The phlogiston Theory EE EARTH (Phlogiston Poor METAL(Phlogiston Rich FIRE (Phlogiston) Chemistry was so underdeveloped at the time lavoisier gained interest in it that it could hardly be called a science. The prevailing view of combustion was the Phlogiston Theory which involved a weightless or nearly weightless substance known as phlogiston Metals and fire were considered to be rich in phlogiston and earth was considered oxygen poor.The Phlogiston Theory Chemistry was so underdeveloped at the time Lavoisier gained interest in it that it could hardly be called a science. The prevailing view of combustion was the Phlogiston Theory which involved a weightless or nearly weightless substance known as phlogiston. Metals and fire were considered to be rich in phlogiston and earth was considered oxygen poor