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Acres, Roods and Perches - or Poles?

Detail from an 1826 survey of Waltham Abbey, giving areas in Acres, Roods and Perches.

In fact, the terms Poles and Perches were interchangeable; both referred to the smallest standard unit of area (5 yards x 5 yards) in the Acres - Roods - Perches system, primarily used for measuring and sub-dividing fields and land. The word Pole comes from the wooden pole used to measure out its sides, which was both long enough for a ploughman to prod the oxen in the front row of his plough-team with, and short enough for the ploughman's boy to be able to carry it. The alternative Perch might have derived from the pole being balanced on the boy's shoulder, a bit like a bird sitting on a branch.

Just to add more confusion, this pole was also sometimes called a rod, and the Rod also became the standard unit of length for such things as shop frontages when a new street was being laid out. In the same way, the two terms Rod and Rood could also be confused - especially when old spelling habits are considered. Roods were usually a unit of area, equal to 40 Perches (or Poles or Rods - properly speaking, Square Rods). Unfortunately, however, there was also a little-used unit of length called a Rood, which was either 7 or 8 yards, or (occasionally) the same as a Rod! Better give up now!

The term Rood is mostly applied to church features, as it means cross. It's an old English word which the Anglo-Saxons seem to have brought with them; it also exists in Old Frisian and Old Saxon (where it meant 'gallows'), Old High German ('rod or pole'), Old Norse ('oar'), and even Old Slavic (' the shaft of a lance'). From this range of meanings we can easily see why Rood could be used either for a length or for an area - or rather (the square of) a length.

Its use within the A.R.P. system may derive from it being a quarter of an acre - in other words, an acre cut into four by making two slices in the form of a cross. This very act of division could even have had religious significance - perhaps the field was being given a blessing by being 'crossed' as the land was being divided amongst the villagers, presumably as it was being cleared of forest and put to agricultural use for the first time.

Closely related to the Rood is the Furlong, which was originally a 'furrow-long' or 'the length of a furrow,' the length in question being 40 Poles or 220 yards (though doubtless it was longer in the morning than it was in the evening, when the oxen were getting tired!). An area 4 Poles wide by 40 Poles (one furrow-length) long, was considered to be the amount of land that one plough-team (a ploughman, his boy, four pairs of oxen and a long stick) could plough in the daylight hours of one day. This area is referred to as an Acre, which term derives from an early French word for 'field.' (The word 'agriculture' has a similar origin - it means 'field culture').

True, the standard representation of a Rood is not square-shaped, neither is the Acre from which it is cut; they both (usually!) measure 220 yards (40 Poles, or 1 Furlong) in length, and 5 yards (1 Pole) or 22 yards (4 Poles) in width, respectively. Hence the act of division will not have been in the form of a cross. But this is a mathematical textbook synthesis of the relationship between the areas, not what happened 'in the field' so to speak, where fields were measured out with a known length of chain, and were thus very fluid in shape. Even though ploughing does tend to be done in roughly parallel lines,the edges of the fields inevitably consisted of curves and odd shapes. Maybe division by four in itself, regardless of the pattern of cuts, held spiritual overtones, similar to the axes of a church for example..

Although smaller areas, subdivisions of the Rood, were more often measured out using the Pole (a wooden pole being much cheaper and easier to come by for the average farmer than an expensive precision-made chain), the use of chains became so popular that the Chain also became an official unit of length - but if you see Chains mentioned on a map-scale, make sure you check the map's context, for there were many different standard lengths of Chain, such as the Engineer's Chain (sometimes 50 feet long, sometimes 100).

The Chain which you are most likely to find used in English surveys and maps however, is properly called Gunter's Chain, named after Edmund Gunter (1581-1626, a Hertfordshire-born astronomer-mathematician of Welsh extraction, as his surname reveals!), which is 4 Poles or 22 yards in length. So why did Gunter's Chain take off so successfully? What was wrong with Yards and Poles anyway? They couldn't measure area, that's what. Chains could.

Remember that an Acre is 22 by 220 yards; by using Gunter's method this becomes 1 x 10 Chains. Gunter developed this idea further by giving his chain exactly 100 links. This meant that a piece of ground of any shape could be measured in Chains and tenths (i.e. groups of ten links) - and in hundredths if need be; if the length and width are then multiplied together, the result simply divided by 10 equals the size in Acres!

What Gunter had done was to devise a clever way of calculating areas in the familiar language of ancient units, by using the simplicity of the decimal system - its first officially accepted use in England! (Or it is? Answers on a postcard please!)

Although the Chain has long been obsolete and was always a bit specialist in this country (being a form of calculation rather than a unit of length), it is still very much in current use in the U.S.A., being the standard method of measuring the acreage of all American public lands.

Rods, Roods, Perches and Poles were all abolished by the Weights and Measures Act of 1963, though they are still used in a sense - in cricket, wickets have been placed 22 yards (4 Poles) apart ever since 1744, and the numbered posts on racecourses count how many furlongs away the winning post is. We also still use the expression 'Oh, we're poles apart!', meaning 'there's a lot of distance or difference between us.' We won't mention 'spare the rod and spoil the child' - not very P. C. these days!

Furlongs and Acres, like their larger cousins Virgates, Hides and Hundreds, originally varied considerably in size, being measurements of land-quality (ploughing difficulty) or value (fertility) rather than physical dimension. But Acres (and by consequence their smaller divisions) became standardised units of area under an Act passed by Edward I, and are still a legal unit in England today - though they are now rarely used officially (except by estate agents) and are to be repealed in the near future.


Copyright Waltham Abbey Historical Society, 2007.