“Why, even though the yard an acceptable unit of distance, height is invariably measured in feet?” I find this question intriguing, especially as it appears that the yard was the dominant unit in measuring length as far back as the thirteenth century. To answer the question, then, one would appear to have to go back to mediaeval usage. In the absence of sources documenting the early use of the foot in measuring heights I shall present some observations and make a hypothesis.
Different units of measurement: some observations
- They are important for, and reflect the needs of, trade and commerce.
- They vary between trades or areas of activity — horses are measured in hands, race tracks in furlongs, chemists used to weigh in grains, farmers in bushels. Significantly, depth (with its relation to height) was measured in fathoms, rather than yards. Even today distances and speeds at sea are measure in nautical miles and knots!
- A single measure was normally used, rather than the combination common today. For example, the Wikipedia entry on yard, quoted above, makes it clear that the introduction of ‘inches’ with yards was a legal measure to replace the black-market ‘handful’, rather than a response to a need to subdivide the unit. Halves and quarters of a single unit would be used.
- A rationale for the choice of unit of measurement is that it should be small enough that one did not have to subdivide it into more than halves or quarters, and large enough that one does not have to use numbers containing more than two digits — it has to be usable by ordinary people.
- The 13th century Statute of Ells and Perches standardization of the units of length was a response to local differences in usage (especially of the yard). It would be naive to think that local differences from the standard did not persist. If trade were local, this would hardly matter.
Height: a Hypothesis
My hypothesis is based on the premise that the commercial and practical need to measure height was much less than that to measure length — I can think of that might have been sold on the basis of height. I would suggest that the activity that required this, usage was architecture — probably civil/military, although perhaps also naval. Christopher Wren’s plans in the seventeenth century contain measurements in feet, and I suggest this is a continuation of practice that well may have been first adopted in Anglo-Norman times.
Why would architects have adopted feet, given that they were specifying length and breadth as well as height? One might argue that height was particularly important, and feet were already in use for measuring height. I do not know whether either of these assertions is true. An alternative is that the yard was much more ambiguous than the foot. Although the master builder may have adhered to the official standard, the workmen executing his plans might have had their own yard. Finally, it may have just been that the yard was too long for the detail required, and the foot and its half and quarter were more convenient.
It would be nice to know…
My hypothesis is difficult to prove, but it would be helpful to have more facts about the historical measurement of height:
How was height specified in the oldest historical documents in English that mention it? Was it indeed a concern — did people care about the exact height of a tall or small individual or of geographical features such as mountains?
What units are used in the oldest English architectural plans that specify them?
Am I right in saying that different units were not mixed? When were measurements first specified in a mixture of yards and feet, for example?
Footnote: Different meanings of the word ‘yard’ as a unit of measurement
According to the first edition of The Oxford English Dictionary (OED) ‘yard’, as used for a unit of length (and in several related meanings), is derived from a word which in different Germanic languages has the sense of pole, rod, prickle (and hence its obsolete use defined in OED-11 — “virile member, penis”). This is distinct from the origin of the word ‘yard’ with the general meaning of “inclosure” (sic).
As well as its equivalence (or that of the ell) to three feet, specified in the thirteenth century (OED–9, first example cited using the designation, ‘yard’, in 1377), another meaning of yard or landyard (OED–8) is given as “a unit of linear measure equal to 16½ feet…(but varying locally).” The OED cites a source as recent as 1856 which states “As a linear measure the yard varies considerably in different parts of the kingdom; at Hereford the landyard is 3 feet, at Saltash 16½ feet; at Falmouth and Bridgend 18 feet; and at Dowanpatrick 11 feet.”
A definition for this derivation of ‘yard’ in terms of area is also given in OED-10: “An area of land of varying extent according to the locality, but most frequently 30 acres” with usage dating back to 688–95.”