18 feet in width, the cost of the road was 5.75 cents per square yard, or at the rate of $607.20 per mile. The total cost of the road to the community was $207. The cost of labor on this work was $1.50 per 10-hour day; foreman, $3.50 per day; while the teams were furnished free, with drivers, by the neighboring farmers. The work comprised 3,600 square yards.

EARTH AND SAND-CLAY ROAD.

MILFORD, DEL.-Work on the Milford Road, running northwest toward Frederica, was begun on July 28, 1910, and completed on August 19, 1910. The road runs through level country and the soil was partly sand and partly clay. The work consisted in grading 6,600 feet, 30 feet wide, and surfacing with sand-clay mixture, 30 feet wide, for 6,600 feet and 12 feet wide for an additional 1,400 feet. The 12-foot surfacing was finished with 9-foot shoulders. The construction thus required the treatment of two sections. The first section was rounded up with a grader machine and traction engine, taking the earth from the ditches. On the second section a sand-clay road was built as follows: Clay was placed upon the old roadbed 8 inches thick and upon this was laid a layer of sand 3 inches thick. After mixing the whole, 4 inches more of sand were added and mixed in by means of a spring-tooth harrow. The sand and clay were obtained from pits and hauled an average of 2 miles by teams at a cost of 46.3 cents per cubic yard. Spreading this material cost 4.2 cents per cubic yard and loading it cost 12 cents per cubic yard. Both sections followed the profile of the old road. The crown of the finished surface was made three-fourths inch to the foot. The total amount of clay and sand hauled from the pits was 486.5 cubic yards. The total amount graded up from the sides was 1,941 cubic yards, and this part of the work cost $70.63. Other items of cost were: Dragging the entire road, $12.48; cutting away weeds, $10.25; excavation other than by grader, $35.72; incidentals, $16.20; and labor for surveying, $22.55. The total cost of the road to the community was $472.78. The rate per square yard for the first section was 0.46 cent; the same rate for the second section was 19.7 cents, or $83.54 per mile for the machine-graded section and $1,389 per mile for the sand-clay road. This cost is based upon labor at $1.25 for a 10-hour day and teams at $3 per day. The work comprised 2,200 square yards for the first section and 1,866 square yards for the second.

EARTH ROADS.

MARIANNA, ARK.-Work was commenced at Marianna on October 24, 1910, on 3,500 feet of the Moro Road, running west toward Moro, and was completed on January 18, 1911. Two thousand cubic yards of earth were moved by means of small tools, plows, slips, wagon, and a grader, at a cost of $581.25. A total of 3,300 feet of this road was finished 30 feet wide and 200 feet were finished with a width of from 20 to 12 feet. The binding quality of the soil was not the best, but the condition of the surface can be maintained by use of a drag and wide tires. Two corrugated-iron pipe culverts were required, the first of two 18-inch corrugated-iron pipes 20 feet long, and the second of two 24-inch corrugated-iron pipes 20 feet long. The total cost of these pipes was $100; the labor for placing them, $12.65; and the second culvert was finished with concrete end walls which cost $31. The county built a bridge over the Caves Hill Branch, which was let for a contract price of $242. The construction was concrete abutments with steel "I"-beams and 2-inch plank flooring. Other items of expense in this work were as follows: Livery and services of a roadman, $37; and the Alabama Road drainage ditch, $168, one-third of which was borne by the county of Lee and two-thirds by the property owners.

The total cost of this road to the community was, therefore, $1,171.90, which is at the rate of 10.2 cents per square yard or $1,802 per mile, computed on the basis of a 30-foot width. The labor on this road was done partly by prisoners, but the cost is figured on a basis of $1 per 8-hour day for the county work and $1.35 for the city work. The corresponding cost of teams was $3 and $3.50 per day. The work comprised 11,444 square yards.

MISSOULA, MONT.-A mile of the Frenchtown Road, running west from the city, was graded and given a crown of 1 inch to the foot. The work was commenced on July 6, 1910, and was finished on July 9, 1910. This work was for the purpose of demonstrating the correct method of obtaining the shape of an earth road running through level prairie land with adjacent rolling country. The road was graded to a width of 30 feet, and 1,175 cubic yards of sandy loam

were excavated. The maximum grade of 8 per cent was about 50 feet in length and was reduced to 4.5 per cent. The work was done with a grader, plows, and slips, with a maximum haul of 200 feet. The cost was 7.4 cents per cubic yard or 0.5 cent per square yard. The total cost was, therefore, $87 for the mile completed. The work comprised 17,600 square yards.

CENTRAL CITY, NEBR.-A mile of road at Central City, running north toward Fullerton, was begun on August 19, 1910, and completed on September 7, 1910. Three thousand one hundred and eight cubic yards of material were excavated. The local authorities furnished for this work one elevating road grader, one blade grader, two Fresno scrapers, three slip scrapers, one turning plow, one spike-tooth harrow, and one 3-ton concrete roller, besides small tools and dump wagons. The grade was reduced from 6 to 2.5 per cent and the excavation cost 12.34 cents per cubic yard. The graded road was 36 feet wide throughout, with a finished wearing surface of 20 feet. One reinforced concrete box culvert, 2 feet by 2 feet by 24 feet, was built. The items of the concrete work were as follows: Cement, $16.65; sand, $5; lumber for forms, $13.35; broken stone, $5.25; steel rods and nails, $6.60; hauling the material, $5.50; and labor, $29; making a total of $81.35. An additional length of 15 feet of 15-inch metal corrugated pipe was placed, at a total cost of $18.75. The cost of rolling the road was $30.90, and the finished surface was given a crown of three-fourths inch to the foot.

