Unclear Latin word in 14th c document

[Searcher]

Unfortunately, I neglected to screensnap the sample but for those familiar with classical Latin, I'm trying to work out a scrawly mystery word...

"Cum a??? vadis per aco ..." (the "co" in aco is superscripted)

I'm thinking it might be Cum autem vadis per... ? Or is there a better interpretation for the a-word?


For context, it's the first sentence following a 14th-century point-list of stars/planets.

It quite can be not classical Latin in 14th century. "Cum" here may mean "when" (archaic quum and quom), therefore a-word may be just the preposition "a".
When from waters through (per) aco...