Chasing the line: Hutton’s contribution to the invention of contours

This article describes one aspect of the history, invention and use of contour lines. We present a case that Charles Hutton – working for the Greenwich Royal Observatory – might have created one of the first accurate and useful contour maps, based on a survey of Schiehallion in Perthshire, Scotland. Hutton’s description of this map and his calculations (used to determine the density of the Earth) were published by the Royal Society in 1778. The map is missing; however, this paper provides all the information, based on the surveyors’ measurements, to create a fairly accurate contour map of Schiehallion. Our collaboration, between mathematician and artist, led to a visual reinterpretation of the data based on the original calculations in Hutton’s paper, and his other maps. In this article, we document our re-creation of the map of Schiehallion and subsequent and corresponding three-dimensional contour models of the mountain.