From The Long Lost Friend:
Before sunrise on St. Bartholomew's Day, you must dig up four or five roots of the dandelion weed, taking good care to get the ends of the roots; then you must procure a rag and a thread that have never been in the water; the thread, which dare not have a single knot in it, is used in sewing up the roots into the rag, and the whole is then to be hung before the eye until the scum disappears. The tape by which it is fastened must never have been in the water.
The grimoire The Long Lost Friend lists this spell.
Timeline of related events
1820Publication of Hohmann's Long Lost Friend (lists this spell)