When did human beings discover oxygen?
In trying to figure out fire, human beings discovered something even more fundamental: oxygen. They found out that if the oxygen level was low enough, a fire could not exist, and may even be suppressed by lowering the oxygen in a fire zone. Artist and inventor Leonardo da Vinci was among the first to note that a flame goes out without air, like a living being suffocates. The oxygen was identified as the “living source” necessary to humans and also to combustion processes.
