In 1941 Pietro S. Pasquali and, after he died, Angelo Zabatta published the Vocabolario valdostano by Costantino Nigra. Pasquali edited this work on the basis of a 128 page volume - now lost - that had presumably been written by Nigra before 1896 and was held at the time in the Ascoli Archive at the then Biblioteca Civica in Milan, which was partially destroyed in 1943. A careful study of unpublished documents kept at the Biblioteca Ambrosiana in Milan shows that the vocabulary edited by Pasquali was not based on the final version arranged by Nigra for publication. Further unpublished documents and two letters between Nigra and Graziadio Isaia Ascoli reveal that in the first months of 1905 Nigra asked Carlo Salvioni to help him finish his vocabulary. Unfortunately, at the end of September 1907 the publishing house went bankrupt, meaning that Nigra's manuscript was never printed and was lost.