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.

Early Victorian analogical arguments were used to order the natural and the social world by maintaining a coherent collective experience across cultural oppositions such as the ideal and material, the sacred and profane, theory and fact. Maxwell's use of analogical argument in ‘On Faraday's lines of force’ was a contribution to that broad nineteenth-century discussion which overlapped theology and natural philosophy. I argue here that Maxwell understood his theoretical work as both a technical and a socially meaningful practice and that embedding his use of analogy in the social and intellectual context of Victorian Britain provides a means of telling a sociocultural history of Maxwell's development of a new cognitive tool: a way of thinking on paper analogous to thinking with objects in the laboratory.

This paper examines the interrelations between astronomical images of nebulae and their observation. In particular, using the case of the ‘Great Spiral’ (M51), we follow this nebula beginning with its discovery and first sketch made by the third Earl of Rosse in 1845, to giving an account, using archival sources, of exactly how other images of the same object were produced over the years and stabilized within the record books of the Rosse project. It will be found that a particular ‘procedure’ was employed using ‘working images’ that interacted with descriptions, other images and the telescopic object itself. This stabilized not only some set of standard images of the object, but also a very potent conception of spirality as well, i.e. as a ‘normal form’. Finally, two cases will be contrasted, one being George Bond's application of this spiral conception to the nebula in Orion, and the other Wilhelm Tempel's rejection of the spiral form in M51.

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.