larger pieces are screened out and out again so that tha 

 chips conveyed by the automatic elevator to the digester may 

 be of OP nearly a uniform size as possible. 



Digesting is the process which separates the wood 

 fibers and turns the wood into pulp. The Ploriston Pulp 

 and Paper Company uses what is known as the "sulphite pro- 

 cess". A 7.-eak acid is nade by burning sulphur, collect- 

 ing and cooling the fumes and letting them run through a 

 finely ground mixture of lime and mangenese dioxide. The 

 acid is stored until needed end then pumped into the 

 digesters. These are large iron tanks twenty feet in 

 diameter and 4<. feet high. Here the chips and acid are 

 steam cooked for six hours. During this time part of the 

 wood cells and the substance joining them together are 

 dissolved away and the long clean fibers are separated. 

 After six hours cooking the mass is blown out into chests 

 beneath the digesters and is now known as wood pulp. 



The "mechanical process" is also used at this 

 mill. The wood la barked as in the "sulphite process", 

 but instead of being fed into the chipper the blocks ar 

 put into grinders. These are large swiftly revolving 

 jrindstones over which runs a constant flow of warm v;ater. 

 The wood is ground and screened to extract the chunks, and 

 the pulp IE ready for manufacture into paper. This pro- 

 cess, however, does not secure the long fibers which form . 

 the groundwork, but makes a soft mass which acts as a fil- 

 ler and smooths out the paper. If moro of the "sulphite 

 process" or long fiber pulp is used a strong tough paper 

 is secured. If a large percentage of the "mechanical pro- 

 cess" pulp is added a weaker but heavier paper is produced. 



The water is squeezed out between rollers and when 

 a sheot about four feet thick and six feet long is rolled 

 out it is cut off and folded up until it is about two feet 

 square. These wraps as they are called are stored until 

 needed. 



The next process is the mixing of the two kinds 

 of pulp in desired proportion and the addition of sizing 

 and coloring matter. A machine called a beater is used to 

 do this. It is made up of a large steel tank twelve feet 

 wide, twenty feet long and four feet high in which there are 

 two swiftly revolving rollers enclosed in a sheot iron case 

 and covered with dull edged knives running in opposite di- 

 rections. The wraps are throvm in and passing between the 



-13. 



