Maker: Ross and Co.
It is probable this set of walnut Balloon Back Chairs by Ross & Co. were made to fit into a Chiffonier such as the one also shown on this website. British Campaign Furniture by Brawer shows a similar set of chairs made by Ross for Captain Simner and his wife as a wedding present in 1863. They were designed, along with a day bed, centre table and easy chair to fit into two cases, which formed a sideboard, when empty. The front legs of the chair unscrew from the seat and the back legs which screw through the seat into the chair back have an additional small thumb bolt to further secure them.
Each piece is stamped with a number which corresponds to its position on the chair, thus ensuring that parts from one chair don't get mixed up with another. These numbers range from 62 and 63 on the first chair to 92 and 93 on the fourth. This type of numbering and the thumb bolts on the back legs seems to be typical of Ross (see also the armchair). Two of the four chairs have the brass Ross & Co label to the underside of the seat and again it seems typical of Ross that not all chairs in a set would be labeled. Third quarter 19th century.
The size of one chair assembled is given.