The paper describes the author's witnessing of images projected from an eighteenth-century solar microscope made by John Dollond, now at the Deutsches Museum in Munich. Peter Heering facilitated this session as part of his research on the solar microscope. A rectangular mirror, the length of a hand, mounted outside a museum window caught the sunlight and directed it indoors into the microscope's optical tube with its specimen. Astonishing detail was displayed in the resulting image projected onto a screen at human height. Crisply delineated scales patterned the image cast by a historical specimen of a butterfly wing. Observers interacted fluidly with these images in the very dark room. In sharing what we noticed, questioned and conjectured, we contributed to a temporary community. These participant interactions relate to Steven Shapin and Simon Schaffer's notion that, in the seventeenth century, Robert Boyle used witnessing as a ‘collective act’. Here, the ‘collective act’ spanned participation across history. For example, Robert Hooke's 1665 Micrographia inspired Philip and Phylis Morrison's workshop during my college years and their collaboration with the Eames Office on a film depicting travel through ‘powers of ten’, based on Kees Boeke's 1957 picture book. Personal memories were extended and informed by historical experiences, both for Robert Hooke's subsequent interpreters and for Peter Heering's participants.

Thomas Salusbury's Life of Galileo (1664) was the first substantial biography of Galileo Galilei (1564–1642) in any language. All copies but one were destroyed in the Great Fire of London in 1666. The surviving copy was lost in the library of the Earls of Macclesfield at Shirburn Castle in the mid-nineteenth century. With the auction of the library in 2004–7, it temporarily re-emerged. This essay presents a preliminary description of the copy and its contents. It argues that to understand the existence and nature of the book we need to explore the social relations governing the control of information in early modern Europe. It is shown that Salusbury's project was launched in the face of social and political information blockades and in direct competition with other similar ventures. In particular, rumours of the future publication of an official biography by Vincenzo Viviani (1622–1703) and continuing negotiations over the memory and reputation of Galileo in Italy presented insurmountable barriers to the successful completion of his project. Despite these problems Salusbury's biography, produced on the margins of the emerging Royal Society, presents a spirited portrait of Galileo. Moreover, nearly four hundred years after the event, it offers a new and provocative explanation of the famous trial.

Solar microscopes and their techniques attracted particular attention in the second half of the eighteenth century. This paper investigates the grounds for this interest. After a general introduction to the solar microscope, it discusses the use of original instruments to gain access to the visual culture of solar microscopes and the issues raised by these re-enactments. Experiences involved in this process serve as a basis for reassessing the original source materials. Thence emerges a different account of the meaning of the solar microscope in the eighteenth century and possible reasons for its popularity.

Francis Hauksbee (1660–1713) is well known for his double-barrelled air-pump. However, the origin of this pump, and Hauksbee's background, are often described as a mystery. This text seeks to dispel the riddle. It is argued that Hauksbee's competence as an exceptional maker of air-pumps was developed between 1699 and 1703 as a result of his experiences with the construction, manufacturing and sale of cupping-glasses. His cupping utensils embodied a new design, where syringes were used to evacuate the glasses, instead of the traditional way by fire or mouth suction. These syringes, which in fact were small air-pumps, were perfected between 1699 and 1701. A larger syringe, introduced in 1701, served as a transition from the cupping-syringe to his first air-pump for use in natural philosophy. This syringe was described as a ‘combined engine’, which could serve as an air-pump, a condensing engine and a syringe for injecting air, wax or mercury into pathological specimens. Hauksbee's first air-pump was a single-barrelled model introduced in 1702, based on the combined engine. Its various features, such as easy and convenient leak-tightening, exact pressure measurements by an in-built barometer and an air-inlet function for readmission of air into the receiver, are discussed. Finally, it is shown that these activities gave Hauksbee the reputation of being an outstanding instrument-maker, years before the double-barrelled air-pump was in sight.