The conclusion of the preceding three chapters, that the patent rolls have little value as an accurate reflection of the directions of technical change or of the timing and pace of invention, is not a sufficient reason for dismissing them as merely a record of patenting per se. While certainly not inclusive of all inventions and deficient in some areas more than in others, patents do have something to say about inventive activity. The prevalence of certain types of invention is indicative of stresses and opportunities at those points in the economy to which they are addressed, and with caution they can be tentatively interpreted. What should be avoided is the assumption that they represent the total picture. Up to this point I have looked beyond the gross statistics to investigate what types of invention were patented, in which industries and by whom. This information by itself is insufficient to discover the technological problems and possibilities that exercised the brains of inventors. These may be approached, however, by examining the explanation of the invention which the patentee himself gives. By this means something may also be discovered about more general, underlying assumptions concerning the economic functions of technology in England at this period and changes in those assumptions over time. Which was more important: saving labour or saving capital? Did the notorious leisure-preference of the workforce inspire technical innovation, or was the burden of unemployment on the parish rates a weightier consideration? Were there chronic shortages which demanded a shift in the resource base?