BSHM meeting news

s from past meetings Christmas Meeting and AGM Saturday 3rd December Online Sepideh Alassi (Basel) Scientific challenges and encryption of discoveries in the 17th century rational mechanics Proposing mathematical questions as contests was already popular among Renaissance and early-modern mathematicians including Huygens and Leibniz. Commonly, a mathematical question was proposed to be solved, and the challenger explicitly invited a few mathematicians to solve the problem in a given period of time. In this talk, I will first present a few interesting mathematical challenges initiated by Jacob Bernoulli in the 17th century and then will continue with a discussion about the communicated solutions that were encrypted as ciphers, the similarities and differences of these ciphers, and the reasons for encrypting solutions. Christopher Hollings (Oxford) Triangulating ancient Egyptian mathematics When the details of ancient Egyptian mathematics were being reassembled in the late-nineteenth and early-twentieth centuries, scholars were able to draw upon two British Journal for the History of Mathematics, 2023 Vol. 38, No. 1, 58–66, https://doi.org/10.1080/26375451.2023.2180284 © 2023 British Journal for the History of Mathematics distinct types of information within the surviving sources. In the first instance, the growing understanding of ancient Egyptian languages and scripts made it possible for some basic meaning to be extracted from the texts. Reconstruction of the ancient languages was, however, an on-going process, and so wherever readings were uncertain, it was possible, and necessary, to interpret texts in the light of an understanding of how the mathematical content ought (from a modern point of view) to work. For the most part, these two sources of evidence, the philological and the mathematical, complemented each other. In rare instances, however, they appeared to clash. In this talk, I will examine one such instance, that of Problem 51 of the Rhind Mathematical Papyrus, concerning the area of a triangle, in which philological and mathematical evidence seemed to point in different directions. Clare Moriarty (Trinity College, Dublin) Byrne and Berkeley: Geometric Philosophy and Mathematically Eccentric Irishmen Oliver Byrne published his ground-breaking and visually remarkable edition of Euclid’s Elements in 1847. The book is extraordinary: its pages are adorned with generous four-colour diagrams, illustrations and grids, and each proposition begins with an engraved decorative initial. Its aesthetic similarity to various stylistic themes of the Bauhaus and De Stijl movements has been noted, but less attention has been paid to the pedagogical and theoretical insights that shaped Byrne’s illustrative choices. In this paper, I explain the pedagogical and philosophical insights that motivated Byrne’s unique publication and explore a line of influence in philosophical debates of the previous century. A new connection between Byrne and George Berkeley is revealed, with analysis of the philosophical similarities that motivated both thinkers in their mathematical projects. Maria Niklaus and Jörg F. Wagner (Stuttgart) From Bohnenberger’s Machine via Aircraft Course Controls to Inertial Navigation The Machine of Bohnenberger is the first gyro with cardanic suspension. It was invented at the University of Tübingen in 1810 by the Astronomer and Geodesist J.G.F. Bohnenberger, a pendant of C.F. Gauß in southern Germany. This apparatus served originally for illustrating the precession of the Earth rotation and was made especially popular by P.-S. Laplace and F. Arago in Paris. In 1816, F. Arago presented the instrument to J. Playfair, who brought it to Great Britain. It was also F. Arago, who introduced the instrument to the young L. Foucault. As an alternative to his big pendulum, Foucault tried to improve the Machine in order to create a sensor for the full earth rotation rate. He also introduced the name Gyroscope for such instruments. Although Foucault was not successful with this experiment, he initiated big efforts in developing gyroscopes for vehicle guidance and navigation. Following the success of H. Anschütz-Kaempfe and E. Sperry, who built the first usable gyro compasses in the early 20th century, gyro instruments became standard navigation aids for aircraft after the First World war. Focusing on the 1930s and 1940s the black boxing of gyroscopes for use in aviation is examined in the main part of the presentation. This process is closely linkedwith the Volume 38 (2023) 59