112 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



nil various road matters. Twenty-three States and the District of 

 Cohimbia have thus enjoyed the benefits of expert advice by higli- 

 way engineers. Inspection of the State highways of New Hamp- 

 shire forms the subject of a report issued as Bulletin No. 42, Office 

 of Public Roads. The report treats of the existing conditions and 

 materials, forms of construction, and special problems involved in 

 New Hampshire highways. 



INSTRUCTION IN IIIGIIAVAY ENGINEERING. 



Graduates in civil engineering from engineering institutions through- 

 out the country may become eligible for appointment to the position 

 of engineer student after passing the required examinations of the 

 United States Civil Service Commission. Examinations were held 

 on March 13 and 14, 1912, and from the register established 10 

 appointments were made. The students who come to the office in 

 this way receive a thorough training in all parts of highway work 

 in the field and in the laboratory. At the end of their first year 

 many prove worthy and are either promoted to serve in the office 

 or to suitable positions in count}'^ or State work. At the close of 

 the second year junior highway engineers are eligible to promotion 

 as high w^ ay engineer and may ultimately attain the grade of senior 

 highway engineer. 



PHYSICAL LABORATORY. 



The laboratory for the testing of road-building stone has con- 

 tinued to be of large service. Samples have been received from 37 

 States and Territories, as well as from Canada, Porto Rico, and 

 Wales. Research work in the physical laboratory has progressed 

 satisfactorily^ and includes the testing of a large number of arch 

 culverts in full-size sections. Studies on the subject of expansion 

 and contraction of concrete while setting have proved of interest 

 and results of value are anticipated when the work has further 

 progressed. Observations have continued on the behavior of oil- 

 mixed concrete, and a bulletin showing the progress of investiga- 

 tions has been issued. 



During the 3'ear various papers were presented by members of the 

 testing laboratory force on results of research work. A bulletin 

 has been issued on the methods and results of physical testing of 

 road materials. 



CHEMICAL LABORATORY. 



With the increasing use of bituminous materials in modern road 

 construction, the services of the chemical laboratory have become 

 very important. During the year 198 samples of oils, asphalts, 

 tars, and other bituminous materials were received and tested for 



