That might sometimes be so, Uncle; but certainly not always, at least in eighteenth-century typography. I know for certain that the kind of "f"-seeming letter you describe - lacking half of the crossbar, incidentally - would be used at the beginning of a word where we would now use an "s", as long as it were lower-case. It wouldn't be used at the END of a word, where common "s" would be used, and if there were two "f" letters in the middle of a word ("dissent", for instance) only the first of these gets the long shape; thus, "difsent". Sometimes, this practice can provide rather interesting results to a modern reader, and I find it impossible to think that contemporary ones didn't spot something like this, which appears in one of Allan Ramsay's Epistles to William Hamilton of Gilbertfield:

"Of Poetry, the hale quintessence
Thou hast suck'd up, left nae excressence...."

And here's me only looking in to see had anyone made any comment on "ornamentation".