during 1917 and 1918, and although some reaction will doubtless occur, there seems little doubt that chrome sole leather has taken a definite and permanent leap forward. Once the general public fully appreciate its qualities of waterproofness and durability its future will be assured. On the whole the position and prospects of chrome tanning are good. The chrome tannages are making headway in all directions, and undoubtedly threaten the existence of many of the older processes of vegetable tanning. REFERENCES. Procter, "Principles of Leather Manufacture," pp. 198-220. Bennett, "Manufacture of Leather," pp. 210, 355. Bennett, _J.S.L.T.C._, 1917, 176. Stiasny, _Collegium_, 1908, 117. SECTION II.--GENERAL METHODS OF CHROME LEATHER MANUFACTURE It has been previously pointed out that the chrome tannage is an "empty" one; the primary principle in the wet work of goods for chrome leather is to avoid anything which will make this feature more obvious. In the vegetable tannages relatively larger amounts of the tanning agents are used, and these fill the interfibrillar spaces; indeed, as we have seen (Part I., Sections III., V. and VI.), effort is made to increase these spaces and to fill them to their maximum capacity, thus yielding a leather of which 50 per cent. is the tanning agent. In chrome tanning, however, the tanning agent may only be approximately 5 per cent. of the finished leather, so that any trouble taken to split the hide fibres or to dissolve hide substance is usually not only superfluous, but also calculated to enhance the "emptiness." The governing principle of all the preparatory processes for chrome tannage is therefore the conservation of hide substance, and this principle determines the modifications of the processes of soaking, liming, and deliming, which are in vogue. Now, in most of these processes there is usually some loss of hide substance, and it is the particular problem of chrome tanning to reduce this loss to a minimum in each stage. Whether the loss of hide substance be due to alkaline or fermentive hydrolysis, or to solation of the hide gel, the effect is increased by swelling, and in the wet-work for chrome, therefore, any variations in the degree of swelling are objectionable. The preparatory processes should be carried out with as little change as possible in the volume and elasticity of the pelt. Whether also the loss of hide be due to hydrolysis or solation, it is increased by time, hence short processes are (other things being equal) much to be preferred. Fermentive hydrolysis is minimized by cleanliness, alkaline hydrolysis by avoiding strongly alkaline liquors, and solation of collagen is reduced by both, and also by avoiding, as far as possible, the presence of calcium and ammonium salts. Soaking should be quick and clean. The use of the paddle or drum gives the greatest efficiency and also assists in procuring the softness so essential to the bulk of chrome leathers.