From the Wikipedia page [1]

The Käymäjärvi Inscriptions refers to inscriptions on a stone approximately 52.5 cm high and 105 cm wide, engraved with characters similar to those found in runic alphabets. The Käymäjärvi Inscriptions are located near Lake Käymäjärvi, about 26 km northwest of Pajala in Northern Sweden.

The stone is today so degraded, it is no longer possible to compare it with other scripts such as Orkhon script or the Kharosthi (Hashtnagar Pedestal) script that uses repeated numerals.

The Käymäjärvi Inscriptions were first reported by Olof Rudbeck, Sr. (1630–1702) in the second volume of Atlantica (1689). The local inhabitants, especially the Saami, considered the stone to carry a very important message from their ancestors.

The second author to report the inscriptions is Eric Brunnius (1706–83) of Uppsala University in a discussion about the town of Tornio (De urbe Torna; 1731). Brunnius states that the stone has rune characters and the engraving of a triple crown but which by that time had been degraded and is now absent. The physicist Anders Celsius (1701–44), also an early runologist, concluded that the inscriptions were not of runic character.

Celsius and Pierre Louis Maupertuis (1698–1759) visited the stone around April 11, 1737, during their Earth meridian measurement expedition. Celsius and Maupertuis both sketched the inscriptions in their diaries of the journey. The tale of this travel and stone, at that time considered to be very exotic in nature, was presented in his application to the Académie des Sciences, and may have influenced the Academy's decision to elect him to the academy.