This is partly covered on Manxnotebook - the Jesuits here from Francis St provided the first continuously resident Catholic priests in the Island since the reformation from the late 18th C. The 1817-1847 reg however sounds the same that is in microfilm (and transcribed by Brian) at the museum - the handwriting is not good however and many names difficult to determine (it appears to me (a guess) to be a rushed copy as required by the 1847 act that retropectively recognised Catholic marriages and Baptisms (along with other non-establishment churches)