Nineteenth-century American farmers left a record both in the historical documents and in historical statistics. The statistical record shows a rapid settlement of the land, a growth of output from three- to tenfold in the major crops and animal products between 1840 and 1910, steady or slightly rising crop yields in old and new regions alike, and a marked fall in the labor time required per acre and per output unit in many important farm tasks. It shows also, when spread out over the map of the country, a shifting in the location of various crops and a settling down, toward the end of the century, into the present pattern of regional specialization. Analysis of this statistical record indicates that it was produced through uncounted acts of innovation, ranging from small adaptation of practices and genetic materials in new localities to “revolutionary” inventions in equipment. This paper seeks not to state the events in this record of innovation, but to ask why it was produced by these people in this time and place and how they worked together – manning positions in a bit of social machinery – in producing it. To answer these questions, we must go beyond the statistics to the other kind of historical debris – the record of the artifacts and the writings of the farmers and those associated with them.