to compression. In 1893 the Massachusetts Highway Commission established a laboratory at Harvard University for testing road materials. The French abrasion test was adopted, and tests for determining the cementing power and toughness of rock were added. Since then similar laboratories have been established at Johns Hopkins University, Columbia University, Wisconsin Geological Survey, Cornell University, and the University of California.
The Department of Agriculture has now established a road-material laboratory in the Division of Chemistry, where any person residing in the United States may have road materials tested free by applying for instructions to the Office of Public Road Inquiries. The laboratory is equipped with the apparatus necessary for carrying on such work, and the Department intends to carry on general investigations on roads. Part of the general plan will be to make tests on actual roads for the purpose of comparing the results with those obtained in the laboratory.
Besides testing road materials for the public, blank forms for recording traffic
