He also worked on the history of his home town, and published his researches in eight volumes: "Il lago maggiore Stresa e le isole Borromeo" (Prato, 1875–78); "Memorie storiche di Borgomanero e del suo mandamento" (1859; 2nd ed., 1880); "Adria e le sue antiche epigrafi illustrate" (Prato, 1888); "La provincia romana dell' Ossola ossia delle Alpe Atreziane" (Pratom 1892). All these works were collected in a series of "Opere varie" (11 vols., Prato, 1875–92), which also contains numerous memoirs of antiquity and lexicography, the best known being "Della distinzione tra i Britanni o Brittonnni dell' Isola e i Britanni o Brittonni del continente", (Modena, 1867–72). According to de Vit the name Brittany was given to Armorica because some Brythons had established themselves there in the time of Julius Caesar, coming from the east bank of the Rhine. These must have been the Britons, while the inhabitants of the island must have been the Britanni. A confusion of names subsequently arose. This theory has not, however, been accepted by scholars. Another dissertation (1873–74 and 1881), concerning the road of the invasion of the Cimbri, and on the site of the Battle of Aquae Sextiae, also aroused controversy.