516 PAPER MAKIXG. 



richer in azote than when encumbered with oil, which has no fertilising 

 properties ; on the other hand, the oil extracted will be found appli- 

 cable to a variety of useful purposes, especially when purified by any 

 of the ordinary means. 



Under a subsequent patent, Mr. Ward combined the wet and dry 

 modes of separation. 



This mixed method, partly wet, partly dry, was devised to remedy 

 an inconvenience met with in working out the dry process. This in- 

 convenience arises from the tendency of wool and other animal matters 

 to become partially converted, under the influence of high-pressure 

 steam, into a glutinous adhesive substance, which impregnates the more 

 friable portion of the reduced animal matter, gluing its molecules to 

 each other and to the vegetable fibres of the mixed material, so as to 

 render the subsequent mechanical separation of the products, and the 

 cleansing and bleaching of the vegetable fibre, more difficult. To 

 remedy this Mr. Ward takes advantage of the remarkable solubility 

 of the glutinous adhesive portion of the converted animal matter to 

 remove this portion in solution, leaving only the less soluble residuum 

 of the animal matter to be separated as a dry powder from the vege- 

 table fibre, by beating, sifting, or other mechanical means. By thus 

 separately withdrawing in solution the glutinous sticky product, instead 

 of allowing it, as heretofore, to dry along with the remainder of the 

 mixed material, the subsequent mechanical separation of the friable 

 from the fibrous parts of the mixed mass is greatly facilitated, seeing 

 that the molecules of the animal powder are no longer glued, as before, 

 to each other and to the vegetable fibre ; again, the cleansing and 

 bleaching of the fibre is also made much easier, because it is no longer 

 imbued and partially encrusted with animal matter. This mixed 

 process can be performed in several ways, and the object being to 

 dissolve part only of the animal ingredients of mixed materials, the 

 choice of a partial solvent is the first consideration. The substances 

 preferred for this purpose, on account of their cheapness and efficacy, 

 are (1) water, and (2) a caustic earthy base, preferably lime. 



If the mixed materials be slightly moistened with water before 

 being subjected to the process of digestion in an atmosphere of steam, 

 and if, after such moistening and digestion they be subjected to pressure 

 to remove from them the dark-coloured solution of animal matter which 

 will flow away, and if, finally, the pressed residuum be then subjected to 

 the remainder of the process, the mixed mode of separation, partly wet, 

 partly dry, will be effected, and the above described benefits of this 

 mode will, to a considerable extent, be obtained. The addition of lime 

 as well as water will, however, be to increase the advantage and dimin- 

 ish the cost of the new or mixed mode of treatment. The lime rapidly 

 attacks the animal matter, combining in particular with the sulphur to 

 form a soluble hydrosulphate of lime 'probably a bi-hydrosulphate). 

 The animal matter thus more energetically attacked, yields, and becomes 



