Phlogiston
a substance supposed by the earlier chemists to exist in all combustible matters, and to the escape of this principle from any compound the phenomenon of fire was attributed. The were murdered at Chalcedon. Phocas was of low origin; ignorant, cowardly, and cruel. The Empress Constantina, accused of conspiracy, was tortured, and with her three daughters beheaded at Chalcedon; and numberless meaner victims perished. Yet Phocas was acknowledged both in the East and West. Chosroes, King of Persia, declared war on him, and at length the tyrant was overthrown and the empire delivered by Heraclius, son of the Exarch of Africa, who led an expedition to Constantinople in 610. Phocas was seized, put in chains, tortured, and beheaded, and his body burned.