Looks like it says "Mihi Lucra Pericla," pretty close to "mihi lucra pericula" which seems to be translated a few ways, but possibly as: dangers are profitable to me. That motto is on a list of Great Britain family crests if that helps so maybe a livery button.
Update:
Yup, looks like it's the Suttie family crest. In Fairbairn's Book of Crests of the Families of Great Britain and Ireland on page 536 it lists the Suttie family crest as a ship under sail, flagged and rigged, and with that motto.
https://archive.org/details/fairbairnsbookof01fair/page/536/mode/2up/search/suttie
That's an awesome button! Wonder how it ended up here?