Brewer's: Hermetic Powder
The sympathetic powder, supposed to possess a healing influence from a distance. The mediæval philosophers were very fond of calling books, drugs, etc., connected with alchemy and astrology by the term hermetic, out of compliment to Hermes Trismegistus. (
For by his side a pouch he wore Replete with strange hermetic powder, That wounds nine miles point-blank would solder.