Metrified Imperial system Guide, Meaning , Facts, Information and Description
The 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.Nowadays all Imperial units are defined in terms of their metric 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.
System
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
| 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 | = ca. 1/12 inch | = 2 mm |
| barleycorn | = 1/3 inch | = 8 1/3 mm | |
| digit | = 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 | = 3 inch | = 75 mm = 7.5 cm | |
| hand | = 1 palm + 1 inch | = 4 inch | = 100 mm = 1 dm |
| shaftment | = 6 inch | = 150 mm = 1.5 dm | |
| link | = 1/25 rod | = 8 inch | = 200 mm = 2 dm |
| span | = 3 palm | = 9 inch | = 225 mm = 2.25 dm |
| foot | = 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 | = 7.2e3 inch | = 180 m = 1.8 hm |
| furlong | = 10 chain | = 8e3 inch | = 200 m = 2 hm |
| mile | = 8 furlong = 2 000 pace | = 64e3 inch | = 1.6 km |
| nautical mile | = 10 cable = 2 000 yard | = 72e3 inch | = 1.8 km |
| league | = 3 mile | = 192e3 inch | = 4.8 km |
| sea league | = 3 nautical mile | = 216e3 inch | = 5.4 km |
| board | = 1 inch × 1 foot | = 12 inch² | = 7 500 mm² = 75 cm² |
|---|---|---|---|
| rood | = 1 furlong × 1 rod = 40 rod² | = 1.6e6 inch² | = 1 000 m² = 10 a |
| acre | = 1 furlong × 1 chain = 160 rod² | = 6.4e6 inch² | = 4 000 m² = 40 a |
| yardland, virgate | = ¼ hide = 25 acre | = 160e6 inch² | = 125 000 m² = 12.5 ha |
| hide | = 100 acre | = 640e6 inch² | = 400 000 m² = 40 ha |
| barony | = 40 hide | = 25.6e9 inch² | = 16 km² |
| perch | = 1 perch × 1½ foot × 1 foot | = 42.768e3 inch³ | = 675 l = 6.75 hl |
|---|---|---|---|
| freight ton | = ca. 40 foot³ | = 64e3 inch³ | = 1 m³ = 1 kl |
| load | = 50 foot³ | = 86.4e3 inch³ | = 1.35 m³ |
| register ton | = 100 foot³ | = 172.8e3 inch³ | = 2.7 m³ |
| acre-foot | = 1 acre × 1 foot | = 19.2e6 inch³ | = 12 000 m³ = 12 dam³ |
| 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 | ||
| quarter | = 8 bushel | = 4 096 inch³ | = 256 l = 2.56 hl |
| = 5 120 inch³ | = 320 l = 3.2 hl | ||
| firkin | = ½ kilderkin | = 2 560 inch³ | = 40 l = 4 dal |
| rundlet | = 1/7 pipe | = 4 389 3/7 inch³ | ~= 68.57 l = 6.857 dal |
| kilderkin | = ½ tierce | = 5 120 inch³ | = 80 l = 8 dal |
| barrel | = ½ hogshead | = 7 680 inch³ | = 120 l = 1.2 hl |
| tierce | = 1/3 pipe = ½ puncheon | = 10 240 inch³ | = 160 l = 1.6 hl |
| hogshead | = ½ pipe | = 15 360 inch³ | = 240 l = 2.4 hl |
| puncheon (pon), tertian | = 1/3 tun | = 20 480 inch³ | = 320 l = 3.2 hl |
| pipe | = ½ tun | = 30 720 inch³ | = 480 l = 4.8 hl |
| tun | = 240 gallon | = 61 440 inch³ | = 960 l = 9.6 hl |
| = 192 gallon |
Mass, weight
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 |
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.
; teaspoon : 5 ml
; tablespoon : 15 ml
; cup : 225 ml, 240 ml, 250 ml = ¼ lDerived units
The knot is acknowledged as 1 nautical mile per hour.Kitchen
There are other metrified values for cup (240 ml or 250 ml), tablespoon (15 ml) and teaspoon (5 ml) in use today, independently from all the other units.Isolated
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
; 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 minuteArea
; acre (4046.8564224 m²) : 40 a, 40.5 a, 50 a = ½ haVolume, capacity
; 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