A ring or some other accoutrement, probably symbolizing a frog, was during rituals moved around on the drum membrane, which contained some hundreds of runes (elks, sun, thunder, etc.). From its spontaneous selection of a given rune, predictions and conclusions were made from the matched rune itself and the path that the ring would take in selecting it.[this quote needs a citation]
Only about 70 drums have been preserved until today, and most of those date back only to the 17th or 18th century. Probably the best-known is the Linné drum – a drum that was given to Carolus Linnaeus during his visits in the northern Sweden. He later gave it to a museum in France, and recently it was brought back to the Swedish National Museum.