Topic 4 - Why did the study of electricity increasingly become an integral part of natural philosophy during the eighteenth century? How did this reflect important shifts in the intellectual culture of the Enlightenment?
Background: This subject covers the history of science, starting with early natural philosophers (Aristotle, Plato), through to the Renaissance and early modern period, focusing on works by Kepler, Galileo, Descartes and Newton. Over the course of the semester, we covered topics like medieval and renaissance alchemy, the rise of the mechanical philosophy, and different attempts throughout history to understand the nature of matter and force
Essay instructions: 2000 words, footnotes and bibliography (Chicago style, but not strictly). Don’t use in-text citation. Each footnote should include as a minimum, the author, title, year of publication and a page number where necessary.
Additional instructions from lecturer: Depth of information over breadth. If there are too many things to cover, focus on particular issues and mention the others briefly in introduction (don’t leave out stuff, but don’t go into detail about everything). Not a history of the present – don’t discuss how it is relevant to today. Divide into sub-sections. Use both primary AND secondary sources (e.g. Du Fay and Aepinus are primary sources, while Schiffer is not. Refer to history referencing guides).
People to mention: Du Fay, Aepinus, Faraday, Benjamin Franklin, Nollet, Newton (query 31).
Basic structure (not something to follow strictly!):
- Intro – discuss context, background – relevant scientific progress that led up to the work on electricity. Introduce concepts that will be discussed, argument – something along the lines of: The study of electricity expanded the limitations of natural philosophy to encompass a range of new sciences, which would be important for the move to quantitative science, scientific measurement, evolution of modern science, etc.
- 1 – Early developments (1730s-40s) Du Fay’s theory of vitreous/resinous electricity varieties, invention of the Leyden jar.
- 2 – Franklin’s fluid theory (1740s-50s) (positively/negatively charged),
- 3 – Nollet’s theory of vitreous/resinous types of electricity, Aepinus’s work.
- 4 – Newton’s query 31 and its relevance, Faraday’s future significance.
- Conclusion – Summary. Discuss Enlightenment and conclude with what came after.
Relevant lecture notes:
- 18th century, culture of enlightenment; natural philosophy was growing to encompass sciences, before it looked down on them because they couldn’t explain the cause of things.
- Republic of letters also emerged. Created an international network where exchanges of discoveries could be discussed. The Salon also opened, became a cultural hub. Public lectures and demonstrations (experimental) were being held (The electric kiss, the flying boy, etc).
- The phenomena of electricity – emerged as a craze. An enigmatic and rare phenomenon early on. Lightening not considered electricity then. Most requested form of polite entertainment. Became a spectacle. Associated with romanticism (‘sparks’ flying).
- Electricity: not readily found in nature. Needed to be generated to be studied (not easy – disappeared as quickly as it was produced, quickly discharged – no electric current or batteries yet) – hence, it’s an artificial phenomenon.
- Earliest electrical experiment – friction to get sparks. Frictional electrostatic generator development. Natural philosophers beginning to show interest in the phenomenon.
- To understand it, they needed better methods of generating electricity.
- DU FAY: 1730s, electricity was virtually not even a science yet. Such a difficult to tame phenomenon. He established that electricity can act as a repulsive force (as well as attractive – which is odd). This ability is perplexing. Variability of electricity – temperamental.
- Du Fay carried out exploratory experiments, not testing a hypothesis or searching for the cause of electricity. Wanted to know which materials were easily electrified, etc.
- ‘If-then’ experiments, aim was to find an empirical regularity. Had to change fundamental language – assumed there were 2 kinds of electricity: Resinous (amber) and vitreous (glass). Each repelled itself and attracted the other. No conclusions drawn about what electricity is.
- Humans attract electricity – experiments must take this into consideration.
- Nollet experiment – the Leyden jar to store electricity in 1751, electric shock through soldiers. First battery. Storing electric charge – developed by von Kleist and Muschenbroek. Touching the inside/outside of jar with hands provoked instantaneous electric discharge to the body.
- Dominant theory of electricity – 2nd half of 18th century. Query 31 from Newton’s ‘Optics’ – electrical attraction operating at the microscopic level and without friction.
- SUBTLE FLUIDS – new speculative theories emerging. 1740-50s – qualitative/non-mathematical, due to difficulty with precision. Hypothesis of Benjamin Franklin – invisible subtle fluids, tiny particles of fluid between particles of ordinary matter. Soaks into ordinary bodies. Imponderable/weightless. Exert attractive/repulsive forces of insensible (tiny) distances.
- Franklin – all bodies have some electric fluid. Particles of electric fluid repel one another. Therefore, it jumps sporadically. Attracted to ordinary matter.
- Positive and negative electrification – positive is a surplus of electrical fluid, negative is a deficit. This is an application of Newton’s Query 31. Fluid metaphors, not yet electric current.
- Tiny particles of matter, attractive and repulsive forces. Attract ordinary matter. Some objects more attractive force. Early chemistry of 18th century.
- New style of speculative natural philosophy in 1740s-60s. Explanation of phenomena regarding subtle fluids. There were also magnetic fluids.
- Increasing acceptance of attractive and repulsive forces, in middle 18th century (unknown cause, like Newton - agnostic). Theories are still speculative, not quantitative.
- Microscopic theories. Cannot assign numbers yet – measurement is difficult without regularity.
- Remained qualitative for good part of 18th century. No mathematical laws until later.
- Poisson and Aepinus – theories of electricity and magnetism. Early 19th century – belief in 2 fluids, positive and negative, as well as electric and magnetic.
- Afterwards – natural philosophy began splitting off into different science categories. New measurement techniques.
- Scientific culture of the enlightenment – second half of 18th century – shift towards precision measurement and quantitative. Difficult to use experimental instruments without a way to measure the effects (requires standardization).