Based on a labor cost of $2 a day for nine hours, and teams at $4 per day, the total cost of this road to the community was $554.05, which is at the rate of 4.72 cents per square yard, or $554 per mile, inclusive of culverts. The work comprised 11,733 square yards.

CORDELL, OKLA.-This work was on what is known as the Intercounty State Road, running east, and was 24,000 feet in length. The work was begun on July 16, 1910, and was finished on February 13, 1911. A total of 2,000 cubic yards of rock and 33,803 cubic yards of earth was moved, at an average price per cubic yard of 17.3 cents, making a total cost of $6,200. The shaping cost 0.8 cent per square yard, which, for 24,000 square yards, made a total cost of $200.50. The grade was reduced from 15 to 6.6 per cent, and the maximum cut on this work was 15 feet and the maximum fill 20 feet. The following culverts were required: Five concrete arches 24 by 2 feet, two concrete arches 4 by 31 feet, and two concrete twin arches having a total span of 23.5 feet each. It was also necessary to construct one set of concrete abutments 20 feet high by 22 feet long, concrete wing walls 20 feet high by 11 feet long, and two 24-inch corrugated-iron pipe culverts. The culverts required 750 barrels of cement, costing $2.60 per barrel, or $1,950. The gravel for the concrete was obtained from the river bed at a cost of 5.98 cents per cubic yard. A total of 483.6 cubic yards of concrete was used. A concrete mixer and road grader were available for the work.

The total cost of the road was $12,016.20, which is at the rate of 17.31 cents per square yard. or $2,641 per mile. Prison labor cost 25 cents and county teams 60 cents per nine-hour day. The work comprised 69,333 square yords, or 4.55 miles.

CORDELL, OKLA.-This was a part of the Intercounty State Road running west from Cordell toward Dill. Work was begun on March 3, 1911, and was finished on April 17, 1911. A total of 6,200 feet was graded, requiring 15,355 cubic yards of excavation at a cost of 15.3 cents per cubic yard, or $2,346.35 in all. Seven hundred and sixty cubic yards of rock also were excavated, at a cost of 51.4 cents per cubic yard, making a total cost of $390.85. Three pipe culverts were built at a cost of $206.60. One 4-foot by 4-foot by 26-foot wood culvert and two wooden bridges of 18 feet and 16 feet span, respectively, were also constructed, the culvert at a cost of $14 and the two bridges at a cost of $175.25. Other miscellaneous items of expense on this work, including moving the prison camp, etc., amounted to $271.50.

The total cost of the road to the community was $3,434.55, which is at the rate of 18.2 cents per square yard, or $2,910 per mile. Prison labor cost 25 cents, and county teams 60 cents per day of 9 hours. The work comprised 18,890 square yards.

DEMONSTRATION WORK.

MEDFORD, OREG.-This work was done under the auspices of the Crater Lake Highway Commission, representing the Medford Commercial Club. At the request of this Commission an engineer was sent to make a survey of the pro

posed road and to prepare specifications for the work, which was begun under his supervision. One-half of the funds for surveys and construction was raised by subscription, and the remainder supplied from public revenues by the county commissioners. After the work was well under way, the county commissioners appointed a county road engineer, who took charge of the work. The following report, therefore, includes only the work done under the supervision of this office.

The work was done on a county road leading from Medford, Oreg., to Crater Lake National Park, and extended over what is locally known as Flounce rock relocation. By this relocation 100 feet of adverse grade was eliminated and one-half mile of grade ranging from 12 per cent to 33 per cent was replaced by a roadway with a grade varying from 0.5 to 4 per cent, without appreciable increase in the distance.

The country is mountainous and the slopes of the hillsides are steep, ranging in this section from 8 to 35 degrees. All the excavation, with the exception of two short cuts, was open hillside work. This, together with the short haul, reduced the work to what could be done with pick, shovel, and scraper. Push cars were used where economical. The work was done by contract at the following prices: Earth excavation, 18 cents per cubic yard; hardpan, 48 cents per cubic yard; loose rock, 52 cents per cubic yard; solid rock, 98 cents per cubic yard; clearing, $750; grubbing, $2,250; and hand-laid riprap, $1.50 per square yard. All work not covered by these items was done by force account. The free haul limit was 300 feet, and the overhaul was 1 cent per cubic yard for each 100 feet additional. The cost of the work done under the supervision of this office was $7,512.09, and consisted in the removal of 2,106 cubic yards of earth, 895 cubic yards of hardpan, 2,139 cubic yards of loose rock, and 3,196 cubic yards of solid rock. In addition, a portion of both clearing and grubbing had been completed, 242.2 square yards of riprap laid, and cross drains placed by force account. Labor was paid $2.50 per day; foreman, $3.50; and teams, $30 per month and maintenance. Four thousand five hundred feet of work had been opened up, and 1,600 feet brought to an approximate grade. No surfacing whatever had been done.

