These ramblings and musings are based on the scanned text and not on the pretty poor automatic transcription of them.

I don't think (in the first book) that it's a name, because it's not in italics as the other names (of authors) nearby: e.g., Vavass. (is probably Francois Vavasseur, aka Vavassor) who also wrote a paraphrase of the book of Job. The second name is probably Philippe Codurc who also wrote about the book of Job.

I am not sure that the initial letter in the word is a "C" or a "G". It looks closer to a "C". (In the second book, it is a "C". Is it possible your ancestor's name is a Latinized version of the Dutch/Flemish name Gordat, Gordats?

Ceci n'est pas un seing.