English: Drawings of alembics from a Renaissance chemistry book by Andreas Libavius. These were glass and ceramic hoods for vessels used for distillation. The distillation vessel (called the "cucurbit") would be heated by a flame, the liquid inside would boil and the vapor would rise into the alembic, where it would condense by contact with the cool glass walls and run down the spout into a receiving container. Alembics were invented during the Middle Ages for use in alchemy, the protoscientific precursor to chemistry.