The straight line balance spring regulator It is generally the case that in the extensive literature recording the history of English Horology, the invention of the "straight line" or "endless-screw" regulator has been attributed to Nathaniel Barrow (Apprentice 1653, Clockmaker's Company 1660, Master 1669). In France, the same invention has been attributed to Jacques Gloria, whose working dates are comparable. Although the latter was virtually alone in France to employ the idea, there were perhaps a handful of English makers who used it, albeit rarely. It may be that Barrow's claim is based more on subsequent writings than on historical fact. A slightly earlier system employed by Henry Jones, used a completely straight spring mounted on the cock and acting between two pins on the balance, which could have inspired the idea. Thomas Tompion's curved rack-and-pin regulator, held under a separate cock, was probably introduced before 1680, and there is no reason to believe that the watch now offered for sale is much later. However, as with any new invention, Tompion would undoubtedly have been circumspect about allowing his peers to copy the idea at its inception. Nevertheless, rumours of the advance must have been rife, and other makers would have striven hard to emulate the idea. The "Barrow" system is in fact a combination of the old and the new in its layout; the worm screw occupying the position of the pre-balance spring wormand- wheel set-up brackets, but with the addition of the newly invented spring. It may well be that the system was in fact an interpretation of Tompion's idea, arrived at without the benefit of seeing an example of the master's work. Certainly examples are exceptionally rare, and the idea was very quickly dropped.