6i6 THE POPULAR SCIENCE MONTHLY. 



the ties were sound, and would not be called decayed. In the yellow 

 pine the spikes check and separate the. annular rings, which permits the 

 entrance and growth of the mycelium of its special fungus, and this 

 weakens the fiber and loosens the spike. In white oak and chestnut 

 the layers separate by breaking through the small tracheids surround- 

 ing the ducts (see Fig. 3, August number), those of the chestnut more 

 rapidly. The fermentations are retarded in these woods by the tannin 

 in the cells, but they take place eventually, softening and injuring the 

 fibers around the spikes and under the rails. 



In ties which are well treated, so as to preserve them, the fermen- 

 tations are held in check, and the softening of the fibers is prevented, 

 and their durability and consequent wearing capacity are increased. 

 This is an advantage so important that its full benefits can not be ap- 

 preciated until actual comparisons are made between treated and un- 

 treated ties under similar conditions of service. I have parts of treated 

 ties of over thirty years' service under heavy traffic, trebling their or- 

 dinary life, while there are numerous instances in which the oak has 

 doubled its life, and the hemlock has given from five to six times its 

 usual service. 



The durability of well-treated ties is well established in this country 

 by considerable experience on various railways. In England, France, 

 and Germany the experience is ample, the ties lasting there longer 

 than we can expect them to last here, from the fact that chairs are 

 generally used to hold the rail and distribute the weight to a greater 

 area of wood than is the case with the base of our rails ; and, besides, 

 the tonnage per car-wheel is less than ours. It is our freight-cars, 

 with limited spring action, which cause a large portion of the abrasion 

 of the ties. The economy would be great that would result to the 

 railways by prolonging the life of their ties by treatment ; this fact 

 was realized long since, but in putting it into practice the information 

 and experience were not sufficient to enable their engineers to secuie 

 the anticipated beneficial results. In fact, much of the treatment has- 

 tened the decay of the ties and timber, or, when overdone, destroyed 

 their strength. This need be the case no longer, for the study of many 

 of these failures has given much of the information needed, and the 

 experience in treating wood is now extensive. The cheaper grades, 

 such as the beeches, maples, birches, elms, and hemlocks, having a 

 structure sufficient to sustain a heavy traffic, can be treated and substi- 

 tuted at less expense than the first cost of untreated white oak or yel- 

 low pine, and have a greater durability. This would effect an imme- 

 diate-economy in the renewal of ties. 



It would be decided economy to treat the higher-priced ties, so as to 

 double their durability. A general example is given of a mile of track 

 on a trunk line, where 2,800 ties are used per mile : This year the ties 

 cost fifty-five cents apiece ; to lay them in the track costs fifteen cents 

 more, and their average life will be seven years. To treat these ties 



