and quantity. Moreover, it could be dangerous and volatile. Since the smoke point of oil is lower than its boiling point, the oil was only heated and not boiled. Pouring-oil was used in historic battles, and Josephus described its use at Jotapata in AD 67, saying "the oil did easily run down the whole body from head to foot, under their entire armour, and fed upon their flesh like flame itself." Oil was usually used to create incendiary devices. The Roman-Byzantine armies of the 6th century created "fire-pots", oil-based incendiary weapons which could be launched by hand or with ballistae. During the siege at Montreuil-en-Bellay in 1147, a mixture of oils from nuts, cannabis and flax, was heated in iron containers, launched by mangonel, and burst into flames on impact. The Chinese made early grenades out of oil-soaked hemp and cotton, which were ignited and thrown by mangonels. Another use of oil can be seen in the naval battle of La Rochelle during the Hundred Years' War; the Castilians sprayed oil on the decks of English ships then ignited it by shooting flaming arrows down. Water, sand and other heated missiles Hot oil was considerably less common than boiling water or heated sand, which were cheap and extremely effective; even "dust from the street" could be used. These would penetrate armour and cause terrible burns. Sand, especially, could work its way through very small gaps in armour. The Phoenicians at the Siege of Tyre (332 BC) dropped burning sand down on the attacking Greeks, which got in behind the armour and burned the flesh. Such heated missiles have also been used in mining situations; the 1st century Roman writer Vitruvius describes a counter-mine dug above the attackers' gallery by defenders at the siege of Apollonia. Piercing the floor between the mines, the Apollonian defenders poured down boiling water, hot sand and hot pitch onto the heads of their enemy. Other mixtures were more innovative; the defenders at Chester in 918 boiled a mixture of water and ale in copper tubs and poured it over the Viking besiegers, causing their skin to peel off. When Frederick I Babarossa besieged Crema, Italy in the 12th century, the defenders threw red-hot iron objects down on their attackers. Pitch, tar and resin Burning pitch was used on occasion. The Sasanians threw fire pots containing sulfur, pitch, and naptha ("oil of Medea") against Roman siege