Now it happens that such an instance is at hand, affording every opportunity for examination under the most favourable circumstances possible. We find it in the ancient Welsh laws, representing to a large extent ancient Welsh traditions collected and codified in the tenth century, but somewhat modified afterwards, and coming down to us in a text of the fourteenth century. In these laws is much trustworthy evidence from which might be drawn a very graphic picture of the social and economic condition of the unconquered Welsh people, at a time parallel to the centuries of Saxon rule in England. And amongst other things fortunately there is an almost perfect picture of the method of ploughing. Nor is it too [p119] much to say that in this picture we have a key which completely fits the lock, and explains the riddle of the English open field system. For the ancient Welsh laws describe a simple form of the open field system at an earlier stage than that in which we have yet seen it--at a time, in fact, when it was a living system at work, and everything about it had a present and obvious meaning, and its details were consistent and intelligible. Let us examine this Welsh evidence. «The Welsh erws, or acre strips.» «Divided by turf balks.» Precisely as the modern statute acre had its origin in the Saxon _æcer_, which was an actual division of the fields, so that the Saxon _æceras_ were the strips divided by balks--the _seliones_--of the open field system; so the modern Welsh word for _acre_ as a quantity of land is '_erw_,' and the same word in its ancient meaning in the Welsh laws was the actual strip in the open fields. This is placed beyond a doubt by the fact that its measurements are carefully given over and over again, and that it was divided from its neighbours by an unploughed balk of turf two furrows wide.[146] «Measured by a rod.» The Welsh laws describe the primitive way in which the erw was to be measured. In one province this was to be done by a man holding a rod of a certain length and stretching it on both sides of him to fix the width, while the length is to be a certain multiple of its breadth.[147] In other provinces of Wales the width was to be fixed by a rod equal in length to the [p120] _long yoke_ used in ploughing with four oxen abreast.[148] The erw thus ascertained closely resembled in shape the English strips, though it varied in size in different districts, and was less than the modern acre in its contents. Next there was, according to the Welsh laws, a certain regulated rotation of ownership in the erws '_as they were traversed by the plough_,' resulting from a well-ordered system of co-operative ploughing. In the _Venedotian_ Code especially are elaborate rules as to the '_cyvar_' or _co-aration_, and these expose the system in its ancient form actually at work, with great vividness of detail. «Team of eight oxen in the co-aration.»