One held that bitumen was inorganic and bore no relation to living things, whereas the other theorized that it somehow formed from once-living plants or animals. The ancient Greek philosopher Aristotle taught that everything we touch or feel is made up of the base elements of earth, air, fire and water. These elements are never found in a pure state and consist of a mysterious matrix infused with the properties of warm and dry, or the opposing properties of cold and wet. Earth was dry and cold, air wet and hot, fire dry and hot, and water wet and cold. Aristotle believed that stones, ores and fossils form as deposits from exhalations deep within the earth that are trapped in pores and fissures.
Wet exhalations produce metals, dry ones produce stones.
Aristotle's followers suggested that the foul smell associated with most bitumen indicated that it was a form of liquid sulfur, a compound they attributed to dry exhalations. Two theories on the origin of petroleum developed during the Renaissance. The more popular was proposed by Agricola, a German physician who agreed with Aristotle and wrote in 1546, in a textbook on mining and minerals, that bitumen formed from exhalations of sulfur deep within the earth. By contrast, Libavius, another German physician, theorized in 1599, in a chemistry textbook, that bitumen might form from the resins of ancient trees. Leo Lesqueroux, the father of paleobotany, decided in 1866 that petroleum in Pennsylvania formed from marine algae in Devonian shales much the same way that coal forms from land plants.