Russia leather is calf prepared with willow bark and scented with birch oil. It is a modern leather, and lasts badly, and is generally diced,--that is to say, covered all over with diagonal rulings. It was a favourite leather of Roger Payne’s. It is said that a book bound in Russia leather will last better if much used, and no doubt this is true, not only of Russia but of any other leather. As a rule leather bindings in libraries are starved; they get dry, and readily absorb animal oil from the human hand. The truth of this may be found in the fact that numbers of dictionaries and books of reference were preferentially bound in Russia leather some thirty or forty years ago, and whereas unused books bound at the same time in the same way now show rotting leather, the reference books which have been continually used are quite sound and supple. Cow hide is like a magnified calf leather, and shows a slightly pitted surface. It is not often used, but is of much value for very large books that are worth full binding, as one piece of hide could be cut large enough, for instance, to full-bind the _Skibbereen Eagle_, one of the largest Irish newspapers. It would take three or four of the largest goat skins to do this, and it is always advisable to avoid joins, wherever possible, in a binding. But there is one drawback to the use of hide for binding: it is practically impossible to cut it smooth; however skilfully it may be pared, when it gets on the book it is always ridgy. This is, of course, not very important, but it militates against the use of hide except when absolutely necessary. For the rest, hide takes colour well, and it is a very handsome leather, and when it is finished simply with very broad gold fillets it is very ornamental. Pig skin is perhaps the most familiar of all bookbinding leathers to the outside world, because saddles are made of it. It is a thick, rich leather, and, so to speak, full of life. It is not suitable for small books, but very good for large ones, and has been used in England off and on for a long time, but never very much. Charles Lewis executed some fine examples of his larger bindings in pig skin, but I think he never cared much for it. Pig skin responds admirably to treatment with lime, the same method of preparation as used for vellum; and this white “vellumised” pig skin has always been the most favoured material for the covering of fine German books of the fifteenth, sixteenth, and seventeenth centuries. Many of these bindings are perfect in their way, covered all over with delicate roll stamps showing marvellous definition and clearness on the hard white surface. Fine though all their impressions are, it cannot be denied that they are difficult to see; the impressions are shallow, and indeed the designs can often be more easily made out by help of a rubbing with heelball on soft white paper than by examining the binding itself.