- John Dalton (1766-1844)
- Born in England.
- He proposed the atomic theory.
- He stated the law of partial pressure of gases.
- George Davis (1850-1907)
- Born in England.
- He is regarded as the father of chemical engineering.
- Sir Humphry Davy (1778-1829)
- Born in England.
- He laid the foundation of electrochemistry.
- He discovered barium, calcium, magnesium, potassium, and sodium.
- He was evidently the first to observe that platinum induced the oxidation of alcohol vapor in air.
- He introduced a chemical approach to agriculture and to the tanning and mineralogy industries.
- Democritus of Abdera (460 BCE – 370 BCE)
- Born in Greece.
- He conceived matter in the form of particles, which he called atoms.
- Jean Baptiste André Dumas (1800-1884)
- Born in France.
- He made various investigations of organic compounds.
- He developed the theory of substitution.
