Instruments and experiments. The case of atmospheric electricity in eighteenth-century Holland In this paper we examine the intricate relationship that exists between theory, scientific observations and laboratory experiments, using atmospheric electricity in eighteenth century Holland as a case study. The three techniques applied to studying electrical processes in the atmosphere, and which also resulted in developing new instruments, were observing and measuring the phenomena in nature, recreating and analysing the same phenomena in the laboratory, and making scale-model experiments when direct intervention with the natural processes was not possible. In the course of this analysis we observe some of the strength and weaknesses of the eighteenth-century experimental method, and also the two-way interactions between advances in instrumentation scientific exploration and discovery.