These two stamps show the development of one form of library stamps. Both stamps belong to the same library, the cantonal library of Grisons, in he Swiss mountains; both are used on the same series of booklets (the annual reports of the cantonal commission of school libraries and public libraries in the canton of St. Gall), but in different years.
The first one is from the 1977 annual report. It is simply the name of the library, with the name of the town of Chur highlighted in stronger letters. Besides that it uses a simple blue as ink and no other decorations.
The other one is used on the 1983 annual report (the first one in this series with this stamp). Here, the library changed the stamp. It is now marked by a borderline and includes more information on the library itself, namely the adress. (Were the library still is situated today.) The stamp makes itself more clear as a library stamp, while the other one could have been overlooked as a publisher signet.
Now this booklet could be send back to the library. (Which is not meanigful on this booklet, at it is only for inhouse use; but could be handy for other books.)