Salmonson set his seel
Solomon's seal, or Star of David, consists of two interlocking triangles. The shape is known as a hexagram ("hexengown") in geometry. The symbol appeared on a magical signet ring used by King Solomon to control demons and spirits.
In the diagram of ALP on page 293 the two triangles can easily be moved to form Solomon's Seal.
"As Stuart Gilbert tells us, Solomon's seal illustrates the opening of the Emerald Table of Hermes Trismegistus". (Roland McHugh, The Sigla of Finnegans Wake, p.71)
The Emerald Tablet, also known as Smaragdine Table, Tabula Smaragdina, or The Secret of Hermes, is an ancient text purporting to reveal the secret of the primordial substance and its transmutations. Its claims to be the work of Hermes Trismegistus ("Hermes the Thrice-Great"), a legendary Egyptian sage or god, variously identified with the Egyptian god Thoth and/or the Greek god Hermes. This short and cryptic text was highly regarded by European alchemists as the foundation of their art, in particular of its Hermetic tradition. http://en.wikipedia.org/wiki/Emerald_Tablet
Salmon: Finn MacCool ate the Salmon of Knowledge. "The young Fionn met the poet Finneces, or Finnegas, near the river Boyne and studied under him. Finneces had spent seven years trying to catch the salmon of knowledge, which lived in a pool on the Boyne: whoever ate the salmon would gain all the knowledge in the world. Eventually he caught it, and told the boy to cook it for him. While cooking it Fionn burned his thumb, and instinctively put his thumb in his mouth, swallowing a piece of the salmon's skin. This imbued him with the salmon's wisdom. He then knew how to gain revenge against Goll, and in subsequent stories was able to call on the knowledge of the salmon by sucking his thumb". http://en.wikipedia.org/wiki/Finn_MacCool