Here is the picture of the first printed version of The American Crisis
You may notice the first sentence goes:
"These are the times that try men's fouls."
It continues with "The fummer foldier and the funfhine patriot will, in this crifis, fhrink from the fervice of his country..."
Almost every S is an F in this document. I have noticed it only changes S's that start a syllable, but I don't know what it means. The Wikipedia article said nothing about it. I am not educated in Old English, so I would appreciate it if this could be explained to me.
Thank you, and I appreciate your help.
In early printing, the long s and the f are actually two different typefaces. Take a closer look at the long s in the words you quoted, and at the f in the words like of. You should notice that the crossline is actually just a little bit different (It is usually shorter, or only on the left side of the long s character). To get some input from special collections librarians and scholars check out this webpage: http://www.earlyamerica.com/earlyamerica/howto.html
The quotes there are short tidbits on how and why these differences occur. This is common across early printing styles, especially in the 17th and 18th centuries. The article above references the 18th century, since you were asking specifically about The American Crisis.
