Adventures in non-metric land

Introduction

I have always been fascinated by measuring systems. Especially teh non-metric ones. The most famous is the US/UK "imperial system" (there are slight differences between them, based on a UK pint being 20 fluid ounces instead of 16 fluid ounces like the US pint). But a plethora of interesting measures and units comes from Sweden, where there are at least two distinct non-metric measuring systems, sharing unit names (pre-decimalisation and post-decimalisation).

To make things even more fun, they also share names (at least conceptually) with some of the translated unit names of the imperial system.

Imperial system

Let's start with the imperial system, because it's certainly going to be more familiar to non-Swedes (and, to be honest, probably for Swedes too).

Length

Name	Relation	Metric
Inch	1 inch	0.0254 m
Foot	12 inches	0.3048 m
Yard	3 feet	0.9144 m
Furlong	220 yards	201.168 m
Mile	1760 yards	1609.344 m
Link	0.01 furlongs	0.201168 m
Perch / Rod	25 links	5.0292 m
Chain	100 links	20.1168 m

Area

Name	Relation	Metric
Rood	1 furlong * 1 rod	1011.714106 m²
Acre	1 furlong * 1 chain	4046.856422 m²

Volume

Volume measures are an interesting mess, starting with a difference between the US and UK fuid ounce (fl. oz.).

Name	Relation (UK)	Relation (US)	Metric
UK fluid ounce	1 fl. oz.	0.961 fl. oz.	28.413 ml
US fluid ounce	1.041 fl. oz.	1 fl. oz.	29.574 ml
US pint	16.654 fl. os.	16 fl. oz.	473.184 ml
UK pint	20 fl. oz.	19.215 fl.oz	568.26 ml
US gallon	133.23 fl.oz.	128 fl. oz.	3.785 L
UK gallon	160 fl. oz.	153.72 fl. oz.	4.546 L

The Swedish measures

These units have varied through time, so it is somewhat important to know when a specific measurement was given, if one is interested in an exact conversion.

Standard, national measures were instated in 1665 (with a minor revision in 1735). In 1855, the measurements were decimalised and in 1889 Sweden became metric.

Most imperial/US units do not have translations in Swedish. Some, unfortunately, do, making things even more confusing. The ones that do are the inch (called tum), the foot (called fot) and the fathom (called famn). It will soon be shown why this is unfortunate.

Pre-standardisation

Name	Description
Fingerbredd	The width of a finger, usually the middle finger.
Tum	The width of the thumb.
Tvärhand	The width of the hand's four fingers, held tightly together.
Fot	The distance from the heel to the tip of the big toe.
Aln	The distance from the elbow to the tip of the pinkie.
Famn	The distance from the tip of the left middle finger to the tip of the right middle finger, when both arms are stretched as far as they can be.

Pre-decimalisation

Distance measures

Note that the "mil" length unit varied throughout Sweden, until 1669, with the Finnish mil being the shortest at ca 6 000 metres and the dalamil ("dalamilen") the longest at around 15 000 metres.

Length measures
Name Relation Metric Notes

Fingerbredd N/A 0.0185 m

Tum 1 tum 0.0247 m This is a close cognate to the imperial inch

Tvärhand 4 tum 0.0989 m

Kvarter 6 tum 0.1484 m

Fot 12 tum 0.2968 m This is a close cognate to the imperial foot

Aln 24 tum 0.5938 m In actuality, the aln was the base unit that all other length units derived from. Its plural form is "alnar".

Steg 1.5 alnar 0.891 m This is probably the closes you get to a yard, but there is no naming confusion, the unit's name means "step"

Famn 3 alnar 1.78 m This is a close cognate to the imperial fathom.

Fjärdingsväg 4500 alnar 2672 m This is a fourth of a mil

Mil 18 000 alnar 10688 m

Length measures
Name	Relation	Metric	Notes
Fingerbredd	N/A	0.0185 m
Tum	1 tum	0.0247 m	This is a close cognate to the imperial inch
Tvärhand	4 tum	0.0989 m
Kvarter	6 tum	0.1484 m
Fot	12 tum	0.2968 m	This is a close cognate to the imperial foot
Aln	24 tum	0.5938 m	In actuality, the aln was the base unit that all other length units derived from. Its plural form is "alnar".
Steg	1.5 alnar	0.891 m	This is probably the closes you get to a yard, but there is no naming confusion, the unit's name means "step"
Famn	3 alnar	1.78 m	This is a close cognate to the imperial fathom.
Fjärdingsväg	4500 alnar	2672 m	This is a fourth of a mil
Mil	18 000 alnar	10688 m

Area measures

The area measures were primarily used in measuring fields and were primarily relations between a volume measure and how large a plot of land one of those volume measures of seed would cover.

Area measures
Name	Relation	Metric
Kannland	1000 kvadratfoot 1/56 tunnland	88.15 m²
Kappeland	1/32 tunnland	154.3 m2
Spannland	1/2 tunnland 16 kappeland 28 kannland	2468.3 m2
Tunnland	2 spannland 32 kappeland 56 kannland	4936.6 m2

There were also monetary area measures, these are based on the nominal value of a given amount of land.

Volume measures

Volume measures were different between dry/solid (powder or grain) measures and liquid measures. In the following table, I will present them as side-by-side as I can. Any measure that is only applicable for one of the categories will be marked as N/A for the non-applicable category. N/AN/A

Volume measures
Name	Dry		Wet		Notes
Name	Relation	Metric	Relation	Metric	Notes
Skäppa	varies	varies	N/A	N/A	This measure was in use from the 13th century until it was outlawed in 1735. Its actual measure varied across Sweden
Jungfru Ort	N/A	N/A	1/4 kvarter 1/16 stop	8.2 cl	The measure was frequently made as a truncated cone and could this be likened to a woman in a long skirt ("jungfru" can be translated as 'virgin')
Kvarter	N/A	N/A	4 jungfru 1/4 stop	32.7 cl
Stop	N/A	N/A	4 kvarter 1/2 kanna	1.3 l	This measure is probably one of the more well-known "old measures" and in modern Swedish is thought to correspond to a large serving of beer.
Kanna	1/7 fjärding	2.617 l	2 stop 1/12 fjärding	2.62 l
Kappe	1.75 kannor	4.58 l	N/A	N/A
Fjärding	4 kappar 7 kannor	18.32 l	12 kannor 1/4 tunna	31.4 l
Ankare	N/A	N/A	1/4 åm 15 kannor	39.25 l
Spann	1/2 tunna 4 fjärding 16 kappar	73.28 l	N/A	N/A
Tunna	2 spann 8 fjärding	146.6 l	4 fjärding 48 kannor	125.6 l	The dry measure is a "loose measure", for a "firm measure" it should have 4 loose kappar added and then totals 164.9 l. The distinction between loose and firm measures exist throughout the dry measures, with the same relations.

Weights

Due to wanting to get this finally published, I have elided the weights section, since "weight" is a complicated matter, only made worse by the fact that quite a few of the weight units have different weights depending on what is supposed to be weighed (the uns is for gold 27.9 g, for silver 26.3 g and as a medicinal measure 29.69 g; it corresponds roughly to the Imperial ounce).

Sources

http://www.algonet.se/~hogman/slmatt.htm
Wikipedia: Imperial units

This is one of Ingvar's essays