These two charms, the Crosh Bollan (fig. 1), and Thor’s Hammer (fig. 2), are of great antiquity, and the former is of particular interest in folk-lore, as it is not confined just to the Isle of Man or even to the “adjacent islands.”
This first charm is the upper palate of the wrass (a rock-fish), of which the Manx name is ‘bollan’, and from its triangular shape is called cross, or ‘crosh bollan’. The merit of the Crosh Bollan is to keep the wearer of it from the power of the Little People, and I am told also that one cannot make a mistake when carrying it on one.
During the summer of 1912, Prof. Boyd Dawkins was staying with Prof. Ridgeway, of Cambridge, who was keenly interested in a charm that had just been sent to him from the Aegean Islands and which was still in use there. On seeing the charm, Prof. Boyd Dawkins exclaimed “I can send you a duplicate of that from the Isle of Man!” and gave Prof. Ridgeway a Crosh Bollan precisely similar to the Aegean one. It would seem that certain charms were almost as common a symbol among widely separated peoples, as the ‘Fylfot’.
The Thor’s Hammer is also from the mouth of an animal, being one of the tongue bones of the sheep. Its use is to show the right road to take when in unknown country. Some fifteen years ago I was driving on the Curraghs, and came to cross roads which puzzled our driver. He exclaimed to us, “I wish I had my charm in me pocket an’ then I could tell the way to take.” On being asked about his charm, he explained that you throw it down on the ground and the long arm will point to the right road for you.
(source: from Mannin Vol II (1913))