A **metrified Imperial system** is a proposal for a metrication and unification of the English systems of measures. Usually the inch is set to 25 mm, the pint to 500 ml and the pound to 500 g and the rest accordingly.

## TransitionEdit

Nowadays all Imperial units are defined in terms of their metric/SI equivalents, but mostly with quite odd factors. This choice was made to ensure largest possible continuity, but over time there have been several proposals to round off the values, which is thought to ease transition towards the metric system.

## Royal System Edit

One of the earliest still known and most extensive proposals of a metrified Imperial system is from the early 1820s and is attributed to William Huskisson, but it wasn't embodied into the 1824 reformation of the Imperial system at all.

### Length Edit

calibre | ≡ 1/100 inch | = 250 µm = ¼ mm | |
---|---|---|---|

point | ≡ 1/6 line | = 1/75 inch | = 333 1/3 µm = 1/3 mm |

line | ≡ 10/125 inch | ≈ 1/12 inch | = 2 mm |

barleycorn | ≡ 1/3 inch | = 8 1/3 mm | |

digit | ≡ 1/16 foot | = ¾ inch | = 18¾ mm = 1.875 cm |

finger | ≡ 7/8 inch | = 21.875 mm = 2.1875 cm | |

inch | ≡ 25 mm = 2½ cm | ||

stick | ≡ 2 inch | = 50 mm = 5 cm | |

nail | = 3 digit ≡ ¼ span | = 2¼ inch | = 56¼ mm = 5.625 cm |

palm | ≡ 4 digit | = 3 inch | = 75 mm = 7.5 cm |

hand | ≡ 1 palm + 1 inch | = 4 inch | = 100 mm = 1 dm |

shaftment | ≡ 2 palm | = 6 inch | = 150 mm = 1.5 dm |

link | ≡ 8 inch | = 200 mm = 2 dm | |

span | ≡ 3 palm | = 9 inch | = 225 mm = 2.25 dm |

foot | = 4 palm | ≡ 12 inch | = 300 mm = 3 dm |

cubit | ≡ 1½ foot | = 18 inch | = 450 mm = 4.5 dm |

pace | ≡ 32 inch | = 800 mm = 8 dm | |

yard | ≡ 3 foot | = 36 inch | = 900 mm = 9 dm |

ell | ≡ 20 nail | = 45 inch | = 1.125 m |

grade | ≡ 2 pace | = 64 inch | = 1.6 m |

fathom | ≡ 6 foot | = 72 inch | = 1.8 m |

rod (pole, perch) | ≡ 25 link | = 200 inch | = 5 m |

rope | ≡ 20 foot | = 240 inch | = 6 m |

chain | ≡ 4 rod | = 800 inch | = 20 m = 2 dam |

cable length | ≡ 100 fathom | = 7 200 inch | = 180 m = 1.8 hm |

furlong | ≡ 10 chain | = 8 000 inch | = 200 m = 2 hm |

mile | ≡ 8 furlong = 2 000 pace | = 64 000 inch | = 1.6 km |

nautical mile | ≡ 10 cable = 2 000 yard | = 72 000 inch | = 1.8 km |

league | ≡ 3 mile | = 192 000 inch | = 4.8 km |

sea league | ≡ 3 nautical mile | = 216 000 inch | = 5.4 km |

There is also a version with a *nautical mile* of 1.85 km, which is much closer to 1' of the circumference of Earth and its current value of 1.852 km. The mile is about ¼ mrad Earth, while a kilometre was at that time believed to be 0.01 grad Earth.
The pace was originally 2½ foot, i.e. 30 inches or 7.5 dm, but with 32 inches or 8 dm a mile retains both its definitions: the old Roman one of being 1000 *gradus* and the English one of 8 *furrows long*. Also note, that a 1.8-km seamile is 2 000 yards or nine furlongs.

