-: P :-

Glossary: Home Tables A B C D E F G H I J K L M N O P Q R S T Th U V W X Y Z

paper-weights *
A measure of paper area-density, eg pounds (per folio-ream) or grams per square metre.
      A gram per square metre corresponds to 500 grams per ream of A2 sheets. The unit corresponds to a micron depth of water.
gsm weight width bredth name notes
0.697 489 662 1 lb 4 ft 6 in 3 ft gr/sq ft known unit
1.000 000 0 500 g 1.1892 m 0.84089 m gsm defined in area
1.000 000 0 1 lb. 37.5 in. 37.5 in. gsm imperial units
1.058 823 5
parcircle *
A unit equal to 1/2π AU, or 79.420226 light seconds. This is the radius of a circle having a circumference of 1 AU or 499.012 light seconds.
      In a given measurement circle, if a circle is divided into k seconds, the parsec is k parcircles. The unit is relatively base-free, and is useful for comparing similar sized units.
      1 astronomic unit = 2π or 6.283185307 parcircles.
      1 terametre = 1E12 metre = 41.999 892 470 parcircles
      1 light year = 365.25 light days = 397349.660 parcircles
      1 H8 UL feet = 550441.807686 parcircles
      1 parsec = 1296000 parcircles
      1 twelfty-parsec = 1728000 parcircles.
A Practical system based on powers of 60.
Length pace quadrant / 60^4, = metre / 1.296
Mass baros kilogram * 1.296²
Energy Joule unchanged
Time second unchanged
Current ampere unchanged. All SI units unchanged except tesla
One can experiment with an L-style rationalisation by treating the baros as a slug-like unit, = g-mass, and setting gravity to 4pi. The units Coulomb, Ampere, Ohm, Henry, are reduced by 4pi, and the Farad and Siemens are increased by 4pi.
Perm *
An imperial unit for fluid permeability, = gt /hr ft² inHg = -10. The unit gives 57.452642 E-12 s/m, or 1/57.948016/c. A unit perm.inch is given also as 1 inch by a perm, as 1.459297 e-12 s
Pi *
The circumference of a unit-diameter euclidean circle.
      The value is near 3.1415926535897, but for convenience, it has been approximated as shown in the footnote.
(@mgpicul picul
A weight, as much as a man can carry on a sholder pole, y 100 caddies, or sixty chogs, or half a seam. Where a seam be 300 lbs, then a caddy is 160, a caddy is then 216 drams, an tael is 13.5 drams or 40 scruples or 800 grains. A mace is then 80 grains, a cashereen is 4/5 grains, or 19,2 mites.
pidgin Unit *
Pidgin comes from the chinese for trade. Just as one might have a pidgin language, one might have a pidgin weights and measures, for the use in the bazaars of asia.
      Pidgin units refer to systems of local denominations, but defined in the measures of a foreign, usually colonising, power.
      In india, these were used, as railway or government weights.
ruttee 1/7680 1 7/8 gt 1/128 ledd
masa 1/960 15 gt 1/16 ledd
toli 1/80 180 gt 3/4 ledd
seer 1 30 oz tr 60 ledd
maund 40 100 lb tr 80 lb
In the straights settlement, and points beyond, these weights are used.
cash 1/16000 7/12 gt 36 mites
ticle 1/80 1/60 lb avoir 120 gr
tael 1/16 1/12 lb avoir 600 gr
caddy 1 1 1/3 lb avoir 40 ledd
picul 100 133 1/3 lb avoir 1 1/9 cwt
prat *
A name being suggested for a twelftieth part. It derives by metathasis of the word part.
prefix *
A prefix applied to a unit generally modifies it in size, but keeps constant some derivation.
      In the metric system, a prefix creates multiples and submultiples of the unprefixed unit, eg kilo- = 1000x + gram unit of weight.
      In the Kenneley and UES systems, a prefix is used to create a like unit in a different set of base units, eg ab- emu + volt = voltage unit. The UES augments the Kennerley prefixes with suffixes.
prism product *
A coherent set of units based on the measure polytope of unit size. Such scale is the common scale in use.
      prismatolatric or linear
      prismatohedric or square
      prismatochoric or cubic or cubical
      prismatoteric or tesseractic or biquadrate.
proportional *
A construction based on extant segments, not necessarily divided in that way. For example, in Germanic traditions, a hundredweight is 120 pounds. One might therefore suppose a proportional pound, given a hundredweight, as 1/120 of it, even though the natural tradition is tho divide elsewise.
      The avoirdepoise grain
      The practice is to a large extent a feature of the Roman and Latin systems, where units had standard divisions.
PR conversion factors*
A set of conversion factors from the Pre-metric parisian system to the metric system. On such basis was the prototype metre and kilogram wrought.
      A Metre = 443.296 lines, where 144 make the foot and 864 the toise.
      A Kilogram = 18827.15 grains, where 9216 make the pound or livre.
