In advancing our knowledge of ancient science and technology our greatest need is for accurate accounts of technical processes, based on detailed study of all the available evidence, both literary and archaeological, and on the rigorous exclusion of sweeping generalizations in the discussion of questions where evidence is scanty and interpretation uncertain.The discussion that follows is a small contribution, based on close study of the evidence, towards the solution of a complex of problems which are of considerable importance to the student of Roman history. Unfortunately, statistical information on crop-yields is wholly lacking, and the researcher is reduced to the task of sifting a variety of scattered evidence from different periods and areas of cultivation.
