How did pyromancy use fire and smoke to interpret signs?

Pyromancy is a form of divination that interprets signs through the observation of fire and flames. While the term specifically refers to fire-based methods, historical practices often integrated fire with other elements, such as smoke or heat, to facilitate communication with the supernatural.1

In various traditions, fire was viewed as a medium for spiritual contact. For example, in Inca religious practice, practitioners used metal tubes to blow flames to a red heat, after which a diviner would summon spirits to speak through the fire, often described by chroniclers as a form of ventriloquism. Similarly, in Mesopotamian religion, priests practiced a form of inductive divination by observing the movement and patterns of rising smoke from a sacrifice to discern answers to ritual queries.23

Beyond direct observation of flames and smoke, fire was also used to create physical signs. Scapulimancy, a widespread practice in North America and Eurasia, involved interpreting the patterns of cracks that appeared on a shoulder blade when it was heated by fire.3