On 26 February 1616 Galileo was ordered to cease to defend heliocentrism in any way whatsoever. This order, called a precept, automatically applied to anything he might later attempt to publish on the subject. Issued at the end of his first trial by the Roman Inquisition, the precept became the spark that triggered his second trial in 1632–3 and figured importantly in the justification of his sentence. This precept has been a subject of controversy since the late nineteenth century for its authenticity, legality and legitimacy. This paper addresses the first two points and establishes the facts of what probably happened in 1616. It does so by examining seven texts that bear on the event. All but one of these (plus Galileo's first deposition in 1633) agree tolerably well that Galileo did indeed receive the precept in the strongest form. An examination of the singleton text in the context of how the Inquisition produced and kept its records as well as of its procedures and personnel shows that it is the least reliable source. This context also supports the argument that certainty about what happened is impossible to achieve. The theory that the document most damaging to Galileo was a forgery is also disposed of. Examination of the crucial phrase successive ac incontinenti in one of the documents supports the paper's suggestion that more caution is in order before accepting the currently nearly universal claim that the precept was improper in law.

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.

Even during its heyday, American behaviourist psychology was repeatedly criticized for the lack of diversity in its experimental subjects, with its almost exclusive focus on rats and pigeons. This paper revisits this debate by examining the rise and fall of a once promising alternative laboratory animal and model of intelligence, the raccoon. During the first two decades of the twentieth century, psychological investigations of the raccoon existed on the borderlands between laboratory experimentation, natural history and pet-keeping. Moreover, its chief advocate, Lawrence W. Cole, inhabited the institutional and geographic borderlands of the discipline. This liminality ultimately worked against the raccoon's selection as a standardized model during the behaviourist era. The question of raccoon intelligence was also a prominent topic in the contemporaneous debates over the place of sentiment in popular nature writing. Although Cole and others argued that the raccoon provided unique opportunities to study mental attributes such as curiosity and attention, others accused the animal's advocates of sentimentalism, anthropomorphism and nature faking. The paper examines the making and unmaking of this hybrid scientific culture as the lives of experimenters and animals became entangled.

This paper follows the history of an object. The purpose of doing so is to come to terms with a distinctive kind of research object – which we are calling a ‘test object’ – as well as to chronicle a significant line of research and technology development associated with the broader nanoscience/nanotechnology movement. A test object is one of a family of epistemic things that makes up the material culture of laboratory science. Depending upon the case, it can have variable shadings of practical, mathematical and epistemic significance. Clear cases of test objects have highly regular and reproducible visible properties that can be used for testing instruments and training novices. The test object featured in this paper is the silicon (111) 7×7, a particular surface configuration (or, as it is often called, a ‘reconstruction’) of silicon atoms. Research on this object over a period of several decades has been closely bound up with the development of novel instruments for visualizing atomic structures. Despite having little direct commercial value, the Si(111) 7×7 also has been a focal object for the formation of a research community bridging industry and academia. It exhibits a complex structure that became a sustained focus of observation and modelling. Our study follows shifts in the epistemic status of the Si(111) 7×7, and uses it to re-examine familiar conceptions of representation and observation in the history, philosophy and social study of science.