NEW BRUNSWICK FORESTRY CONVENTION 95 



separate the individual fibres of the wood by tearing them apart. The basis 

 of the chemical fibre is to be found in the well-known action of certain chemi- 

 cal re-agents which disintegrate the original structure by a process of chemi- 

 cal solution, to such an extent as to permit complete separation of the fibres 

 without destroying them. The action must, therefore, be carefully controlled. 

 Of the chemical pulp, two varieties are recognised according to the particular 

 method employed. In many of the mills of the United States, and in some 

 of the Canadian mills also, soda pulp is manufactured. This depends upon 

 the action of sodium hydrate, which requires to be recovered from the liquor 

 after action upon the wood, in order that it may be used again. With this 

 process we shall not particularly concern ourselves at the present moment. 

 Other mills produce what is known as sulphite pulp. This results from the 

 action of sulphurous acid upon the wood structure, and the low cost of the 

 re-agent does not necessitate its recovery, hence the waste acids imply passes 

 off in the wash, the entire process is greatly simplified, and the cost reduced. 

 At the mill which has been selected as our type, only mechanical and 

 sulphite pulps are made. 



In order to fully comprehend the reasons for the two methods of manu- 

 facture thus briefly indicated, it will be necessary to digress slightly and 

 make a brief study of the wood from which pulp is made. It has already 

 been pointed out that pulp may be made from quite a number of kinds of 

 wood, but in Canada practically only one kind is employed. If we watch 

 the logs as they pass from the yard to the saw mill, it will be seen that the 

 bulk of them represent spruce, while occasionally a balsam log appears, and 

 accidentally also, hemlock may find its way into the mill. The latter is 

 never introduced by design, and its presence is at once detected in the vari- 

 ous processes through which it must pass. On economic grounds, balsam is 

 used to a certain extent in the manufacture of pulp designed for local con- 

 sumption at the mill, but the presence of a large amount of resin makes it an 

 undesirable material for pulp, snd it is carefully excluded from all pulp de- 

 signed for the market. It thus appears that spruce is the only wood used 

 for merchantable pulp. Two species of spruce flourish in Canada, and serve 

 as the source of pulp wood. They are known as the white spruce (Picea 

 alba) and the black spruce (Picea nigra). Structurally they differ but little 

 from one another, but speaking generally the cells of the black spruce have 

 thicker walls than the white, and this is probably the basis of the preference 

 which is given to the former as we shall see more particularly, presently. 

 It is probably for a similar reason that the compact and tough wood from 

 the northern districts of the Saguenay is preferred to that which comes from 



