A sign for retort,
distillery tube. It also sometimes was used to symbolize the process of
A retort or alembic is a glass vessel with a long, tapering, down-angled neck or beak, used for heating up liquids and letting the gas out via the beak into a cooled flask for condensation. Retort was also drawn and in alchemy.
The process of distillation could be drawn , the ideogram for the zodiac sign of Virgo.
See the two sections on alchemy in the Appendices for data about the distillation process in the alchemists' program.