European system, particularly in Britain and to a lesser extent in other countries. This is primarily due to American finance, because Americans insist that $1 000 000 000 be called a billion dollars. In 1974, the government of Prime Minister Harold Wilson announced that henceforth "billion" would mean 109 and not 1012 in official British reports and statistics. The Times of London style guide now defines "billion" as "one thousand million, not a million million."
The result of all this is widespread confusion. Anyone who uses the words "billion" and "trillion" internationally should make clear which meaning of those words is intended. On the Internet, some sites outside the U.S. use the compound designation "milliard/billion" to designate the number 1 000 000 000. In science, the names of large numbers are usually avoided completely by using the appropriate SI prefixes. Thus 109 watts is a gigawatt and 1012 joules is a terajoule. Such terms cannot be mistaken.
There is no real hope of resolving the controversy in favor of either system. Americans are not likely to adopt the European nomenclature, and Europeans will always regard the American system as an imposition. However, it is possible to imagine a solution: junk both Latin-based systems and move to a Greek-based system in which, for n > 3, the Greek number n is used to generate a name for 103n. (The traditional names thousand and million are retained for n = 1 and 2 and the special name gillion, suggested by the SI prefix giga-, is proposed for n = 3.)
n =
103n =
American
name
European
name
SI prefix
Greek-based
name
(proposed)
3
109
billion milliard
giga-
gillion
4
1012
trillion billion
tera-
tetrillion
5
1015
quadrillion billiard
peta-
pentillion
6
1018
quintillion trillion
exa-
hexillion
7
1021
sextillion trilliard
zetta-
heptillion
8
1024
septillion quadrillion
yotta-
oktillion
9
1027
octillion quadrilliard
ennillion
10
1030
nonillion quintillion
dekillion
11
1033
decillion quintilliard
hendekillion
12
1036
undecillion sextillion
dodekillion
13
1039
duodecillion sextilliard
trisdekillion
14
1042
tredecillion septillion
tetradekillion
15
1045
quattuordecillion septilliard
pentadekillion
16
1048
quindecillion octillion
hexadekillion
17
1051
sexdecillion octilliard
heptadekillion
18
1054
septendecillion nonillion
oktadekillion
19
1057
octodecillion nonilliard
enneadekillion
20
1060
novemdecillion decillion
icosillion
21
1063
vigintillion decilliard
icosihenillion
22
1066
unvigintillion undecillion
icosidillion
23
1069
duovigintillion undecilliard
icositrillion
24
1072
trevigintillion duodecillion
icositetrillion
25
1075
quattuorvigintillion duodecilliard
icosipentillion
26
1078
quinvigintillion tredecillion
icosihexillion
27
1081
sexvigintillion tredecilliard
icosiheptillion
28
1084
septenvigintillion quattuordecillion
icosioktillion
29
1087
octovigintillion quattuordecilliard
icosiennillion
30
1090
novemvigintillion
quindecillion
triacontillion
31
1093
trigintillion
quindecilliard
triacontahenillion
32
1096
untrigintillion sexdecillion
triacontadillion
33
1099
duotrigintillion sexdecilliard
triacontatrillion
This process can be continued indefinitely, but one has to stop somewhere. The name centillion (n = 100) has appeared in many dictionaries. A centillion is 10303 (1 followed by 303 zeroes) in the American system and a whopping 10600 (1 followed by 600 zeroes) in the European system.
Finally, there is the googol, the number 10100 (1 followed by 100 zeroes). Invented more for fun than for use, the googol lies outside the regular naming systems. The googol equals 10 duotrigintillion in the American system, 10 sexdecilliard in the European system, and 10 triacontatrillion in the proposed Greek-based system.
The googolplex (1 followed by a googol of zeroes) is far larger than any of the numbers discussed here.
The Metric System
Designed during the French Revolution of the 1790's, the metric system brought order out of the conflicting and confusing traditional systems of weights and measures then being used in Europe. Prior to the introduction of the metric system, it was common for units of length, land area, and weight to vary, not just from one country to another but from one region to another within the same country. As the modern nations were gradually assembled from smaller kingdoms and principalities, confusion simply multiplied. Merchants, scientists, and educated people throughout Europe realized that a uniform system was needed, but it was only in the climate of a complete political upheaval that such a radical change could actually be considered.
The metric system replaces all the traditional units, except the units of time and of angle measure, with units satisfying three conditions:
(1) One fundamental unit is defined for each quantity. These units are now defined precisely in the International System of Units.
(2) Multiples and fractions of these fundamental units are created by adding prefixes to the names of the defined units. These prefixes denote powers of ten, so that metric units are always divided into tens, hundreds, thousands, etc. The original prefixes included milli- for 1/1,000, centi- for 1/100, deci- for 1/10, deka- for 10, hecto- for 100, and kilo- for 1,000.
(3) The fundamental units are defined rationally and are related to each other in a rational fashion.
The metric units were defined in an elegant way unlike any traditional units of measure. The Earth itself was selected as the measuring stick. The meter was defined to be one ten-millionth of the distance from the Equator to the North Pole. The liter was to be the volume of one cubic decimeter, and the kilogram was to be the weight of a liter of pure water. It didn't turn out quite like this, because the scientific methods of the time were not quite up to the task of measuring these quantities precisely, but the actual metric units come very close to the design.
The metric system was first proposed in 1791. It was adopted by the French revolutionary assembly in 1795, and the first metric standards (a standard meter bar and kilogram bar) were adopted in 1799. There was considerable resistence to the system at first, and its use was not made compulsory in France until 1837. The first countries to actually require use of the metric system were Belgium, the Netherlands, and Luxembourg, in 1820.
