"Well, then, Daniel Elzevir, in his turn, adopted Minerva and the olive tree as his mark, with the device: Ne extra oleas. You still follow me?"
"Perfectly: Isaac, a vine laden with grapes; Daniel, Minerva and the olive tree."
"Better and better. But, besides these recognised editions, there are anonymous and pseudonymous editions, and there is where the inexperienced bibliomaniacs get confused. Ah!"
"Will you be my Ariadne?"
"Well, these editions are usually designated by a sphere."
"Then that is a guide."
"Yes, but you will see! These brothers, cousins or nephews Elzevir were a very capricious lot of fellows. Thus, for example, one finds, since 1629, a buffalo head forming part of the headpieces in their books, at the beginning of prefaces, dedicatory epistles and text."
"Well, thanks to the buffalo's head, it seems...."
"Wait a bit ... this lasted for five years. Since the Sallust of 1634 and even perhaps earlier, they adopted another sign which resembled a siren. Also in this edition...."