Thomas Harriot’s use of medieval diagrams of change in his notes on the motion of fall, motion along inclined planes, and projectile motion. On this particular folio Harriot determines the ratio of the velocities of two downwards motions, one along a vertical line of given length and one along an inclined plane of the same length (British Library Add MS 6789, f. 31r, excerpt)
Project (2000-2012)

The Use of Scholastic Tools in Early Modern Mechanics

The mathematical tools that were further developed or originated in the medieval scholastic tradition, such as the theory of proportions or the diagrammatic representation of change usually associated with the name of Nicolàs Oresme, constituted an important precondition for the mathematical treatment of various subjects of early modern science. In the case of early modern treatments of the motion of fall, the combined application of these two tools resulted in new interpretations of the diagrams themselves and eventually in the transformation of fundamental mechanical concepts like that of velocity. The hitherto unpublished working notes of the English mathematician and philosopher Thomas Harriot (1560–1621) contain the most systematic exploration of the implications of the medieval diagrams for the understanding of motion known to us. They clearly reveal the new practical contexts of early modern applications of medieval tools, such as the increasing importance of artillery in early modern warfare, as well as the conceptual difficulties that had to be overcome, such as the interpretation of diagrams in terms of proportions relating space traversed, time elapsed, and velocity. A comprehensive edition and detailed analysis of Harriot’s manuscripts on motion has been published as a two-volume set in the Department’s series on The Historical Epistemology of Mechanics: The English Galileo: Thomas Harriot’s Work on Motion as an Example of Preclassical Mechanics. The book contains facsimile reproductions and transcriptions of the 180 folio pages as well as a thorough interpretation that sets Harriot’s work in the context of early modern mechanics.


Schemmel, M. (2006). The English Galileo: Thomas Harriot and the force of shared knowledge in early modern mechanics. Physics in Perspective,8(4), 360-380.

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Schemmel, M. (2012). Medieval representations of change and their early modern application. Foundations of Science online, 1-24.

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