Much, much thanks! That's the source of it, alright!
Some speculate, based solely on reports of their close resemblance, that Edward Stevens was Hamilton's half-brother.
Cannot imagine a 14 year old writing such a letter. Not the kind of prose I would have written at that age. But then, even his poetry surpasses the maudlin doggerel I did pen at about the same age. And of course, he did pretty much run that counting house. Quite a remarkable person, that Hamilton.
I wouldn't think such prose possible of such an age, either, but remember, children of 200 years ago---who were educated---were educated in letters and math to a FAR greater degree (given what they could be taught) than today. I've seen a state of NJ high school ENTRANCE test from 1891 that would stagger most college graduates.