The study of handwriting is called palaeography.

You could probably do with looking back a bit further than the Revolutionary War, especially if you're interested in how utensils and mediums affected the script.

Here is a wonderful website which goes through about 1500 years of script development.

The most important development, in part cultural and in part pragmatic, can be most clearly demonstrated by opening a word document and using the (once default) Times New Roman font. Now compare that to this script. Similar aren't they? In fact TNR is based on this script. Carolingian Miniscule was a renaissance of Roman script built partially on the veneration of Rome under Charlemagne and a need to replace the horrible chancery script (ie. government records) of the Merovingians. This clear and legible script was incredibly popular into the twelfth-century when the proto-Gothic script began to emerge. Proto-Gothic is fancy and was usually reserved for rather expensive books. It's still clear and legible but has some more ornate features than the documentary Carolingian script.

Then things went rather to pot. The medieval script most of us are familiar with, Gothic, became popular in the thirteenth-century and would remain popular for three hundred years.

The humanists, again fascinated by Rome, revived a script based on the Carolingian miniscule

There appeared, concurrently, 'chancery' scripts which tended to be somewhat more practical than 'book' scripts. This was in part because they needed to be written quickly and would be heavily abbreviated to save on valuable space and parchment. Here is an example of an English documentary script contemporary to Gothic.

Have a look around the rest of that website for more information, and for a beautifully illustrated and informative coffee-table style book consider purchasing:

Michelle P. Brown, A Guide to Western Historical Scripts from Antiquity to 1600, London, 1990.