438 Transactions of the Canadian Institute. [Vol. VII. 



Stored material. In the pine family there is stored in the wood and 

 bark cells an abundance of crude turpentine and resin. The Norway- 

 spruce of Europe furnishes in this way turpentine and Burgundy pitch. 

 The yellow pine of the Southern United States yields spirits of turpen- 

 tine by distillation of the crude turpentine which runs away from the 

 tree by cutting into it. The residue after the distillation is resin. 



Noa^ the poisonous material in sawdust must be either the cell wall 

 or the stored material. It cannot be the cell wall, for this is just the 

 wood fibre or material used in making paper, and pure paper is cer- 

 tainly not harmful to fish life. The poison can scarcely be anything 

 else than the turpentine and other substances stored in the cells. 



Different trees, such as tamarack, pine, cedar, spruce, etc., generate 

 and store different kinds of reserve material. When a log from one of 

 these trees is cut into boards, the sawdust gives off proportionately 

 much more poisonous matter than the slabs, edgings and bark. The 

 reason of this is easily understood. As each cell or vessel is micros- 

 copic, and contains only a very small quantity of poison, and as the cell 

 wall must be broken open in order to let out the contents, it follows 

 that the greater the number of cells that are opened, the greater will be 

 the quantity of turpentine, resin, etc., poured out. Hence, a saw log 

 converted into sawdust, or ground into shreds, as in a pulp mill, gives 

 out the maximum of poison ; whereas a similar log sawn into boards, 

 edgings and slabs, will give out a much less quantity. The minimum 

 will be given out by a saw log floating in the water. 



The total waste in manufacturing saw logs into boards is some- 

 times stated as equal to the lumber obtained for market ; but this is a 

 gross exaggeration. Prominent manufacturers like the Rathbun Co., 

 W. C. Edwards, M.P., and J. R. Booth estimate the waste as varying 

 between 25 per cent, and 35 per cent, of the whole log. The proportion 

 of refuse varies with the size of the logs, with the kind of lumber into 

 which the log is cut, and with the kind of saw used in the mill. The 

 old-fashioned gang saw and the large circular saw produce a higher 

 percentage of waste than the more modern band saw. There is more 

 waste in cutting a log into inch boards than into 3-inch deal, and small 

 logs produce proportionately more waste in bark, slabs and edgings than 

 large logs. The waste in sawdust alone varies from 10 per cent, to 20 

 per cent. 