### Area Edit

For area measurement of course all length units can simply be squared, e.g. 1 foot² = 9 dm². Those are not explicitly listed here.

board | ≡ 1 inch × 1 foot | = 12 inch² | = 7 500 mm² = 75 cm² |
---|---|---|---|

rood | ≡ 1 furlong × 1 rod = 40 rod² | = 1 600 000 inch² | = 1 000 m² = 10 a |

acre | ≡ 1 furlong × 1 chain = 160 rod² | = 6 400 000 inch² | = 4 000 m² = 40 a |

yardland, virgate | ≡ ¼ hide = 25 acre | = 160 000 000 inch² | = 125 000 m² = 12.5 ha |

hide | ≡ 100 acre | = 640 000 000 inch² | = 400 000 m² = 40 ha |

barony | ≡ 40 hide | = 25 600 000 000 inch² | = 16 km² |

### Volume, capacity Edit

For volume measures of course all length units can simply be cubed, e.g. 1 foot³ = 27 dm³ = 27 l. Those are not explicitly listed here.

perch | ≡ 1 perch × 1½ foot × 1 foot | = 42 768 inch³ | = 675 l = 6.75 hl |
---|---|---|---|

freight ton | ≈ 40 foot³ | = 64 000 inch³ | ≡ 1 m³ = 1 kl |

load | ≡ 50 foot³ | = 86 400 inch³ | = 1.35 m³ |

register ton | ≡ 100 foot³ | = 172 800 inch³ | = 2.7 m³ |

acre-foot | ≡ 1 acre × 1 foot | = 19 200 000 inch³ | = 12 000 m³ = 12 dam³ |

There are at least two gallon-based variants, one with a 4-litre gallon, the other with a 5-litre one. With 5 litre a gallon of water still weighs 10 pounds; note the correspondence between the volume and mass units which share a name.

