This stamp (on the left-hand side) is from the Gymnasium Zeitz, a city in Saxony-Anhalt in Germany. As there are more than one gymnasium in this town today, we are not able to say to which one it actually belonged, if any. Still, the stamp must have been printed on the journal in the 19th century, as the “Zeitschrift für mathematischen und naturwissenschaftlichen Unterricht” (Journal for mathematical and natural sciencentific education) started in 1870 and the current example is the eleventh year (1881). Furthermore, the handwritten text below the stamp is in Sütterlin, the historical form of German handwriting, which is not taught anymore in our days.
The original stamp with its rectangle form and the double lined border is more elaborated than other simple lined stamps. The mention “ungültig” (engl. invalid) across the first stamp indicates that the stamp of Zeitz is not in effect anymore. It can be assumed that the journal was removed from the collection. However, there is no mention of its elimination, but only the mention of invalidness.