In my collection is a recueil which contains two nearly complete annual volumes of the French music periodical Journal des Troubadours Avec Accompagnement de Guitare ou Lyre, for five years co-edited by Ferdinando Carulli and thus also of some significance to guitar history.1 My attention was first caught by an unusual code at the bottom of the first music page of practically all of the issues. This could at first be taken as a plate number, but many of the issues also have a customary plate number as well as the code mentioned. I had never seen this type of code and this of course sparked my interest to do some research on this journal, what this code could signify and what other information the code might...