The mobility of farm servants set them apart from all others, both literally (because mobility broke those social bonds that depended on contiguity) and conceptually (because no other group shared this characteristic movement). The militia lists of Hertfordshire should have been an excellent source for the calculation of the distance travelled between hirings, because the lists are continuous from 1758 to 1765 and include almost all Hertfordshire parishes. So one parish, Westmill, was chosen as a base for 1758 and 1759, and the names of the eighteen male servants of Westmill in those years were sought in the subsequent lists for Westmill and fifteen surrounding parishes. By 1765, all but four names had disappeared from all sixteen parishes (see Table 4.1). None of the four was still a servant; all were labourers in 1765. Some servants may have been drawn into the militia (which was, after all, the purpose for which the list was made), but the others had disappeared. Three kinds of mobility defeated the attempt to measure any one of them. Servants were mobile over time, in moving frequently; they were mobile over space, in moving some significant distance; and they were mobile socially, in changing their status when entering and eventually leaving service. The temporal and spatial aspects of the movement of servants from master to master are the concern of this chapter.