286 Proceedings op the 



St. Louis to determine what influence treatment had 

 on the strength of wood fibre. The effect of the usual 

 prehminary steaming was investigated, and also the 

 effect of injecting creosote in varying quantities with- 

 out preliminary steaming. While it is as yet too early 

 for final conclusions, I am glad to be able to state that 

 we have determined very definitely that the injection 

 of creosote into wood has about the same effect as 

 injecting a similar amount of water; in other words, 

 the creosote in and of itself in no way renders wood 

 brittle and weak. We found that the brittleness or 

 weakness was brought about by the steaming operation 

 before the injection of the oil. Steaming at 20 pounds 

 for about four hours did not affect the fibre materially, 

 but when continued for a longer period the wood was 

 weakened. After ten hours of steaming at 20 pounds 

 pressure the wood decreased as much as 26 per cent 

 in strength. The same was true when steamed at 

 higher pressures. 



These results clearly indicate that where the best 

 results are to be obtained as little steaming as possible 

 should be practiced in treating wood with creosote. 

 This will probably hold for other preservatives as well. 



A word should be said here concerning some of the 

 problems dealing with abrasion of treated timbers. 

 No process of preserving will pay if the preserved 

 timber is rendered unfit by being worn out prematurely. 

 The question of tie plates and rail fastenings should 

 receive serious consideration in all discussions on pres- 

 ervation. It so happens that many of the shortlived 

 woods are soft and easily worn. Preservation will 

 protect them against decay, but not necessarily against 

 wear. Recent trials with wooden tie plates have 

 proven very encouraging. Some of these, made of 

 cypress, have been in a main line track for eight months 



