738 ANNUAL REPORTS OF DEPARTMENT OF AGRTCITLTTJRE. 



No. 3 was a 2-foot span, 30 feet wide to the outer side of the parapets, 

 with side walls 2 feet high and the cover a reinforced concrete shib. 

 Screened gravel was used in all the concrete for the aggregate. The 

 following distribution of labor cost is made: Excavation, $38.50; 

 screening the gravel, $31.50; hauling the gravel, sand, and cement, 

 $184.50; mixing the concrete, $44.50; and building and removing the 

 forms, $33.50. Convict labor was used on this work and was charged 

 at 50 cents per man per day of eight or nine hours, which was prac- 

 tically the cost of boarding and caring for the convicts. County teams 

 were used and charged at $1.50 per day per team. 



INSTRUCTION IN HIGHWAY ENGINEERING. 



The plan of appointing graduates in civil engineering from the 

 leading engineering institutions in the country to the position of en- 

 gineer student in this office has continued along the same lines as here- 

 tofore. An examination was held on March 8 and 9, 1910, under the 

 supervision of the Civil Service Commission, and an eligible register 

 was established from which seven engineer students were appointed 

 during the fiscal year. 



The demand for competent highway engineers is increasing 

 throughout the country from year to year. During the fiscal year 

 1911, 12 highway engineers resigned their positions in this office to 

 accept service in connection with road work in various parts of the 

 country. Of this number 8 were junior highway engineers, 3 were 

 engineer students^ and 1 occupied the position of highway engineer. 



During the first year that engineer students are connected with the 

 office, they are given a thorough training in all branches of highway 

 work, both in the field and in the laboratories, while at the same 

 time their services are fully utilized by the office in laboratory and 

 field work. At the end of the first year, if the students prove worthy 

 and it is found that the needs of the service justify it, they are pro- 

 moted to the position of junior highway engineer. At the close of the 

 second year they are eligible for further promotion to the grade of 

 highway engineer, and ultimately to the position of senior highway 

 engineer. 



This project has given excellent results, and the engineers after a 

 few years' training in the office are in great demand for State and 

 county work. The practice of permitting these engineers to resign 

 is detrimental in one sense to the service, in that the office is constantly 

 losing some of its best men, but the benefits derived by the various 

 States and counties through the distribution of trained men to all 

 sections of the country are so great as to be a vindication of the 

 wisdom of this project. 



PHYSICAL AND CHEMICAL INVESTIGATIONS OF ROAD MATERIALS. 



During the fiscal year 1911 there were received by the physical, 

 chemical, and petrographic laboratories a total of 685 samples of 

 road materials to be tested. These included rocks and gravel for 

 road-building, oils, tars, and other dust-preventives and road-pre- 

 servatives, sand, clay, brick, slag, cement, coke, concrete, and concrete 

 waterproofing materials. 



