HPS211 lec4 Jan22nd
We continue into 18 century, so most of the work is deeply influenced by Newton, as his thought
spread over the continent, especially his idea of mass.
1 Chemistry: Science of substance
2 Pneumatic Chemistry
3 Priestley’s Phlogiston Chemistry
4 Lavoisier’s Oxygen Chemistry
1) Science of Substance
Chemistry used to be used in mix with alchemy. Often concerned itself with change in substance.
Aristotle used earth, water, air, fire (e.g .tree is a wood form of earth and water and air)
Chemistry studies change in substance rather than motion >>physics. Alchemy was very secretive as it’s
a highly valued commodity. Used to be very encrypted.
Alchemy = science of transmutation
Chemistry = science of combination (distinguished by Boyle)
Chemistry as taxonomy >> used for classification and distinguishing while physics only cared about the
Elements and Principles
Wasn’t always distinguished. Boyle thought all matter was same on basic level(similar Aristotle)
2) Pneumatic Chemistry>> of air and gas
Took lots of time to understand that air is homogeneous and non reactive.
Stephen Hales was first to show that some reactions give off air.
Very physical approach to chemistry
Was mainly concerned with how much air, rather than composition
Joseph Black “fixed air”
-fixed in solid bodies
-Shared different airs to have different qualities
-fixed in Mg and release at heat (carbon dioxide)
- Created a Balance Scale that was good, lad to a good measurement of ch