20 BULLETIN 606, U. S. DEPARTMENT OP AGEICULTUEE. 



penetrated the wood very readily both in the penetrance and cylinder 

 treatments. The penetrance was especially uniform in this species 

 and the oil apparently reached all parts of the wood structure. 



Beech, red-heart (Fagus airopunicea). — Red-heart beech contains 

 numerous tyloses in the heartwood and few in the sapwood. This 

 wood was found to be very difficult to penetrate. Specimens treated 

 in the cylinder showed only a very limited end penetration. A very 

 small amount of creosote was found in the vessels and little or none 

 in the wood prosenchyma. The difficulty of penetration seems to 

 have been caused by the abundant tyloses found in the pores of the 

 wood and by the infiltrating substances in the fiber walls of the " red 

 heart " portion, which apparently prevented penetration in these 

 elements. 



Birch, sweet (Betui-a lento) — heartwood. — The fibers in sweet 

 birch are thick-walled, and gummy substances are frequently found 

 in the wood. Tyloses are not found in either sapwood or heartwood. 

 Specimens treated in the cylinder were well penetrated even at low 

 pressures. Penetration was found to be well distributed throughout 

 the wood structure. The wood prosenchyma was fairly well pene- 

 trated, but creosote was present to a greater extent in the vessels. 



Birch, yellow (Betula lutea) — heartwood. — Yellow birch contains 

 no tyloses in either sapwood or heartwood. The pores were very 

 easily penetrated in all of the tests. In the penetrance tests the pre- 

 servative penetrated to the ends of the sticks almost immediately 

 after pressure was applied. In the cylinder treatments the "vessels 

 were easily penetrated when the wood was merely immersed in the 

 preservative for an hour. When pressure was applied both the ves- 

 sels and wood prosenchyma were thoroughly treated. 



Birch, red (Betula nigra) — heartwood. — The pores in red birch are 

 somewhat larger than those in sweet birch. The wood fibers are 

 fairly thin-walled and there are no tyloses in sapwood or heartwood. 

 As in yellow birch, the vessels were rather easily penetrated at low 

 pressures. At pressures of 50 pounds or more both the vessels and 

 wood prosenchyma were well penetrated. 



Cherry, wild red (Prunus pennsylvanica) — heartwood. — Wild red 

 cherry does not contain tyloses. The wood was treated very easily 

 and was found to be fairly well penetrated when merety immersed 

 in the preservative for an hour. Penetration was complete in prac- 

 tically all of the treatments made. 



Chestnut (Castanea dentata) — heartwood. — The pores in chestnut 

 are numerous and are more or less filled with tyloses in both sapwood 

 and heartwood. This species was very difficult to penetrate both in 

 the penetrance apparatus and in the cylinder. Specimens treated in 

 the cylinder showed very little radial or tangential penetration. The 

 tyloses appeared to close the vessels, so that only a very limited pene- 



