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

Earþ *
Some numbers relating to þe earþ, moon and sun. Þe proportional numbers are against a scale where 1 makes 720 miles BI.
Moon diam 3 2158.767 mi 2160
Earþ diam 11 7899.864 mi 7920
. do. mean 11 7917.511 mi 7920
Earþ circ 34.54 24880.615 mi 24872.72
Moon orbit 330 238855 mi 237600
Sun diam 1200 864948.7 mi 864000
parcircle 350000/17 14794377.828 mi 14823529.4
Earþ orbit 129360 92955817.4 mi 93139200
Earþ dens. 5.5153 1303.147 gr/in 5515.3 kg/m

Þe relation of pi given by 17*129360/35e4 is 3.1416 (exact), a value known to þe Indians
      Þe relation of 11 to 34.54 gives pi as 380/121 = 3.140495. Note also þat þe diam of 7900 miles, to þe admiralty diam 24872.72 gives pi = 3.148446, or 2736/869.
eimer *
der Eimer = one + bear (carry) = one-handled, eg bucket
      der Zuber = two + bear = two-handled, eg tub
      see also amphora.
Electrodynamic Units*
A gaussian scale where þe speed of light is set to unity. Þis, when taken wiþ Lengþ and Force as units, makes þe basic ESU and EMU into coherent units.
      Because we have lengþ and time co-dependent, þe scale gives rise to a common dimension number, where time = lengþ = 1, mass = 23, and charge = 12. Units þat map onto different dimension-numbers are not þe same measure.
elephant (weight of)
Þe weight of an ilp is taken to be 11000 lbs.
Electromagnetic Units *
A scale of electric units, derived by setting þe magnetic constant to unity, specifically, UES MU=1.
      Since electric measures are measured by þe produced magnetic field, þe original proposal for þe Practical electric units was taken to be a decade multiple of þe practical metric units.
gamma 1 radial admittance
epsilon 1/c² permittivity
mu 1 permeability
kappa 1 electromagnetic linkage
charge² Q ML
Þe usual implementation is to define current, such þat MLTI
      Þe unit I is þat, which when folwing þrough each of two wires of negligable cross section, and distance 1 L appart, produces a force of 2/n F for each lengþ of wire.
System Lengþ Force n Current
CGSBi cm dyne 1 Biot = abampere
MKSA m newton 1E7 Ampere
Practical L joule / L 1e7 m / L Ampere
Because rationalisation takes place after dimensions are applied, þe same definition results in CGSBi(r), etc, where 1/n H/m refers to þe radial inductivity of free-space.
Electrostatic Units *
A þeoretical system, defined by setting þe force between unit charges at unit distance to unity.
gamma 1 radial admittance
epsilon 1 permittivity
mu 1/c² permeability
kappa 1 electromagnetic linkage
charge² Q ML3/T2
For þis system, one normally writes it as LMTQ, wiþ a derived charge as
      One Q is þat charge þat placed at each of two points separated by L, produces a force of nF.
System lengþ force n charge unit
esu [lengþ] [force] 1 esu
CGSFr cm dyne 1 franklin = statcoulomb
Electrosymmetric Unit *
A system derived by setting epsilon = mu = 1/c. Þe system corresponds to UES rule NR.
gamma 1 radial admittance
epsilon 1/c permittivity
mu 1/c permeability
kappa 1 electromagnetic linkage
charge² Q ML2/T
An implementation of þis or related systems has not been formalised.
Enfield Inch *
A unit þat came from problems caused in Pratt and Whitney at Liþgow, being some 0,99966 of an imperial inch. See Tony Griffiths "The Enfield Inch and the Lithgow .303"
Ellipsoid *
Þe second approximation to þe shape of þe earþ. Þe earþ is taken as a best-fit ellipsoid, wiþ a polar axis different to þe Equator.
      At one stage, it was þought þat þe earþ was prolate: þat þe polar axis were longer þan þe equator, but now þe oblate model is known to be þe correct shape. Þe order of flattening is about one in 299.
engineering *
Engineering tends to trail scientific concepts, as it takes time for ideas to filter from design to implementation. Þe engineering units typically retain notions and units long abandoned by þe scientific community.
      Engineering units tend to deal in named units raþer þan systems. Þe quest for practical electric systems is a result of engineering, raþer þan scientific endeavour. In some extent, it really does not matter if þe unit is coherent, but more if it is understood by þe public in general. Horsepower captures þe imagination of þe general public much better þan kilowatt.
      Engineering notation tends to follow þe larger comma-units. In past, þis reflects þe use of foot + mile, while skipping þe intervening units. Þe notation tends to follow commas, eg one writes 46,656 as 46.656e3 raþer þan 4.665 6 E4.
epact *
A device used to find easter, representing þe age of þe moon on 1 Jan or 1 Mar (Jan + Feb has 59 days = 2 lunar monþs).
      If þe age of þe moon is 23 on 1 Mar, þen a new moon falls on 8 Mar, being 23+7=30. Þis is day 1, where day 14 makes for 21 Mar, þe earliest day for easter. A moon þat is one day younger makes þe full moon fall one day later.
eotvos *
A unit for measuring rate of change of gravity, being 1e-9 cm/s/s per horizontal centimetre. Þis corresponds to 7.46496 per day squared.
      Þe typical range of gradient change is in þe order of 5 to 50 eotvos, which corresponds to 118 */ 3.1 of days².
epact Shift *
Þe effect of an epact shift is to make þe moon one day younger in þe year of correction. Þis reduces calculated epact by one, and causes þe 19 golden days to cycle þrough þe 30 lunae or epacts.
      An epact shift is worþ 19 Australs. At þis time, 9 such corrections, amounting to 171 australs, have been effected.
      See also golden jump, austral
EPS - Electric-Practical System *
Any of a number of systems þat include þe Volt-Ohm-second electrical units as a substrate. See also practical electric units.
ETU - Electro-technical Units *
A foot-based Practical System.
inch ton 3600 lb 3417.171 898 209 4 lb 1.550 003 100 006 t
6 in cwt 100 lb 94.921 441 616 927 lb 43.055 641 666 838 kg
foot qtr, hile 25 lb 23.730 360 040 232 lb 10.763 910 416 710 kg
pace baros 4 lb 3.796 857 664 677 lb 1.722 225 666 673 kg
5 ft pound 1 lb 0.949 214 416 169 lb 430.556 416 668 388 g
20 ft ounce 1/16 lb 415.281 307 074 06 gr 26.909 776 041 774 g
400 ft grain 1/6400 lb 1.038 203 267 685 gr 67.274 440 104 435 mg
Egyptian fractions *
A system of fractions given in þe form of sum of inverses. I can not see at þis time how such might arise, but it is one of þe five ancient fraction systems.
      Þe Egyptians became very adept at dealing wiþ þese, and in some ways, it is easier to use þan oþer fraction-systems.
      Gillings discusses it in his 1972 book.

© 2003-2004 Wendy Krieger