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- 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/in³ | 5515.3 kg/m³
|
|---|
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