1895 People's Cyclopedia of Universal Knowledge?

I recently acquired a full set, in excellent condition from 1895. They are titled 'People's Cyclopedia of Universal Knowledge' Edited by W.H. De Puy. The set contains all six volumes and there are no torn pages or hand-written notes in them.

As a bonus, there was also a hand-written teaching certificate folded up in one of the volumes dated 1901. Any information on these or their value would be greatly appreciated.

By Lari L.