A treatise on the nature and properties of fire. Theophrastus examines how fire differs from the other elements, why it needs fuel to sustain itself, and the various forms that combustion takes in nature and human use.
Start ReadingFire as an element. Theophrastus examines how fire differs from earth, water, and air in its nature and behaviour.
The fuel requirement of fire. Theophrastus investigates why fire alone among the elements cannot sustain itself without an external source of nourishment.
How fire is produced — friction, compression, concentration of sunlight, and the striking of flint.
The heat of the sun and its relationship to terrestrial fire. Theophrastus examines whether solar heat operates by the same principles as ordinary combustion.
Fire in living organisms. Theophrastus examines the role of innate heat in animals and plants, and how it differs from external fire.
The different forms of combustion — steady flame, smouldering, charcoal burning — and the conditions that produce each.
Extinction and resistance to fire. Theophrastus examines what makes some materials fireproof and how fire can be extinguished.
The transformative effects of fire on materials — smelting, firing pottery, cooking, charring — and why different substances respond differently to heat.
Spontaneous combustion and underground fires. Theophrastus investigates cases where fire appears to arise without an obvious ignition source.
Fire in metalworking and the arts. Theophrastus examines the controlled use of fire in smelting, forging, and glass-making.
The colour and brightness of flames. Theophrastus investigates why different fuels produce flames of different colours.
Smoke, ash, and the products of combustion. Theophrastus examines what fire leaves behind and why.
Concluding observations on the unique nature of fire among the elements and its indispensable role in human life.