By analysing the historical case of the proportionality between inertia and gravitation, it is possible to reconstruct one of the most relevant moments in the history of physics, that is to say, the one linked with Eötvös' experiments. At the same time, this reconstruction offers the opportunity to carry out philosophical considerations about the relationship between theory and experiment and about the concept of incommensurability.

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. (shrink)