374 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



trie Concentrated Loading," Journal of Agricultural Research ; " The 

 Cause of Cracks in Concrete Pavements," American Association for 

 the Advancement of Science ; " The Influences of Total Width upon 

 the Effective Width of Concrete Slabs," American Concrete Insti- 

 tute ; " The Flow of Concrete," American Concrete Institute. 



The following investigations are in progress: Tests of reinforced 

 concrete slabs; tests of concrete beams containing various coarse 

 aggregates ; wear measurements of experimental concrete roads ; the 

 flow of concrete having various unit stresses. In addition, it is 

 planned to conduct investigations along the following lines: Study 

 of concrete for its abrasive resistance; tests of reinfo-rced-concrete 

 floor beams ; effect of freezing on changes in length of concrete. 



ROAD AND BRIDGE FOUNDATION TESTS. 



A soil-pressure laboratory has been constructed and put in oper- 

 ation at Arlington Farm. A paper upon the " Distribution of Pres- 

 sure Through Earth Fills" was presented before the American So- 

 ciety for Testing Materials. An investigation has been started in co- 

 operation with the Miami conservancy clistrict upon pressures result- 

 ing from hydraulic fills, and special equipment lias been installed for 

 the necessary tests. The apparatus which was devised for measuring 

 the distribution of pressure through fills has been perfected so as to 

 make it thoroughly practical for both laboratory and field tests. In 

 addition to continuing the laboratory soil-pressure investigations it 

 is proposed to direct immediate attention to the measurement of 

 reaction distribution under concrete pavements and foundations. 



FARM-IRRIGATION INVESTIGATIONS. 

 UTILIZATION OF WATER IN IRRIGATION. 



Experiments to determine the best methods of using water in 

 irrigation have been carried on in cooperation with the following: 

 State of Arizona, in the Salt Eiver Valley ; State of California and 

 the California Agi-icultural Experiment Station, in Imperial and 

 Sacramento Valleys and at the Davis farm; Colorado Agricultural 

 Experiment Station, in the Cache la Poudre Valley ; Idaho Agricul- 

 tural Experiment Station, at Gooding, Idaho; and with local organ- 

 izations at Twin Falls, Idaho; Kansas Agricultural Experiment 

 Station, at Garden City; New Mexico Agricultural Experiment 

 Station, at State College; State engineer of Nevada, and the Uni- 

 versity of Nevada, in Lamoille Valley ; Oregon Agricultural Experi- 

 ment Station, at Paisley and Burns; Texas Board of Water Engi- 

 neers, at Mercedes and Laredo, Tex. ; Utah Agricultural Experiment 

 Station, at various points in Utah. The cooperative Avork in Ari- 

 zona, Idaho, and Oregon was terminated during the year. Bulle- 

 tins giving the results of cooperative work covering several years in 

 the Sacramento Valley, and at the Davis farm, and a bulletin on 

 rice irrigation in the Sacramento Valley were published by the 

 University of California. A report of the work in Oregon was 

 published by the Oregon Agricultural Experiment Station, and 

 reports of the work in the other States have been prepared. A field 

 laboratory for the study of evaporation from Avater and soil surfaces 