The width of the road varied from 18 to 23 feet and all blind curves were widened to insure safety to traffic. Corrugated-iron culverts were used, while head and tail walls were made of hand-laid riprap. The work was done between October 6, 1910, and March 31, 1911, during which 36 days were lost because of rain and inclement weather.

VALLEY CITY, N. DAK.-This was an earth road built along section lines to replace the original cross-country trail. The work consisted in stripping the sod, removing it, and grading and compacting the roadway. The work was done with wheel and slip scrapers and a road grader and was completed with a gasoline traction engine. Approximately 800 feet of roadway had been constructed when the work was turned over to the county authorities for completion.

UNFINISHED ROADS.

On May 18, 1911, the construction of a sand-clay road was begun at Demopolis, Ala. As this work was not completed until July 20, 1911, it will be referred to in the next annual report.

On June 17, 1911, the construction of a bituminous-macadam road at Silver Springs, Md., was started. This work was completed on September 5, 1911. A report on this project will be given in the next annual report.

EXPERIMENTAL WORK AT ITHACA, N. Y.

The experimental work at Ithaca, N. Y., described in the last annual report, had then covered 15 experiments. Since that time the number of experiments has been extended to 24, and the work is still progressing. A detailed account of these 9 additional experiments will be found in Circular No. 94, issued by this office. The experiments were carried out for the purpose of ascertaining the relative value, under practically uniform conditions, of different road binders applied by different methods. The roads selected for these experiments were East Avenue and South Avenue, on the grounds of Cornell University, and adjoined the roads formerly treated. Both of these roads are subjected to heavy traffic during the winter, and in the summer to considerable automobile travel and light draying.

The work was begun on September 12, 1910, and continued until November 10, 1910, when bad weather prevented its completion. It was again taken up on July 10, 1911, and the field work was completed on August 12, 1911, and will be described in detail at a later time. Of the nine experiments mentioned above, one was with refined water-gas tar, one with asphalt block, five with oil asphalt, one with a refined asphaltic preparation, and one with a semisolid refined semiasphaltic oil. In these experiments various methods of applying the bituminous binder were tried, including the penetration and mixing methods and the prepared-filler method. The sections treated were rather short, and most of them did not exceed 300 feet, which made the unit costs rather high. The cost per square yard for the wearing surface varied from 82.18 cents to 49.73 cents. The highest cost was for a section 300 feet in length of oil asphalt, laid by the mixing method, and the lowest cost was for an oil-asphalt section 300 feet long, treated by the penetration method.

INSPECTION OF OBJECT-LESSON ROADS.

During the past fiscal year inspections were made of nine objectlesson roads previously built under the direction of this office. These were located at the following places: Dodge City, Kans.; Palatka, Fla.; Bowling Green, Ky.; Newton, Mass.; Williamston, N. C.; Carnegie, Okla.; Greenville, S. C.; Knoxville, Tenn.; and Mexia, Tex.

All of these roads were found in good condition, some in excellent condition. The road built at Bowling Green, Ky., with rock asphalt presents an especially satisfactory appearance and is significant as a result of construction with locally obtained rock asphalt.

At Greenville, S. C., the contrasting appearance of portions of the same macadam road, built in 1909 and 1910, was striking. The portion finished with bitumen was in excellent shape, whereas the waterbound macadam showed a wear of from 1 to 2 inches.

HIGHWAY BRIDGES AND CULVERTS.

In the report of this office for 1910 mention was made of the need for better highway bridges and culverts. The need still exists and is becoming more apparent each year.

During the year a division of bridge and culvert engineering was established in this office, and an experienced bridge engineer was employed for the purpose of collecting and preparing useful data on this subject and preparing it suitably for distribution. Bulletin No. 39, entitled "Highway Bridges and Culverts," was issued, and other bulletins dealing more in detail with the different types of bridges and culverts, are in preparation.

Upon proper application a bridge engineer will be sent, if deemed practicable, to make inspection, survey, and estimate for proposed bridges and culverts, to prepare plans, and to superintend the erection of such structures. It is intended, however, that this assistance shall be limited to object-lesson work.

Under the direction of the bridge engineer of the office, there were built at Bennettsville, S. C., between November 12, 1910, and December 16, 1910, three reinforced concrete culverts at a cost of $332.50 for labor alone. Culvert No. 1 was a 16-foot span, 30 feet wide to the outer side of the parapets, with side walls 4 feet high and the cover of the steel I-beam type incased in concrete. Culvert No. 2 was a 7-foot span, 30 feet wide to the outer side of the parapets with side walls 5 feet high and the cover of reinforced concrete slab. Culvert 23165°- -AGR 1911-47

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 slab. 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, $14.50; 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 practically 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 engineer student in this office has continued along the same lines as heretofore. 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 promoted 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-preservatives, sand, clay, brick, slag, cement, coke, concrete, and concrete waterproofing materials.