Why Swing the Incense Rather Than Just Burning It? Smoke Has to Travel

The vessel is a metal bowl with a pierced lid, hung from three or four chains gathered at a ring, with a fourth chain running to the lid so it can be raised to add material. Burning charcoal sits inside on a bed of ash or sand, and granules of aromatic resin are placed on it, which smoulder rather than flame and give off a thick fragrant smoke. Swinging the vessel draws air through the holes, which keeps the charcoal alight and pushes the smoke outward in visible clouds.

The practice serves several purposes at once:

• •Honouring an object, a place or a person by directing smoke at them
• •Marking a procession as it moves through a building
• •Purification, both symbolic and practically as a fumigant
• •Representing prayer rising, an image used explicitly in scripture
• •Engaging a sense that nothing else in a service reaches
• •Practically, masking other smells in a crowded building

The material burned is a hardened tree resin, chiefly frankincense from trees growing in southern Arabia and the Horn of Africa, frequently blended with myrrh and other aromatics. That trade was enormously valuable in antiquity and supported entire cities along the routes carrying it north, which is why the substance appears as a gift fit for a king. Harvesting involves cutting the bark and collecting the resin that hardens over weeks. Modern supply is threatened by overharvesting and by the difficulty of regenerating the trees, which are slow growing and increasingly stressed.

Burning aromatic material as part of ritual is close to universal and the parallels are worth noting. Hindu and Buddhist practice uses sticks and cones of compressed aromatic material continuously rather than in a swung vessel. Japanese practice developed incense appreciation into a formal art with its own vocabulary, comparable to tea ceremony. Indigenous traditions across the Americas burn bundles of dried plants for purification. Ancient Egyptian and Mesopotamian temple ritual used it heavily, and Roman practice made offering a pinch of it a test of political loyalty, which is how it became a point of conflict for early Christians.

The most spectacular example hangs in the cathedral at Santiago de Compostela and weighs around eighty kilograms when loaded. It is suspended from the ceiling of the crossing on a rope running over a pulley system, and a team of eight men pulls in rhythm to swing it across the transept, reaching speeds around sixty eight kilometres an hour and rising almost to the roof. It is usually said to have been introduced to counter the smell of pilgrims arriving after weeks of walking, which is plausible and not documented. It has broken loose several times in its history.

A pierced metal vessel of burning charcoal on chains is swung to draw air through it and push fragrant smoke outward, honouring what the smoke reaches and representing prayer rising. The resin burned is chiefly frankincense, whose trade supported cities in antiquity and is now threatened. The example at Santiago weighs around eighty kilograms and needs eight men to swing it.