Such easy stuff latin. It means: I cousin Tristissimus relinquish (all I own to the) seventh child.

Well, one of the words in Latin for 'cousin' is consobrinus (the child of a mother's sister). Cosus doesn't really mean anything in Latin. I asked about the tilde over the o because that was a medieval convention for marking a vowel followed by a nasal.

Septem is 'seven', not 'seventh'. Infantulos is plural and in the accusative case. For a stretch, if the word transcribed as reliquil is a verb of some kind, septem infantulos could not be an indirect object, but it could be a direct one. "He Xes the seven babies."

If the commas are there in the original, they don't make much sense. Was there more? You should have paid the couple of pfennigs and printout out the page from the microfilm.

Ceci n'est pas un seing.