In the Ruy Lopez Yale has retaken the exchanged pawn, and Harvard's rook has taken possession of the important king's file.
(12) K Kt takes P. (12) R to K square.
In the Scotch opening, Harvard does not yet dare to take the proffered rook, but is evidently bent on forcing an exchange of queens. Harvard's twelfth move was Q - KB 2, not Q - KB 3 as published:
(13) Q to B 4 (12) Q to R 3.