598 Forestry Quarterly. 



Soluble Insoluble Non Tanmn 

 Solids. Solids. Tannins. 



Quercus marilandica . . . 17.23 



Q. texana, 13.37 



O. velutina, 22.81 



Q. alba, 16.37 



Q. digitata, 18.68 



Q. minor. 18.43 



Blends are often necessary to secure good results as in the 

 case of the bark of the black oak group, which used alone 

 would produce a harsh stiff leather, while when blended with 

 chestnut and oak or hemlock tannin will give good results. 



Hardwood Record, July, 1913. 



Forest service officers report the following 

 Durability percentages of removals of ties from a 



of test track on the Northern Pacific Railway, 



Cross-ties. after 6| years service. 



At Plains, ^lontana. 



Douglas Fir, green, 75% removed 



Douglas Fir, seasoned, 77% removed 



Tamarack, green, 97% removed 



Tamarack, seasoned, 93% removed 



Both species treated with zinc chloride, 2% removed 



At Maywood, Washington. 



Douglas Fir, green, 37 % removed 



Douglas Fir, seasoned, 27.5^ removed 



Douglas Fir, creosoted, 2.5% removed 



Hemlock, green, 92-5% removed 



All removals of treated ties were due to mechanical failure 

 and not to decay. 



Timberman, July, IQ13. 



