Mobilis in mobili

[Aronnax]

Hello connoisseurs,

my question is about Nemo’s motto in Vingt mille lieues sous les mers. Jules Verne and his editor, Hetzel, discussed it, and Hetzel asked a specialist. He answered that "mobili" was right, whereas "mobile" was wrong:
"The adjectives ending in "bilis" do not have two endings in the ablative case, but only one: -i."
I hope my translation is correct. Here’s the original French:
« Mon cher Hetzel, M. Vernes (sic) se trompe, et vous êtes dans le vrai. Les adjectifs en bilis ne sont pas de ceux qui admettent la double terminaison à l'ablatif. Il n'en ont qu'une: celle en i. Ce n'est pas vous et moi seulement qui le disons: c'est tous ceux qui passent leur vie à faire du latin, et mon frère en premier dont j'ai eu soin à prendre l'avis quant à ce. Tout à vous, J. Quicherat » (BnF, NAF 16985, f° 206).
<http://mobilismobile.free.fr/accueil/mobili.php>

On that page, they have a link:
https://web.archive.org/web/20051016041146/http://www.artsculture.education.fr/presence_litterature/jules_verne/dossiers/latiniste.asp
They seem to say the opposite:
""mobile is the ablative of a masculine or neuter noun, and "mobili" that of an adjective: this variation [or variant?] does not seem to mean anything [or: seems to be insignificant?]; it may be a glitch."
«… il avait donné à son sous-marin un nom latin, le « Nautilus », et choisi une devise latine, « Mobilis in mobile ». C’est la forme qu’on lit dans l’édition de 1871, mais dans l’édition de 1880, la devise est « Mobilis in mobili » (« mobile » est l’ablatif d’un nom masculin ou féminin, « mobili » l’ablatif d’un adjectif : aucune signification ne paraît s’attacher à cette variation, peut-être involontaire) :

Mobile dans l’élément mobile ! Cette devise s’appliquait justement à cet appareil sous-marin, à la condition de traduire la préposition in par dans et non par sur.

»

Page:Verne - Vingt mille lieues sous les mers.djvu/67 - Wikisource

fr.wikisource.org

Can you shed some light on this? I’m looking forward to hearing from you

Best wishes
Matthias

 

[Hector]

This is too complicated for me to answer confidently! Please forgive my uncertain attempt to provide some information.

I'm not sure because variability is often found between ablatives in -ī and -e in Latin. The rules that do exist, such as the use of -ī for i-stem neuter nouns, often have exceptions (e.g. mare exists as an ablative form of mare, despite the i-stem plural maria).

I think I prefer -ī in this case, but I'm not sure whether -e is definitely incorrect.

If there were a following noun, mōbilī would clearly be an adjective used adjectivally and the ending -ī would certainly be correct. Explaining mobile as "l’ablatif d’un nom masculin ou féminin" seems questionable to me, but I can't explain why, so I could be wrong about it. Allen and Greenough's "Summary of I-stem forms" includes one list of "adjectives used as nouns" that exclusively take the ablative in -ī (aequālis, annālis, aquālis, cōnsulāris, gentīlis, molāris, prīmipīlāris, tribūlis) and one list of "adjectives used as nouns" that sometimes take the ablative in -ī, and sometimes in -e (affīnis, bipennis, canālis, familiāris, nātālis, rīvālis, sapiēns, tridēns, trirēmis, vōcālis).

 

[Aronnax]

Thanks a lot! At least one thing seems to be clear: "Mobilis in mobili" is correct, with "mobili" being an adjective used as a noun, in the ablative case.

(And if Quicherat is right, the adjectives that have the ending "-bilis" always have "-bili" in the ablative case, so "Mobilis in mobile" would be wrong.)