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- U7 *
A set of imperial conversion factors, based on factors that are made of the
primes 2, 3, 5, 7.
foot = 32/105 metre = 64/21 Linn ; 1 metre = 3ft 3 3/8 in
pound = 200 / 441 kg, Pondd ; 1 kg, Pondd = 15435 grains
Using this conversion factors, we see that 1 mm : 1 kg as 1 in : 4 stones.
Also, 25 mm : 1 inch as 1 tonne : 1 ton.
Dividing the kg into 35 oz \ 7 dr \ 3 scr \ 7 carats \ 3 grains, gives an oz
of 441 gt, and the corresponding lb of 7056 gt. The kg is then 2 lb 3 oz exactly.
- UB (1895) *
A set of imperial conversion factors, being the combination
of Broch's pound and a yard, constructed in the style of the metre, and
measured for the BIPM of 1898.
foot = 0.9143992/3 metre Beniot A (1895)
pound = 7/15.43235639 kilogram
Beniot found the yard to be 0.9143992 metres. This unit is also used
in Geodetic surveys, the two principal forms being as follows:
39.370 113 000 000: Beniot B (1895) 1 metre = 39.370 113 inches
39.370 113 184 701: Beniot A (1895) 1 yard = 0.9143992 metres
In 1883, the kilogram was 15432.35639 grains for Broch
- UC (1878) *
The 1878 set of imperial conversion factors, based on
foot = 1/3/1.09362311 metres: Clarke 1866: 1 metre = 1.09362311 yards
pound = 7/15.43235639 kilogram: by Broch, 1 kilogram = 15432.35639 grains
Captian Clarke did a geodetic survey of the world, the results of which
are in use to this day, although satelite surveys are progressively
displacing these. Because the surveys are this precise, a number of
slightly different forms are known:
39.370 431 960 000: 1 metre = 1.09362311 yards: Exact: see Clarke.
39.370 432 000 000: 1 metre = 39.370432 inches
39.370 432 014 867: 1 foot = 0.304 797 265 metres [Australia]
Clarke also found these earlier measurements, much used in
39.369 971 101 347: 1 yard(1865) = 0.9144025 metre
39.370 141 967 763: 1 Indian ft = 0.99999566 ft(1865)
39.370 142 000 000: 1 Indian foot as commonly used.
- UES -- Unified Electric System *
The UES is a system of prefix and suffix rules, designed to quickly
identify the derived systems. In its simplest form, it regards the
gaussian as a mix of electric and magnetic units, and unrationalised
as a mix of different rationalised systems.
Given the name of the Gaussian Unit in this form, one can find other units.
This is handled by changing the prefix and/or suffix of the GU.
|G_|| Gaussian || ab- || stat- || nen- || _U || (u) || - || -ero || -ade
|M_|| Magnetic || ab- || ab- || ab- || _I || SI || - || - || -
|E_|| Electric || stat || stat- || stat- || _Y || - || -ade || -ade || -ade
|N_|| Nines|| nen- || nen- || nen- || _R || BR || -ero || -ero || -ero
|H_|| Hansen || ab- || ? || - || - || - || - || - || -
|Gaussian|| GU || abampere || abamperade || statampere
|ESU || EU || statampere || statamperade || statampere
|EMU|| MU || abamoere || abamperade || abampere
|HLU|| GR || abampero || abampero || statampero
|SI|| sMI || ampere || ampere || ampere
|Hansen|| HU || abampere || abamperade || ampere
The SI has a UES description of metre-kilogram-second-MI=10**7. The
10**7 appears in the definition of the Ampere, in the force of 2/n Newtons.
When one replaces n to a more suitable value, eg a power of the base, this
is in effect setting MI to some other n, eg MI=120**4 or MI=12**8.
Typically, MI is set to less than the speed of light, such that c=zn,
where z and n are both greater than one. The easy way of handling the
electrostatic system is to use c = n/z, and set MI = n/z².
To fake the transition from emu to MKSA, one should recall that the
metric units are derived from the EMU, for which Q² = LM/n. That is, if
your system does not make n square, you should have an alternate that
does: so in the MKSA, one could easily point to metre-gram-second, which
makes 1 C² = 1 m * 1 g / 10^4, ie 1 C = 0.01 √(m g)
or metre-tonne-second 1 C² = 1 m * 1 t / 10^10 or 1 C = 0.00001 √(m t).
The practical electrical units proceeded the cgs units, and we need to
look to either the metre-gram-second or milimetre-milligram-second for
- UI (1959) *
A set of Imperial conversion factors introduced around 1960,
as a uniform international conversion factors.
UI foot = 0.3048 metres
UI pound = 0.45359237 kilogram
- UK (1922) *
A set of Imperial conversion factors dating from the NPL
measurements of 1922. These served as legal standards until they were
displaced in 1963.
UK foot = 0.91439841/3 metres
UK pound = 0.453592338 kilogram
By Sears, Jolly and Johnson, the yard measured 0.91439841 metres. The
Sears conversion factor used in geodetic surveys is
39.370 146 983 467: unknown basis
39.370 147 000 000: 1 metre = 39.370 147 inches
The pound yielded 0.453592338 kg at the same time.
- UL *
The Imperial conversion factors adopted for the fpsc
UL foot = 299792458/983574900 metres
UL pound = 0.4535923392 kilogram
The light second is fixed to 299792458 metres and 983574900 feet. The
imperial factor is chosen because of its factors.
The pound is chosen because of its factors, and is very close to the
UK conversion factor.
- uncia *
The uncia is a twelfth measure, a weight applied to the linear system.
While both the foot and pound were divided into twelve uncia, the
subsequent history is for them to take different paths.
See inch, ounce
- US (1898) *
The Imperial conversion factors used in the US from the
Mendenhall Order of 1898 until it was displaced by the UI in 1959.
US foot = 12/39.37 metres
US pound = 0.4535924277 kilograms: rounds Broch's pound to 10 decimals.
The different capacity units are discussed under the Imperial system entry.
- US decimal *
A system inspired by the approximation that 1000 oz water is nearly a cubic
foot. This system got dangerously far along the legal road without being
sorted out in precision.
millier \ 10 cwt \ 100 pound \ 10 oz \ 10 dram
mile \ 10 furlong \ 10 chain \ 10 perches \ 10 feet \ 10 inch
bushel = cu ft \ 10 gallon \ 10 pint \ 10 oz
dollar (oz) \ 10 dime \ 10 cent \ 10 mill [money]
The US oz would be somewhere in the range of 436 to 453 grains, and thus
the dollar would be of the order of 5 shillings (a value it had also in WW2).
The system was never formalised, and by the time the great expansion in
the west happened, Gunter's chain had taken seed.
- UV (1864) *
The Imperial conversions that applied during the reign of
Queen Victoria. The values were legalised in 1867.
UV foot = 12/39.37079 metres: Kater's 1816 comparison
UV pound = 7/15.43234874 kilogram: Miller's 1844 value.
The metre of the Archives, yielded 39.37079 inches on Shanksburgh's yard.
Proffessor Miller determined the kilogram to be 15,432.34874 grains,
against the newly constructed pound prototype. The previous standards
were lost in the 1834 fire that destroyed the Houses of Parliment.
© 2003-2004 Wendy Krieger