During the mid-18th century, when electricity was coming into its own, natural philosophers began to entertain the possibility that electricity is the mysterious nerve force. Their attention was first drawn to several species of strongly electric fish, namely torpedoes, a type of African catfish, and a South American "eels." This was because their effects felt like those of discharging Leyden jars and could be transmitted along known conductors of electricity. Moreover, their actions could not be adequately explained by popular mechanical (...) theories. Many of the early documents supportive of the hypothesis of animal electricity were associated with the Dutch colonies in South America. This article presents and examines those documents, and shows how Dutch scientists on both sides of the Atlantic conducted experiments and communicated with each other in the 1750s and 1760s. It reveals the important roles played by inquisitive physicians and lovers of nature in South America, and by natural philosophers and collectors of exotic specimens in the Netherlands—learned men who began to make a credible case for animal electricity in some exciting places at a pivotal moment in time. (shrink)

During the mid-18th century, when electricity was coming into its own, natural philosophers began to entertain the possibility that electricity is the mysterious nerve force. Their attention was first drawn to several species of strongly electric fish, namely torpedoes, a type of African catfish, and a South American "eels." This was because their effects felt like those of discharging Leyden jars and could be transmitted along known conductors of electricity. Moreover, their actions could not be adequately explained by popular mechanical (...) theories. Many of the early documents supportive of the hypothesis of animal electricity were associated with the Dutch colonies in South America. This article presents and examines those documents, and shows how Dutch scientists on both sides of the Atlantic conducted experiments and communicated with each other in the 1750s and 1760s. It reveals the important roles played by inquisitive physicians and lovers of nature in South America, and by natural philosophers and collectors of exotic specimens in the Netherlands—learned men who began to make a credible case for animal electricity in some exciting places at a pivotal moment in time. (shrink)

The eighteenth century was an era in which science came to play a major role in the cultural ideal of the city elite. The phenomenon of the ‘gentleman-scientist’ arose: a layman without a scientific education who for a variety of often socially desirable reasons devoted himself to scientific endeavours. Scientific instruments were the tools for this interest. This article describes the introduction, diffusion, and construction in the Netherlands of one of the most prominent eighteenth-century instruments: the reflecting telescope. The reception (...) of this instrument casts new light on the usually almost invisible network of gentleman-scientists and instrument-makers in this region. The specific economic and political factors of the Netherlands led to a totally different development of this instrument compared with the ‘motherland’ England. Whereas in Great Britain the reflecting telescope was a great success well into the nineteenth century, in the Netherlands it became a symbol of technical inability and stagnation. (shrink)

The focus of this paper is one of James Prescott Joule’s scientific contributions: the laws of heat production by electric currents in conductors. In 1841, the 22 years old Joule published a paper with the title “On the heat evolved by metallic conductors of electricity, and in the cells of a battery during electrolysis” where he presented an experimental study of that phenomenon and proposed two laws that were allegedly supported by his trials. On closer inspection, both his laboratory work (...) and his inferences can be challenged. The emphasis of this article is an attempt to understand Joule’s experimental undertaking, its highpoints and shortcomings, by a detailed analysis of this specific episode and by studying the precedents of his work and subsequent advancements. It is possible to point out several serious deficiencies of that investigation, and Joule’s contemporaries, such as Edmond Becquerel and Heinrich Lenz, did criticize some of his flaws and undertook new experiments to provide a sound basis for those laws. Besides providing a historical examination of that specific episode, this article uses this case study to tackle some features of the nature of science that may contribute to scientific education. (shrink)