Also, is that Jefferson’s original capitalization? I never would have figured him for the type to think he’s too cool for normal capitalization rules.

Here's a picture of it (the first page, anyway, which isn't the same as the part I quoted). It appears that he, indeed, wasn't in the habit of capitalizing the first word of sentences. 'Course, it was so long ago that I'm not sure if it really was a normal rule at the time (especially for handwritten correspondence, as opposed to typeset publications).