Around 1850 a strong movement began among scientists, engineers, and businessmen in favor of a international system of weights and measures. The scientific and technical revolution was well underway and a global economy was developing. The need for uniformity in measurement was becoming obvious. Furthermore, the metric system was the only real choice available. The only possible competitor, the British Imperial system, was so closely tied to the British Empire it was not even acceptable to the Americans, let alone to non-English speakers.
Between 1850 and 1900 the metric system made rapid progress. It was adopted throughout continental Europe, in Latin America, and in many countries elsewhere. It became firmly established as a key part of the language of science.
In the 1870s the French made a crucial decision to turn control of the system over to an international body. In 1875, most of the leading industrialized countries (including the United States, but not Britain) signed the Treaty of the Meter. The treaty established the International Bureau of Weights and Measures, which has presided ever since over what we now call the International System of Units. It also provided for distribution of copies of the metric standards throughout the world and for continuing consultation and periodic revision and improvement of the system through regular meetings of a General Conference of Weights and Measures. The 22nd General Conference met in October 2003.
Since 1875 the eventual triumph of the metric system in science and international commerce has been assured, despite continuing popular opposition in Britain and the United States. In fact, the metric system has met popular opposition in every country at the time of its adoption. People don't want to change their customary units, which are part of how they see and control the world. It is naturally disturbing to do so. This opposition has been largely overcome everywhere, except in the U.S., by economic necessity: the need to participate fully in the global economic system. Even in the U.S., economic needs assure the continued creeping adoption of the system in one area and then another.
Those Americans opposing adoption of metric units often argue that the metric system is abstract and intellectual or that its use would embroil us in calculations. This is not true. The metric system has been the customary measurement system in France for almost two centuries, in the rest of continental Europe for at least one century, and in the rest of the world for a least a generation or two. Most people in the world know exactly how long a kilometer is, how large a liter is, how much a kilogram weighs, and how warm 25 °C is, because they use these units every day of their lives in the same way Americans use miles, gallons, and pounds.
Outside Britain and the United States there is almost no need to convert metric units into something else. In fact, the way to avoid conversion formulas is to adopt the metric system. As long as Britons and Americans continue to use traditional units, they will have to remember how these units relate to the metric units.
A note:
Widespread use of the metric system has not meant the complete elimination of traditional units, nor has it stopped the continuing creation of new units, many metric but some not, to meet new needs. The purpose of this dictionary is to provide information on all commonly used units, old and new. My only interest here is in preserving and disseminating information on units, both metric and traditional, for anyone who would like to know more about them.
The International System of Units (SI)
All systems of weights and measures, metric and non-metric, are linked through a network of international agreements supporting the International System of Units. The International System is called the SI, using the first two initials of its French name Système International d'Unités. The key agreement is the Treaty of the Meter (Convention du Mètre), signed in Paris on May 20, 1875. 48 nations have now signed this treaty, including all the major industrialized countries. The United States is a charter member of this metric club, having signed the original document back in 1875.
The SI is maintained by a small agency in Paris, the International Bureau of Weights and Measures (BIPM, for Bureau International des Poids et Mesures), and it is updated every few years by an international conference, the General Conference on Weights and Measures (CGPM, for Conférence Générale des Poids et Mesures), attended by representatives of all the industrial countries and international scientific and engineering organizations. The 22nd CGPM met in October 2003; the next meeting will be in 2007. As BIPM states on its web site, "The SI is not static but evolves to match the world's increasingly demanding requirements for measurement."
At the heart of the SI is a short list of base units defined in an absolute way without referring to any other units. The base units are consistent with the part of the metric system called the MKS system. In all there are seven SI base units:
the meter for distance,
the kilogram for mass,
the second for time,
the ampere for electric current,
the kelvin for temperature,
the mole for amount of substance, and
the candela for intensity of light.
Other SI units, called SI derived units, are defined algebraically in terms of these fundamental units. For example, the SI unit of force, the newton, is defined to be the force that accelerates a mass of one kilogram at the rate of one meter per second per second. This means the newton is equal to one kilogram meter per second squared, so the algebraic relationship is N = kg·m·s-2. Currently there are 22 SI derived units. They include:
the radian and steradian for plane and solid angles, respectively;
the newton for force and the pascal for pressure;
the joule for energy and the watt for power;
the degree Celsius for everyday measurement of temperature;
units for measurement of electricity: the coulomb (charge), volt (potential), farad (capacitance), ohm (resistance), and siemens (conductance);
units for measurement of magnetism: the weber (flux), tesla (flux density), and henry (inductance);
the lumen for flux of light and the lux for illuminance;
the hertz for frequency of regular events and the becquerel for rates of radioactivity and other random events;
the gray and sievert for radiation dose; and
the katal, a unit of catalytic activity used in biochemistry.
Future meetings of the CGPM may make additions to this list; the katal was added by the 21st CGPM in 1999.
In addition to the 29 base and derived units, the SI permits the use of certain additional units, including:
the traditional mathematical units for measuring angles (degree, arcminute, and arcsecond);
the traditional units of civil time (minute, hour, day, and year);
two metric units commonly used in ordinary life: the liter for volume and the tonne (metric ton) for large masses;
the logarithmic units bel and neper (and their multiples, such as the decibel); and
three non-metric scientific units whose values represent important physical constants: the astronomical unit, the atomic mass unit or dalton, and the electronvolt.
The SI currently accepts the use of certain other metric and non-metric
