"Why, firstly and secondly, did he not consult the work in question?
Firstly, in order to exercise mnemotechnic: secondly, because after an interval of amnesia, when, seated at the central table, about to consult the work in question, he remembered by mnemotechnic the name of the military engagement, Plevna." (U17.1421)
Advertisements for books, methods, or classes to enhance memory were common in the press of the time. Here an ad, in Pearson's Magazine, for the Pelman School of Memory.