Show preservation of thoroughfares washington preservation of the thoroughfares in the yellowstone na dional park Is a subject to which the army engineers having charge are div ing a good deal of attention it is a considerable problem for the reason that the work of sprinkling in cordei to prevent disintegration Is an eapen sive task the cost now being about for sprinkling perhaps not more than miles of road there has been some talk of using oil but this Is necessarily expensive and there is considerable doubt of this method of treating the roads |