88 



The boiling process was conducted in a stationary spherical 

 boiler, and after due treatment, the ley was in most cases rapidly 

 drawn off, and the fibre thoroughly washed in the pan with fresh hot 

 water, and finally the coloured matter completely removed by rinsing 

 in a washer. 



Any use of high pressure involved in the soda process affects the 

 pulp injuriously, the quality of the cellulose, as far as strength is 

 concerned being much inferior to that obtained by digestion at a 

 lower temperature and pressure. It was also noticed that in the 

 latter method of treatment a smaller quantity of bleaching salts were 

 required in order to ultimately attain a fair white colour, and more- 

 over, if this method is adopted the action of the bleaching solution is 

 altogether more rapid. 



At the outset, emphasis is laid upon the fact that the lordinary 

 niethods of bleaching are not very successful, at least, when the 

 results are worked out and viewed from a commercial stand-point. 

 This is an unfortunate matter, as any future development must be 

 dependant upon the establishment of a cheap bleaching process, 

 which is, more especially in this case, an essential feature, in order to 

 counterbalance the characteristic want of '* Natural strength " and 

 felting power of the pulp, which incidentally, bars its use for the pro- 

 duction of a strong paper. 



In describing more fully the process of bleaching in connection 

 with this pulp, a curious and interesting fact was noticed, i.e., that 

 the acid treatment in bleaching, which is the usual method of pro- 

 moting the action of the bleaching solution, tended to spoil the colour 

 of the half-stuff, so that in order to obtain the best possible results 

 any operation inYolving the use of acid must be altogether avoided. 



The natural tint of the fully-bleached pulp is of a faint greenish 

 white, and the employment of a very small quantity of aniline dye is 

 found necessary to impart a good colour to the finished paper. 



The application of some improved methods for bleaching the 

 crude pulp resulted in the production of a much superior material, 

 but with no great saving in chemicals or working expenses ; and, it 

 appears certain from a large number of experiments that this fibre 

 cannot be effectually bleached at a consumption of less than 8%-io% 

 of chlorine. Therefore, instead of attempting to bleach to a full- 

 white, the paper was invariably tun after the expenditure of a reason- 

 able amount of bleaching agents on the pulp, with due consideration 

 for the proportions of other chemicals already used on the amount of 

 fibre under treatment. It is safe to say, however, that although Lal- 

 lang when run quite alone is not very promising as regards colo^^r, it 

 makes some papers of particularly good quality and finish, when 

 mixed with various other Winds of furnish. A number of the most 



