Paper, 'Observations on last weeke's experiment to demonstrate the phlogiston or aether in mars and oil of vitriol by explosion, and how to condense it' by unknown author Paper describing various experiments that demonstrate the phlogiston, a theorised fire-like element released during combustion, using oil of vitriol [sulphuric acid] and mars, a pigment made from an iron oxide base. The author also provides remarks on these experiments and on similar experiments relating to the phlogiston carried out by Sir Isaac Newton. Subject: Chemistry Read to the Royal Society on 15 February 1729 [1730]. 1 February 1730