Abstract

The maker of a regularly divided scale is faced with a task of such conceptual simplicity that he is bound to fail, such is the nature of real materials and men. Using sophisticated modern measuring tools, we can now accurately chart the error in every division of an old linear scale. The resulting pattern of errors across the scale provides a unique signature, containing a random component that could not be precisely repeated by the artisan, and a systematic component, reflecting the fine detail of the technique he used. Taking a small sample of scales made for different purposes about 200 years ago, from a precision linear measure by J. Sisson to two mountain barometer scales by J. Miller of Edinburgh, a method of examining the error pattern is discussed using statistical techniques developed for time series analysis. From the quantitative information present in the division sizes and their errors, useful conclusions and inferences are drawn on the origin of the scales, the tools and the techniques used by individual makers