Practical Units [Electricity] *
The set of electrical units for practical applications.
      Until 1866, the units were defined in terms of a construction, such as a resistanace equal to a mile of Nr 8 coper wire. Because of international trade, it was decided to formalise a fixed set of units.
      The decision was taken to replicate decimal multiples of the theoretical electromagnetic units, the sizes chosen to be nearest some existing units. All units would have proper names, but the construction would follow the former practices.
      The named units were:
ohm chosen to be near a resistance of a metre long column, of cross section 1 sq millimetre. This was implemented in a v-shaped groove.
volt chosen to be near a Daniels cell
ampere volt / ampere, later defined in terms of the silver faraday
coulomb ampere second
farad coulomb per volt
henry formerly quadrant = ohm second
Until such times as one could devise a better way, the style was to define prototypes, usually in more refined ways. For example, the Ampere became defined in terms of silver faradays per day.
      The units slightly disagree with what the intension should be, and it is better to indicate the units as iV for international volt.
      The electric units, rated originally as free-standing (like mile, hr, mile/hr), were ampere, volt, watt, ohm, mho, coulomb, farad.
      James Clarke Maxwell showed that these were the EMU of a system with a lenth unit of 10,000 km, and mass of 0.00001 micrograms.
      Gustav Mie produced a revised set of formulae, explicitly making the constants non-unit, to the rule of cm, 10t, s, MU=10^10.
      Professor Giorgi produced a system based on metres and the practical units, giving the metre, kilogram, second, MU=10^7
      The Hansen units, widely used, is mixed using practical electric units and cgs-emu. unit name description
gauss A measure of magnetic flux density B = 0.000 1 tesla
maxwell A cgsm unit of magnetic flux, also height line
oersted a cgsm unit of magnetic field intensity H
gilbert a unit of magnetic potential = 10/4pi Amperes
Contary to later beliefs, these were never used across the full dimensionality. eg one never measured electric currents in gilberts, although this does have that dimensionality in SI. [cf ICT]
Proto-Metric *
The metric system, as originally planned. History has taken its toll.
      In its original form, the greatest portion of measures were meant to fall in the range of milli- to kilo- units. Prefix denominations were provided for each of the six decimal powers in this range.
      The final column shows the Wilberforce names for the dm.kg system. Unlike the metric, it is coherent, and takes exponential numbers, eg Linn-threes, not kilolinn.
Angle Degree 400 make the circle. (unit renamed grade) Gradd
Length Metre 1000 metres make 0.01 degree of earth circle. Linn
Area Are square of 10 metre side. Arr
Volume Stere cubic metre, eg for firewood and water Soll
Capacity Litre 0.001 cu metre, for liquid and dry capacities. Capp
Course Weight 'grave' Litre of water. Pound-like unit Pondd
Fine Weight gram 1000 make the course-weight unit Pondd
Money franc 0.1 grams of silver bullion Monn
After the revolution, the Systeme Usuele was used for trade in the markets. By the time that it was decided to abandon the system-usuele, and use the metric system, the notion of having separate systems for fineweight and coarseweights had fallen out of favor, and the fineweight system was extended upwards.
      The original time system was a decimally divided day (day \ 10 hours \ 100 minutes \ 100 seconds), but the system works better when the day and circle are taken as equal, and the day is divided into 40, eg day \ 40 kilobel \ 1000 bels \ 1000 millibel. One then has a m/b and a km/kb as identical.
      The original system included a calendar. It is a mistake to tie a calendar to the measurement system, as the french soon discovered.
Prussian System *
A system used in the North of Germany until the unification of 1871. The units in part seem to date back to the Hansiatic league. The English version is based on a pound found in the Tower of London, and so called.
      A foot, rated at 0.313 857 metres or 139.13 French Lignes
      A pound, rated at 0.466 711 kilograms.
      A quart, rated as 1/27 cubic feet, prussian measure.
A prussian hundredweight was 110 pounds, not 120, apart from this, one has a system similar to the hansiatic one. The prussian foot was used in various places, including Scotlant, but the length was never set to be exact anywhere. It was for this reason that decimalisation to metric was adopted in the Scandinavia.

© 2003-2004 Wendy Krieger