In 1948, in response to the perceived threat of atomic war, the British government embarked on a new civil defence programme. By the mid-1950s, secret government reports were already warning that this programme would be completely inadequate to deal with a nuclear attack. The government responded to these warnings by cutting civil defence spending, while issuing apparently absurd pamphlets advising the public on how they could protect themselves from nuclear attack. Historians have thus far sought to explain this response with reference to high-level decisions taken by policymakers, and have tended to dismiss civil defence advice as mere propaganda. This paper challenges this interpretation by considering the little-known role of the Home Office Scientific Advisers' Branch, a group of experts whose scientific and technical knowledge informed both civil defence policy and advice to the public. It explores both their advisory and research work, demonstrating their role in shaping civil defence policy and showing that detailed research programmes lay behind the much-mocked government civil defence pamphlets of the 1950s and 1960s.

In La nova scientia (1537), Niccolò Tartaglia analyses trajectories of cannonballs by means of different forms of reasoning, including ‘physical and geometrical reasoning’, ‘demonstrative geometrical reasoning’, ‘Archimedean reasoning’, and ‘algebraic reasoning’. I consider what he understood by each of these methods and how he used them to render the quick succession of a projectile's positions into a single entity that he could explore and explain. I argue that our understanding of his methods and style is greatly enriched by considering the abacus tradition in which he worked. As a maestro d'abaco in sixteenth-century Venice he had access to a great variety of mathematical and natural-philosophical works. This paper traces how Tartaglia drew elements from a vast spectrum of sources and combined them in an innovative manner. I examine his use of algebra and geometry, consider what he knew about Archimedes and suggest a reading of his enigmatic phrase ‘Archimedean reasoning’, which has eluded satisfactory interpretation.

This article places the famous images of Johannes Hevelius's instruments in his Machina Coelestis (1673) in the context of Hevelius's contested cometary observations and his debate with Hooke over telescopic sights. Seen thus, the images promote a crafted vision of Hevelius's astronomical practice and skills, constituting a careful self-presentation to his distant professional network and a claim as to which instrumental techniques guarantee accurate observations. Reviewing the reception of the images, the article explores how visual rhetoric may be invoked and challenged in the context of controversy, and suggests renewed analytical attention to the role of laboratory imagery in instrumental cultures in the history of science.

In 1927, George Paget Thomson, professor at the University of Aberdeen, obtained photographs that he interpreted as evidence for electron diffraction. These photographs were in total agreement with de Broglie's principle of wave–particle duality, a basic tenet of the new quantum wave mechanics. His experiments were an initially unforeseen spin-off from a project he had started in Cambridge with his father, Joseph John Thomson, on the study of positive rays. This paper addresses the scientific relationship between the Thomsons, father and son, as well as the influence that the institutional milieu of Cambridge had on the early work of the latter. Both Thomsons were trained in the pedagogical tradition of classical physics in the Cambridge Mathematical Tripos, and this certainly influenced their understanding of quantum physics and early quantum mechanics. In this paper, I analyse the responses of both father and son to the photographs of electron diffraction: a confirmation of the existence of the ether in the former, and a partial embrace of some ideas of the new quantum mechanics in the latter.