Current Literature. 



77 



ties in one charge. The aim should be to treat all ties in a charge 

 with approximately the same amount of preservative. 



"(i6) At present it is not known definitely what presen^ative 

 or process is most economical in all cases. Under heavy traffic, 

 where the ties wear out before they rot, treatments with zinc 

 chloride or light treatments with creosote may be advisable. 

 When the traffic is light, heavier injections may be better. If 

 the ballast is wet or moist, creosote is to be preferred to zinc 

 chloride. 



"(17) No matter what kind of ties are treated or what pre- 

 servative is used, at least all of the sapwood and as much of the 

 heartwood as possible should be impregnated with the preser- 

 vative. 



"(18) If ties are to be treated with zinc chloride, and absorb 

 the preservative readily, the solution should be made dilute, and 

 as much as possible injected. This is better practice than having 

 the solution more concentrated and forcing only a limited amount 

 into the outer fibers of the wood. 



"(19) The treating plant should be in good operating condition 

 before any ties are treated. Leaky valves and pumps should not 

 be permitted, and all gauge scales should be accurate and the 

 pulleys and floats running free. After treatment the excess pre- 

 servative should be returned to the same measuring tank from 

 which it came, and the reading corrected for temperature if neces- 

 sary. If the float system is used, the amount of absorption should 

 be determined by measuring the difference in the height of the 

 float before the preservative is run out of the tank and after it 

 has been returned to it. 



"(20) While track scales are generally desirable for deter- 

 mining absorption, they can not be depended upon if the ties are 

 to be steamed or boiled in oil. 



"(21) As the composition of the preservative is very likely to 

 change after a number of treatments, it is highly desirable to 

 have it analyzed frequently to see that it meets the specifications. 



"(22) Creosoted ties which are not to be used immediately 

 should be piled solidly (9x9), while those injected with zinc 

 chloride should be openly piled, to permit of rapid seasoning. In 

 doing this the precautions against too rapid seasoning should be 

 observed. Zinc-treated ties should be seasoned before being 



