via Now I Know
“There are 26 letters to the English alphabet, with two of the letters — ‘A’ and ‘I’ — themselves also constituting words. But as seen to the right, another character — the ampersand (&) — also, at times, was included among the current 26. And amazingly, the word ‘ampersand’ is probably a byproduct of the symbol’s inclusion. The picture here is from a 1863 book called ‘The Dixie Primer, For The Little Folks,’ — a book which like many around even today, aimed at teaching children their ABCs and some basic words and phonics. Notably, the ampersand is included in the alphabet, just next to the Z and ending the entire set. While not necessarily the standard usage, it was not terribly uncommon either to include the ampersand here — it had been there for centuries…”
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