minim | ≡ 1/20 scruple | = 1/240 inch³ | = 65.104 1¯6 µl |
---|---|---|---|

scruple | ≡ 1/3 drachm | = 1/12 inch³ | = 1.302 08¯3 ml |

dra(ch)m | ≡ 1/8 ounce | = ¼ inch³ | = 3.906 250 ml |

teaspoon | ≡ 1/3 tablespoon | = 1/3 inch³ | = 5.208¯3 ml |

tablespoon | ≡ 1/16 cup | = 1 inch³ | = 15.625 ml = 1.562 500 cl |

ounce | ≡ ¼ gill | = 2 inch³ | = 31¼ ml = 3.125 cl |

gill | ≡ ¼ pint | = 8 inch³ | = 125 ml = 1¼ dl |

cup | ≡ ½ pint = 8 ounce | = 16 inch³ | = 250 ml = 2½ dl |

pint | ≡ ½ quart | = 32 inch³ | = 500 ml = 5 dl |

≡ 4/5 quart | |||

quart | ≡ ¼ gallon | = 64 inch³ | = 1 l |

= 80 inch³ | = 1.25 l | ||

gallon | = 256 inch³ | ≡ 4 l | |

= 320 inch³ | ≡ 5 l | ||

peck | ≡ 2 gallon | = 512 inch³ | = 8 l |

= 640 inch³ | = 10 l | ||

kenning | ≡ 2 peck | = 1 024 inch³ | = 16 l = 1.6 dal |

= 1 280 inch³ | = 20 l = 2 dal | ||

bushel | ≡ 2 kenning | = 2 048 inch³ | = 32 l = 3.2 dal |

= 2 560 inch³ | = 40 l = 4 dal | ||

firkin | ≡ ½ kilderkin | = 2 560 inch³ | = 40 l = 4 dal |

= 3 200 inch³ | = 50 l = 4 dal | ||

rundlet | ≡ 1/7 pipe | = 4 389 3/7 inch³ | ≈ 68.57 l = 6.857 dal |

= ½ tierce | = 4 800 inch³ | ≡ 75 l = 7½ dal | |

kilderkin | ≡ ½ tierce | = 5 120 inch³ | = 80 l = 8 dal |

= 6 400 inch³ | = 100 l = 1 hl | ||

barrel | ≡ ½ hogshead | = 7 680 inch³ | = 120 l = 1.2 hl |

= 8 000 inch³ | = 125 l = 1¼ hl | ||

tierce | ≡ 1/3 pipe = ½ pon | = 10 240 inch³ | = 160 l = 1.6 hl |

≡ 3 firkin | = 9 600 inch³ | = 150 l = 1½ hl | |

hogshead | ≡ ½ pipe | = 15 360 inch³ | = 240 l = 2.4 hl |

= 16 000 inch³ | = 250 l = 2½ hl | ||

quarter | ≡ 8 bushel | = 16 384 inch³ | = 256 l = 2.56 hl |

= 20 480 inch³ | = 320 l = 3.2 hl | ||

≡ ¼ tun = 1 hogshead | = 16 000 inch³ | = 250 l = 2½ hl | |

puncheon, tertian | ≡ 1/3 tun | = 20 480 inch³ | = 320 l = 3.2 hl |

≡ 3 kilderkin | = 19 200 inch³ | = 300 l = 3 hl | |

pipe | ≡ ½ tun | = 30 720 inch³ | = 480 l = 4.8 hl |

= 32 000 inch³ | = 500 l | ||

tun | = 240 gallon | = 61 440 inch³ | ≡ 960 l = 9.6 hl |

= 192 gallon | |||

= 250 gallon | = 64 000 inch³ | ≡ 1000 l = 1 m³ | |

= 200 gallon |

### Mass, weight Edit

The Troy pound gets replaced by the *libra*, the abbreviation for the real pound has to change accordingly.

grain | ≡ 1/20 scruple | = 1/7 680 pound | = 65.104 1¯6 mg = 6.510 41¯6 cg |
---|---|---|---|

carat | = 1/2 500 pound | ≡ 200 mg = 2 dg | |

scruple | ≡ 1/3 dram | = 1/384 pound | = 1.302 08¯3 g |

pennyweight | ≡ 1/20 ounce = 1/240 libra | = 1/320 pound | = 1.562 500 g |

dram | ≡ 1/8 ounce | = 1/128 pound | = 3.906 250 g |

ounce | = 1/12 libra | ≡ 1/16 pound | = 31.25 g = 3.125 dag |

libra | = 5760 grain | ≡ ¾ pound | = 375 g = 3¾ hg |

pound | = 7680 grain | ≡ 500 g = 5 hg | |

clove, nail | ≡ ½ stone | = 6¼ pound | = 3.125 kg |

stone | ≡ ½ tod | = 12½ pound | = 6.25 kg |

tod, quarter | ≡ ¼ hundredweight | = 25 pound | = 12.5 kg |

hundredweight | ≡ 100 pound | = 50 kg | |

wey | ≡ 1½ hundredweight | = 150 pound | = 75 kg |

sack | ≡ 2 wey | = 300 pound | = 150 kg |

ton, tonne | ≡ 20 hundredweight | = 2 000 pound | = 1 Mg = 1 t |

last | ≡ 12 sack | = 3 600 pound | = 1.8 Mg = 1.8 t |

### Derived units Edit

The *knot* is acknowledged as 1 nautical mile per hour.

Weight and mass are often confused and it is not surprising, that in many proposals there is no explict mention of (gravitational) force, but the pound-force is still 1 pound times Gee, see also kilopond. The poundal (1 lb.•ft./s²) equals 0.15 N with the above redefinitions of pound and foot.

Likewise you get the units of *pressure*, e.g. pound-force/inch² or *inch mercury*. For *energy* or heat, a British thermal unit is almost exactly 1 kJ already. The units of power are rather new, but it makes sense to round a horse power to 750 W.

### Kitchen Edit

There are other metrified values for *cup* (240 mL or 250 mL), *tablespoon* (15 mL or 20 mL) and *teaspoon* (5 mL) in use today, independently from all the other units.

## American independence Edit

[1]
At the First Congress, which met in 1789 when the metric system had not yet been developed in France, the system of units to be used in the future USA was one point of discussion. The Congress would have had (and still has) the constitutional right (article I, section 8) to decide on a standard of weights and measurement, but *never* did so.

