BRUNSWICK FORESTRY CONVENTION 97 



it much more highly about ten times more. We are now enabled to see 

 that each wall separating adjacent cavities, is in reality composed of three 

 parts one of which belongs to each of the cavaties, \\hile the third lie, 

 between and seems to cement th^m together. Whatever process is employ ed 

 ^he great object to be attained is to so break up this middle layer as to com- 

 pletely separate the layers on either side. In the mechanical process this is* 

 accomplished by simply tearing the cells apart. In the chemical process thet 

 chemical agent employed is designed to attack the middle layer and bring 

 about its solution to such an extent that the adjacent walls may be separated 

 with the minimum of injury. The general nature of these processes and 

 their results will appear shortly, but for the present we may return to a 

 study of the further changes which our logs undergo after leaving the bark- 

 ing room. The logs destined 



GRINDING ROOM 



for the manufacture of mechanical pulp are now conveyed to the grinding 

 room where there are twenty-seven grinders, each of which is provided with 

 three or four hoppers. The grindstones are of very fine quality and are im- 

 ported from Newcastle, the necessary supply for an entire year being pro- 

 cured at one time. Each stone presents a grinding face of twenty-six 

 inches of which only twenty-four are actually utilized. In the process of 

 grinding the blocks of wood are fed into the sides of the hoppers and held 

 firmly against the face of the stone by hydraulic pressure. As the pulp 

 issues from the base of the grinders, it is carried to a screening trough 

 where the finer parts are separated from the chips. Thence it passes to the 

 screening room where it is carried over a series of very line screens which 

 finally determine the fineness of the fibre. The 



PRESS ROOM FOR WET PULP 



now thoroughly washed and screened material passes into the room where it 

 is carried through a series of roller presses from which it emerges in the . 

 form of wet sheets about 4-25 of an inch thick. These are then folded and 

 baled and in that form constitute the wet pulp of commerce. No attempt is 

 made to dry the pulp beyond the point at which it emerges from the presses, 

 and it therefore goes into the market with 60% of water. 



GROUND WOOD FIBRE 



An examination of this wet pulp will enable us to understand the 

 specific action produced by the grinding. The photograph before us shows 



