This well-known story tells how Finn McCool obtained the gift of Knowledge. It comes to us through a 15th century transcription of an older, lost manuscript (c. 900), the Saltair of Cashel. David Comyn's edition of this text was first published by the Gaelic Union in 1881, and his was based on an edition by John O'Donovan published by the Ossianic Society in 1859. Both of these societies published bilingual books, with Irish-language text and facing translation.

Scéal clúiteach é seo faoin slí ina fuair Fionn Mac Cumhaill buadh an fheasa. Tá sé le fáil i cóip a deineadh sa 15ú céad de lámhscríbheann atá caillte anois, Saltrach Chaisil, a chuireadh le chéile timpeall 900. Foilsíodh eagrán Dháithí Coimín ag Aondacht na Gaeilge i 1881. Bhí an t-eagrán sin bunaithe ar eagrán le Seán Ó Donnabháin a d'fhoilsigh an Ossianic Society i 1859. D'fhoilsigh an dá chumann seo leabhair dátheangacha leis an téacs agus an t-aistriúchán ar aghaidh a chéile amach.

Seven years had been spent by Finneigeas by the Boyne, watching for the salmon of the pool of Feic; for it was prophecied that if he ate the salmon of Feic nothing would be unknown to him afterwards.

The salmon was caught and it was left to Deimne [= Fionn's earlier name] to cook it, and the poet told him not to eat any of it. The youth brough him the salmon when it had been cooked.

"Did you eat any portion of the salmon, O youth?" asks the poet. "No" - says the youth; "but I burned my thumb, and then I put it in my mouth." "What is your name, O youth?" he says. "Deimne", says the youth. "Fionn [= fair, wise] is your name," says he, "O youth, and it is you who were destined to eat the salmon, and it is you who are the Fionn truly."

The youth then eats the salmon. That is, by-the-way, how Fionn gained knowledge, whenever he used to put his thumb in his mouth....

Secht mbliadhna do Finnécis for Bóinn oc urnaige iach Linne Feic; air do buí a tairrngire do eo Feic do tomailt, ocus cen ní na ainfis itir iarum.

Frith in m-bradan, ocus ro h-erbad do Deimne umorro in bradan do fuine, ocus asbert an file fris cen ní don bradan do tomailt. Do bert in gilla do an bradán iar na fuine.

In ar tomlis ní don bradan, a gilla, ol in file. Níto, ol in gilla, acht mo órdu do loisces, ocus do radus im beolu iartain. Cia h-ainm fil ort-sa, a gilla, ol se. Deimne, ol in gilla. Find do ainm, ol sé, a gilla, ocus is duit tucad in bradan dia tomailt, ocus is tu in Find co fír.

Toimlid in gilla in bradan iartain. Is sin tra do rat in fis do Finn .i. an tan do bered a ordain i n-a beolu....