Classic 'In Statu Quo' ('in this current state') travelling set from Jaques. The 'In Statu Quo' set was first patented by Jaques in 1853, the new idea being that play could be halted at any time, and the set folded away with the chessmen remaining in position- ready for continuation of the game at later time.
We can date this particular set to the 1890s by the brass maker's label (see Alan Fersht's "Jaques and British Chess Company Chess Sets", pages 53-55.