In the meeting Thomas Jefferson was employed to find the best system of weights and measures to be used in the USA. The decimal dollar had already been introduced at that time. In mid-1790 he proposed two systems of units, one evolutionary with a mere refinement of definitions and simplification of the existing English system, the other one revolutionary being decimal and only reusing some of the traditional names.

In coordination with scientists in France, he selected the second pendulum at 45° latitude as the basic reference. The pendulum was estimated to be 39.14912 English inches of that time long (an inch was much later defined to be 25.4 mm) or 1.5 times that for a vibrating rod (58.72368 inches), that is about 994,4 mm.

In the evolutionary approach, the foot was to be derived from that length by a simple integer factor, which would be either three or five, i.e. lengthening it from the traditional value by 1.04970¯6 inches to ca. 331.463 mm or shortening it by 0.255264 inches to ca. 298.317 mm. For practical purposes he wanted the rod to be 58¾ (new) inches long, an increase of less than 0.045%.

The revolutionary system was quite similar to the metric system, except the mentioned difference of about 5½ mm between the second rod at 45° and the 10,000th part of the distance from the northpole to the equator. Also it didn't have the concept of prefixes at all. A very similar system was a base of discussion in France after the revolution of 14 July 1789, with Jefferson observing.

Length | |
---|---|

foot | = 12 inches |

yard | = 3 feet |

ell | = 3¾ feet |

fathom | = 6 feet |

perch, pole | = 5½ yards |

furlong | = 40 poles |

mile | = 8 furlongs |

league | = 3 miles |

Area | |

rood | = 40 square poles |

acre | = 4 roods |

Volume | |

gill | = ¼ pint |

pint | = ½ quart |

quart | = ½ pottle |

pottle | = ½ gallon |

gallon | = 270 cubic inches |

peck | = 2 gallons |

bushel, firkin | = 4 pecks |

strike, kilderkin | = 2 bushel or firkin |

coomb, barrel | = 2 strikes or kilderkins |

quarter, hogshead | = 2 coombs or barrels |

tierce | = 4/3 hogshead |

pipe, butt, puncheon | = 2 hogsheads |

ton | = 2 pipes |

Weight | |

grain | = 1/24 pennyweight |

pennyweight | = 1/18 ounce |

ounce | = 1/1000 weight of 1 cubic foot of rain water at standard temperature |

pound | = 16 ounces |

Length | ||
---|---|---|

point | = 1/10 line | |

line | = 1/10 inch | |

inch | = 1/10 foot | |

foot | (base) | = ca. 994,4 ÷ 5 mm |

decad(e) | = 10 foot | |

rood | = 10 decade | |

furlong | = 10 rood | |

mile | = 10 furlong | ca. 2 traditional miles |

Area | ||

rood | = 1 rood × 1 rood | |

Volume | ||

metre | = 1/10 demi-pint = 1 inch³ | |

demi-pint | = 1/10 pottle = 2 × 2 × 2½ inch³ | |

pottle | = 1/10 bushel = 5 × 5 × 4 inch³ | |

bushel | = 1 foot³ | ca ¾ traditional bushel |

quarter | = 10 bushels | |

last, double ton | = 10 quarters | |

Weight | ||

mite | = 1/10 minim | |

minim, demi-grain | = 1/10 carat | |

carat | = 1/10 double-scruple | |

double-scruple | = 1/10 ounce | |

ounce | = 1/1000 the weight of 1 bushel of water | |

pound | = 10 ounces | |

stone | = 10 pounds | |

kental | = 16 stones | |

hogshead | = 10 kentals |

## Isolated Edit

Besides redefinitions of the whole system, which try to keep the values close and the system immanent factors intact, there were and are simple approximations of Imperial units in metric.

