Bolt-Head

## Bolt-Head Bolt-Head

**The bolt-head** is a long-necked glass flask with a rounded or flat bottom, similar to the matras but with an even longer, narrower neck. The bolt-head was used for digestion, distillation, and operations requiring a vessel with minimal surface area at the top to reduce evaporation. The long neck allowed vapors to rise, condense on the cooler neck walls, and return to the body, creating a gentle circulation. The bolt-head could be sealed hermetically for operations requiring complete containment, or left open or loosely stoppered for operations requiring some vapor release.

The bolt-head was particularly useful for operations requiring prolonged gentle heating with minimal loss of volatile components. The narrow neck minimized evaporation while still allowing for some circulation of vapors. Alchemists used bolt-heads for digesting materials to extract their virtues, for gentle distillation, and for operations related to preparing tinctures and quintessences. The vessel's shape made it suitable for operations where the material needed to be kept concentrated in the body while volatile components circulated through the neck.

The bolt-head's long neck gave it a distinctive appearance, and it appears frequently in alchemical illustrations. The vessel's shape could have symbolic significance: the long neck reaching upward might represent the ascent of spirit, while the rounded body represents the earth or the material realm. The bolt-head thus represents both a practical vessel for gentle heating and circulation, and a symbol of the connection between the material and spiritual dimensions of the alchemical work.

---