What does the "at" symbol in a catalog of movable type from the early 1900s?
The so-called @ - in Italian "a commercial" (at in the Anglo-Saxon world) was actually born in the mists of time, initially used with the most diverse meanings (abbreviation of amen; graphic synonym of Addì, of "versus", of "ante", of "aut" etc.) and therefore adopted by Tuscan and Venetian traders of the 16th century with the intention of graphically representing "the amphora", the unit of measurement and capacity in use at that time.
The survival of @ to this day is due to its use in the Anglo-Saxon commercial world with the meaning of "at - the price of" (at the price of) and its inclusion for this purpose in the keyboard of the first American typewriters of the '900.
It will be Ray Tomlinson in 1971 who chooses it from that selection of characters for its meaning of "at" (precisely) for the e-mail addresses of ARPANET, the experimental university network from which the internet descends.
Unlike the & (ampersend) in the catalogs of Type foundries the @, where proposed is inserted among the "signs" and never compared to real alphabets given its absolutely technical character and its graphic immutability, although this logogram also probably descends from a Latin abbreviation of two letters "ad".