### Length Edit

- point (352 7/9 µm)
- 250 µm = ¼ mm, 350 µm, 375 µm = 3/8 mm
- inch (25.4 mm)
- 2.5 cm = ¼ dm, 3 cm
- foot (12 inch = 0.3048 m)
- 2.5 dm = ¼ m, 3 dm, 3.¯3 dm = 1/3 m
- yard (3 foot = 0.9144 m)
- 0.9 m, 1 m
- fathom (6 foot = 1.8288 m)
- 1.8 m, 1.85 m, 1.852 m, 2 m
- rod, pole, perch (192 inch = 5.0292 m)
- 5 m
- chain (4 rod = 20.1168 m)
- 20 m
- cable (1/10 sea mile)
- 180 m, 185 m, 185.2 m, 200 m
- furlong (10 chain = 201.168 m)
- 200 m
- mile (8 furlong = 1.609344 km)
- 1.5 km, 1.6 km, 1.609 km, 1.61 km, 2 km
- nautical mile (6080 foot = 1.853184 km)
- 1.8 km, 1.85 km, 1.852 km, 1.853 km, 1.9 km, 2 km; 1 equatorial minute, 1 meridian minute

### Area Edit

- acre (4046.8564224 m²)
- 40 a, 40.5 a, 50 a = ½ ha

### Volume, capacity Edit

- scruple (1/3 drachm ≅ 1.184 ml)
- 1 ml, 1.2 ml, 1.25 ml = 1¼ ml
- drachm/dram (1/8 ounce ≅ 3.552 ml | 3.697 ml)
- 3.5 ml = 3½ ml, 3.7 ml, 3.75 ml = 3¾ ml
- ounce (1/5 gill ≅ 28.413 ml | ¼ gill ≅ 29.574 ml)
- 25 ml, 27.5 ml, 28 ml, 28.5 ml, 30 ml
- gill (¼ pint ≅ 142.065 | 118.294 ml)
- 100 ml, 120 ml, 140 ml, 150 ml
- pint (¼ gallon ≅ 568.26 ml | 473.176 ml | 550.61 ml)
- 475 ml = 4¾ dl, 500 ml = ½ l, 550 ml = 5½ dl, 600 ml
- quart (½ gallon ≅ 1.137 l | 0.946 l | 1.101 l)
- 1 l, 1.1 l
- gallon (≅ 4.546 l | 3.785 l | 4.405 l)
- 3.8 l, 4 l, 4.4 l, 4.5 l, 5 l
- (petrol) barrel (35 gallon ≅ 159,113 l | 42 gallon ≅ 158,987 l)
- 159 l, 160 l
- peck (2 gallon ≅ 9.092 l | 8.810 l)
- 8.8 l, 9 l, 10 l
- bushel (4 peck ≅ 36.368 l | 35.239 l)
- 35 l, 36 l, 40 l
- quarter/hogshead (8 bushel ≅ 290.9 l | 281.9 l)
- 250 l ≅ volume of ¼ t water, 256 l, 280 l, 290 l, 300 l

- teaspoon
- 5 ml
- tablespoon
- 15 ml
- cup
- 225 ml, 240 ml, 250 ml = ¼ l

### Mass, weight Edit

- grain (64.79891 mg)
- 50 mg
- pennyweight (24 grain ≅ 1,555 g)
- 1.5 g, 2 g = 10 carat
- dram (1⁄16 ounce ≅ 1,772 g)
- 1.5 g, 1.75 g, 2 g
- ounce (1⁄16 pound ≅ 28,35 g | 20 pennyweight ≅ 31.103 g)
- 25 g, 28.5 g, 30 g | 30 g, 33 1/3 g
- pound (7000 grain ≅ 453,592 g | 5760 grain ≅ 373.242 g)
- 450 g, 500 g | 350 g, 375 g, 400 g
- stone (14 pound ≅ 6.35 kg)
- 5 kg, 6.25 kg
- quarter (¼ hundredweight ≅ 11.34 kg | 12.701 kg)
- 12.5 kg
- hundredweight (100 pound ≅ 45.359 kg | 50.802 kg)
- 45 kg, 50 kg
- ton (20 hundredweight ≅ 0.907 t | 1.016 t)
- 0.9 t, 1 t

## See also Edit

## External linksEdit

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