It seems likely that the North German acker of 160 square ruthen came to Northern France with the Franks and the Normans, that it became the Acre de Normandie of 160 square rods, the length of the rod becoming changed by the influence of the French standard of 6 _aunes_ = 24 Roman feet. This length of 24 feet passed, under Norman influence, to Cheshire, becoming the local rod of 8 yards or 24 English feet.
The rod of 6 _aunes_, French ells, passed to Scotland as 6 ells, but 6 Scots ells = 18 Rhineland feet.
The North German acker or morgen is 160 ruthen. Why? It may be presumed that, on the sexdecimal system dear to the bucolic mind throughout the world, it was 16 times an original unit of 10 square ruthen, of 16 feet square, analogous to the Greek plethron of 10 square kalamoi and to the Provençal _cosso_ of 10 square fathom-rods. There is still extant, in North Holland, the _snees_, snick, or score, of land, = 20 square roede.
The Austrian joch is 1600 square ‘klafter’ of 6 feet = 1·42 acre.
There are 1600 square rods in our square furlong, the original square unit of which the acre is a one-tenth slice.
In Provence, the people, long under Roman influence, are yet much more Greek than Roman, and there is not a trace of any Roman standard among their weights and measures. There the greater land-unit is the saumado of 1600 square cano of 6 feet. It is divided in two ways: (1) on the sexdecimal system,[20] (2) into 160 cosso, each of 10 square cano.
Concordantly with the sexdecimal system of corn-measures into 4 sesteirado, or 8 eiminado. See Seed-measures in Section 10.
It seems as if the 1600 small units in our square furlong, in the Austrian joch, in the Provençal saumado, come from an extension of the sexdecimal multiple 16 to 160 and 1600.
‘Customs of places doe differ; for in the Dutchy of Lancaster a knightes fee containeth foure hides of land, every hide foure ploughlands called in latine carucata terræ, and that is quantum aratrum arare potest in æstivo tempore, and that is (as I take it) which is in the North parts called an Oxegange. And every ploughland or carue is foure yard land which in latine is called quatrona terræ; every yardland thirty acres, halfe a yard land in some places in the West is called a Cosset, half a Cosset is a Mese which containeth about 7-1/2 acres. But commonly a carue or plow-land containeth a hundreth and twenty acres; a hide of land 480 acres and every knightes fee 1920 acres. But after some computations, a knights fee containeth five hydes of land, every hyde foure yard land, and every yard land twenty foure acres.’ (‘The Surveior’s Dialogue,’ by J. Norden, ‘at my poore house at Hendon, 27 Martis 1610.’)