After the reinstallment of the papal government, he came into contact with Baldassarre Boncompagni, a Roman prince, mathematician and historian of science, who entrusted him with the care of his library and introduced him to the study of paleography.

[1] In the 1860s, he published in the monthly review Il Buonarroti the Discorso del modo di formare un catalogo universale delle biblioteche d'Italia.

[1] In 1867, Narducci published the work "Giunte all'opera Gli scrittori d'Italia" (letters A and B l) by Count Giammaria Mazzucchelli.

To prove its possibility he compiled an article on Boccaccio, and showed at one view all the editions of that writer and the place where they are to be found.

In 1859 he published the editio princeps of the treatise of Restoro d'Arezzo La composizione del mondo colle sue cascioni.