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Belatedly, I have uploaded the slides from my presentation at the MAA Mathfest last year, on J.D. Forbes and the developent of curve plotting. Here’s the basic idea.

When, in 2012, experimental evidence for the Higgs boson was announced, it came in the form of a curve with a blip, immediately understood by the audience. Yet 190 years earlier, in 1823, the practice of curve plotting was so unusual that S. H. Christie felt it necessary to explain not only the meaning of the curve for magnetic variation that he presented in the Philosophical Transactions but also the process of defining the axes, representing the data as dots, and drawing the curve.

The development of curve plotting as a technique for relating observational data to mathematized theory appears to have been surprisingly difficult. Early promoters, such as Lambert, were not followed, and not until the 1830s did the method start to spread, following the work of Playfair and Quetelet in statistics, and Herschel and Forbes in natural philosophy (Beniger & Robyn 1978; Hankins, 1999; Tilling 1975).

Tilling identifies a step change in the ubiquity of curve plotting among scientists, initiated by J.D. Forbes, Professor of Natural Philosophy at Edinburgh 1833-1859. Beginning in 1834, he used curves both to present and to analyse observational results relating to heat, meteorology, and glacial flow. This was really handy for me, as Forbes later  became Principal of the United College of St Andrews University (effectively Principle of the whole university), and all his archives are here on my doorstep.

Based on an investigation of Forbes’ notebooks, the paper looks in particular at his curve for daily oscillations in atmospheric pressure, to analyse the the influences on his use of curves. I tentatively conclude that:

  • The form of the horary oscillation curve is a response to very particular circumstances of Forbes’ life in 1831-3. In most other work he used  curves as labour saving and calculational tools
  • Transactions of the RSE encapsulates a strongly visual culture in Scottish science in the 1820s-30s
  • The implicit assumption of an analogue space may have been a barrier to the adoption of curve plotting techniques until the 1830s when increasing confidence in instruments and new ways of seeing allowed their acceptance by authors and audiences


Beniger, James R., and Dorothy L. Robyn. ‘Quantitative Graphics in Statistics: A Brief History’. The American Statistician 32, no. 1 (1 February 1978): 1–11. doi:10.2307/2683467.

Hankins, Thomas L. ‘Blood, Dirt, and Nomograms: A Particular History of Graphs’. Isis 90, no. 1 (1 March 1999): 50–80.

Tilling, Laura. ‘Early Experimental Graphs’. The British Journal for the History of Science 8, no. 03 (1975): 193–213. doi:10.1017/S0007087400014229.