Of all the photographic sizes that have been introduced to the public, the cabinet is the most artistic in its proportions. As nearly as possible it falls under that art rule of producing an oblong or parallelogram of the most agreeable proportions, which is as the diagonal is to the square. The size of the cabinet is 5-1/2 by 4, and if you measure the diagonal of the square of 4 inches, you will find that the length of the cabinet, 5-1/2 inches, is as near that as possible. Doubtless Mr. Window had this in view when he introduced the size, and whether for upright or horizontal pictures, such proportions are decidedly the best. Many of the sizes already in use are too long, others are too short and square. In addition to the beautiful proportions of the cabinet size, it gives the portrait photographer more room and opportunities to introduce harmonious forms and effects in the posing and arrangements of portraits and groups; and I have seen some very charming views on the cabinet size, 5-1/2 by 4 inches horizontally; as well as some very beautiful interiors of Westminster Abbey, by Mr. V. Blanchard, on the cabinet cards vertical, which proves pretty conclusively that the proportions of the diagonal to the square of any size will suit both vertical and horizontal pictures. I have not the least doubt but a much greater demand for those cabinet pictures, both portrait and landscape, could be created, if photographers would set about introducing them with a will: depend upon it if they will but put their heart into the matter, they would put money into their pockets. I know how much has been done by launching them fearlessly on the sea of public patronage in several localities, and I feel certain the demand would be much more general if the cabinet picture were judiciously introduced. Mr. H. P. Robinson and Mr. Nelson K. Cherrill, having entered into partnership, are on the point of opening a photographic establishment at Tunbridge Wells, where they intend to incur considerable expense to introduce the cabinet portrait, and give it that prominence it so justly merits.