I was thinking it might be to indicate the etymology of the word from some language, but I don't know how likely that is and the rules say I need more characters.
It's probably a case of move along nothing to see here, or some stylistic effect to make it look latin, as suggested by Pieter in his comment.
I and J used to be used interchangeably. It's only during the Renaissance (Gian Giorgio Trissino in 1524) that the idea of using the two letters to represent different sounds emerged. The first English book to make the distinction between the two was "English Grammar" by Charles Butler in 1633 (1634? sources don't seem to agree). On top of this, spelling wasn't entirely normalized at the time.