hauser bought an old primer which he thumbed it on at the edges what does it mean - English - The Last Lesson

Question

hauser bought an old primer which he thumbed it on at the edges
what does it mean?

Saronik Bosu · Accepted Answer

It being the last French lesson, the villagers had come to the
school, to M Hamel's class for the occasion Hauser was an old man
who was long past his school days, but the imminent prospect of
having to give up on his beloved French language for German which
was being imposed by the Nazi government, made him both nostalgic
and patriotic To participate in the last French lesson, to steep
himself one last time in the beautiful language, he brought a
primer (a book used in the elementary levels) and sat thumbing it
on the edges

hauser bought an old primer which he thumbed it on at the edges what does it mean?