786 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



characteristics of such materials to meet local conditions. These 

 materials arc sold under trade names, and as a rule carry no valid 

 guaranty of quality. Specifications for such mateiials are there- 

 fore needed for the protection of the pu])lic, and this phase of the 

 work will be <j;iven continued attention by the Ofhce. Some manu- 

 facturers have already followed the work of the Olhce alon^ this line, 

 and are either manufacturing materials in accordance with specifi- 

 cations of the Oflice or stand ready to do so upon request. 



Among the special investigations of bituminous road materials 

 carried on by tne laboratory may be mentioned improvements in 

 methods of analysis, the efi'ect of various methods of distillation upon 

 the physical and chemical properties of tars, and the development of 

 a test for determining the binding value of bitumens. The Office 

 is cooperating in these matters with various technical societies, such 

 as the Permanent International Association of Road Congresses, the 

 American Society for Testing Materials, and the American Society 

 of Civil Engineers. Among the papers which have been published 

 along these lines during the past year may be mentioned Circular 

 No. 92, United States Office or Public Roads, concerning the physical 

 and chemical characteristics of bituminous road materials, and the 

 determination of soluble bitumens. 



INSTRUCTION IN HIGHWAY ENGINEERING. 



The plan of appointing graduates of the leading engineering insti- 

 tutions to the position of civil engineer student in this Office has 

 been continued throughout the fiscal year along the lines previously 

 followed. An examination was held March 9-10, 1910, under the 

 auspices of the Civil Service Commission, and an eligible register 

 established from which seven engineer students were appointed dur- 

 ing the fiscal year 1910. 



As evidence of the demand for competent highway engineers 

 throughout the countr}^, and the extent to which the engineers of this 

 Office are being utilized to meet this demand, it may be stated that 

 during the past fiscal year eight engineers have resigned from the 

 service to take up road work in various parts of the country. 



LECTURES, ADDRESSES, AND PAPERS. 



The w^ork of the Office under this project, comprising in all 523 

 lectures, addresses, and papers, was distributed over a wide range of 

 territory, embracing the States of Alabama, Arkansas, Delaware, 

 Florida, Georgia, Idaho, Illinois, Indiana, Kansas, Kentucky, 

 Louisiana, Marjdand, Michigan, Mississippi, Missouri, Nebraska, 

 New York, North Carolina, North Dakota, Ohio, Oregon, Penns^d- 

 vania, South Carolina, Tennessee, Texas, Utah, Virginia, Washing- 

 ton, and West Virginia, and the District of Columbia. A large propor- 

 tion of the addresses was given at farmers' meetings in small towns 

 and villages, but the work included a great many lectures and papers 

 before scientific organizations and conventions of road builders and 

 road officials. In view of the fact that the widespread dissemination 

 of information is essential to the betterment of road conditions, it is 

 believed that giving lectures of a practical character is productive of 

 excellent results. 



