---
title: "Science in the Enlightenment"
chunk: 7/7
source: "https://en.wikipedia.org/wiki/Science_in_the_Enlightenment"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:12:44.987341+00:00"
instance: "kb-cron"
---

The chemical revolution was a period in the 18th century marked by significant advancements in the theory and practice of chemistry. Despite the maturity of most of the sciences during the scientific revolution, by the mid-18th century chemistry had yet to outline a systematic framework or theoretical doctrine. Elements of alchemy still permeated the study of chemistry, and the belief that the natural world was composed of the classical elements of earth, water, air and fire remained prevalent. The key achievement of the chemical revolution has traditionally been viewed as the abandonment of phlogiston theory in favour of Antoine Lavoisier's oxygen theory of combustion; however, more recent studies attribute a wider range of factors as contributing forces behind the chemical revolution.
Developed under Johann Joachim Becher and Georg Ernst Stahl, phlogiston theory was an attempt to account for products of combustion. According to the theory, a substance called phlogiston was released from flammable materials through burning. The resulting product was termed calx, which was considered a 'dephlogisticated' substance in its 'true' form. The first strong evidence against phlogiston theory came from pneumatic chemists in Britain during the later half of the 18th century. Joseph Black, Joseph Priestley and Henry Cavendish all identified different gases that composed air; however, it was not until Antoine Lavoisier discovered in the fall of 1772 that, when burned, sulphur and phosphorus "gain[ed] in weight" that the phlogiston theory began to unravel.
Lavoisier subsequently discovered and named oxygen, described its role in animal respiration and the calcination of metals exposed to air (1774–1778). In 1783, Lavoisier found that water was a compound of oxygen and hydrogen. Lavoisier's years of experimentation formed a body of work that contested phlogiston theory. After reading his "Reflections on Phlogiston" to the Academy in 1785, chemists began dividing into camps based on the old phlogiston theory and the new oxygen theory. A new form of chemical nomenclature, developed by Louis Bernard Guyton de Morveau, with assistance from Lavoisier, classified elements binomially into a genus and a species. For example, burned lead was of the genus oxide and species lead. Transition to and acceptance of Lavoisier's new chemistry varied in pace across Europe. The new chemistry was established in Glasgow and Edinburgh early in the 1790s, but was slow to become established in Germany. Eventually the oxygen-based theory of combustion drowned out the phlogiston theory and in the process created the basis of modern chemistry.

== See also ==
Scientific method
Rationalism

== Notes ==

== References ==