284 PROCEEDINGS OF THE 



No treatment can be seriously considered which costs 

 more than 25 to 30 cents. Wood is still cheap, and 

 until the original cost of a tie goes to $i or thereabouts 

 cheaper treatments must prevail. Of those advocated 

 I would advise using the best; in other words, consid- 

 ering the investment from the first standpoint, that of 

 annual charges. This would mean either a cheap 

 creosote treatment, one using small amounts of oil with 

 as good penetration as can be obtained, or a zinc creo- 

 sote combination, both of which would cost 20 cents 

 or thereabouts. The risk taken would be a small one 

 because the preservatives have a known value and the 

 original amount would not be a disproportionate one 

 when compared with the cost of a new tie. 



From this brief outline of the kind of preservative 

 to be used, we may pass to some of the results which 

 have been obtained from preservative treatment. While 

 timber preservation has been practiced more or less in 

 this country for many years, it has been carried on in 

 such a way as to give few reliable data. The records 

 which were kept during the early days are very unsat- 

 isfactory, and only very general conclusions can be 

 drawn. In getting together the figures for the coming 

 International Railway Congress, as to results obtained, 

 we went carefully over all records kept by American 

 railroads. 



As a result of our study, we were able to report an 

 average length of life obtained for hemlock ties laid 

 in Iowa, treated with the Wellhouse process (zinc 

 chloride, glue, and tannin), of 10.6 years; hemlock 

 untreated lasts about four years. About the same 

 length of service was obtained in the southwestern 

 states with mountain pine treated with zinc chloride, 

 glue, and tannin. These results are on the whole very 

 satisfactory, for the length of life of these shortlived 



