substances of which it is composed, as a chalky soil, a gravelly soil, or what ever else may be its distinguishing quality.  And as there are different varieties of soil so each variety may be subdivided according to its quality, as, for example, a rocky soil is either very rocky, moderately rocky or hardly rocky at all.  So three grades may be made of other mixed soils.  In turn each of these three grades has three qualities:  some are very wet, some very dry, some moderate, These distinctions are of the greatest importance in respect of the crops, for the skilled husbandman plants spelt rather than wheat in wet land, and on dry land barley rather than spelt, in medium land both.  Furthermore there are still more subtle distinctions to be made in respect of all these kinds of soil, as for example it must be considered in respect of loam, whether it is white loam or red loam, because white loam is unfit for nursery beds, while red loam is what they require.  But the three great distinctions of quality of soil are whether it is lean or fat, or medium.  Fat soils are apparent from the heavy growth of their vegetation, and the lean lie bare; as witness the territory of Pupinia (in Latium), where all the foliage is meagre and the vines look starved, where the scant straw never stools, nor the fig tree blooms, while for the most part the trees are as covered with moss as are the arid pastures.  On the other hand, a rich soil like that of Etruria reveals itself heavy with grain and forage crops and its umbrageous trees are clean of moss.  Soil of medium strength, like that near Tibur, which one might say is rather hungry than starved, repays cultivation in proportion as it takes on the quality of rich land.”

“Diophanes of Bithynia,” said Stolo, “was very much to the point when he wrote that the best indication of the suitability of soil for cultivation can be had either from the soil itself or from what grows in it:  so one should ascertain whether it is white or black, if it is light and friable when it is dug, whether its consistency is ashy, or too heavy:  or it can be tested by evidence that the wild growth upon it is heavy and fruitful after its kind.[65] But proceed and tell us of your third division, which relates to the measurement and laying out of the farm.”

Of the units of area used in measuring land

X. Scrofa resumed:  “Every country has its own system for measuring land.  In Further Spain the unit of area is the jugum, in Campania the versus, here in the Roman country and among the Latins it is the jugerum.  They call a jugum the area which a pair of oxen can plough in a day.  The versus is one hundred feet square:  the jugerum is the area containing two square actus:  the actus quadratus or acnua, as it is called by the Latins, measuring 120 feet in width and as much in length.[66] The smallest fraction of a jugerum is called a scripulum