What is a "permusementor?"

The Frederick County (MD) Mailing list had a query recently noting that (I tried to find this in the MD-FRED-GEN Archives, but it was down tonight):

"The Diary of Jacob Englebrecht published by the Historical Society of
Frederick County, Inc. has the following entry.

“'Well Bill, what did you see,' said old Ben Linton to his son William as he
had just returned from Baltimore. 'Sha' said Bill, 'I saw something they
call 'forty-five per anum' and if I was as good a permusementor on it, as
that man was, I would not take fifty dollars for my larning'. Mr. William
Jenkins Junior is my author. Jacob Engelbrecht Monday April 29, 1822 6 o'clock PM."

And then the poster asked the question - what is a "permusementor?"

'Tis a puzzlement to me also. The way it reads, it might mean someone with financial acumen. I Googled "permusementor" and got no hits. I Googled "permuse" and found no definition of an English word, but it seems to be a word used in Italian, probably meaning "to think". I checked the "Stories and Publications" database on Ancestry.com and had no matches.

Then I realized that there were three smaller words in it - "per," "muse" and "mentor." I looked for definitions for those words and found (among several, I chose these):

"per == "to" or "for"
"muse" == "to think reflectively, ponder, or meditate"
"mentor" == "a wise and trusted advisor or guide."

So putting them together you might define "permusementor" == "a wise advisor who ponders or reflects." Perhaps even "a thinking wise man." But that's an oxymoron, I think. It may be a word that was used in a small area based on some wise guy (lawyer?) trying to impress the populace.

Does anybody else have an idea? Obviously, there will now be an entry for "permusementor" when someone else Googles it in the future! I need to try to use it in my presentations to really impress (or confuse) the attendees.

Anyway, the "Diary of Jacob Engelbrecht" looks interesting!