Page:Historic highways of America (Volume 15).djvu/174

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CHAPTER IV

THE SELECTION OF MATERIALS FOR MACADAM ROADS[1]

NO one rock can be said to be a universally excellent road material. The climatic conditions vary so much in different localities, and the volume and character of traffic vary so much on different roads, that the properties necessary to meet all the requirements can be found in no one rock. If the best macadam road be desired, that material should be selected which best meets the conditions of the particular road for which it is intended.

The movement for better country roads which has received such an impetus from the bicycle organizations is still felt, and is gaining force from the rapid introduction of horseless vehicles. To this demand, which comes in a large measure

  1. By Logan Waller Page, expert in charge of Road Material Laboratory, Division of Chemistry.