20 



BULLETIN 831, U. S. DEPARTMENT OF AGRICULTURE. 



reasonably well founded. The Throop College experiments were 

 conducted by Mr. E. X. Allen, a student of the institute, as a basis for 

 a thesis, and were directed by Professors Ford and Thomas, also of 

 the college, and Mr. Louis C. Hill, of Los Angeles. The Fort Collins 

 tests were conducted by the writer, at the cooperative hydraulic 

 laboratory of the United States Bureau of Public Roads and the 

 Colorado Experiment Station and, of course, all of these tests 

 must be given only such weight as would result from a laboratory 

 rather than a working model. They will tend to encourage research 



Fig. 0. — Cross-section outline of Lagolunga Reservoir siphon spillway. This is a typical 

 example of the siphons installed in Europe where there is no trash or floating ice to 

 clog the throat. 



to develop the proper data from tests in a full-size structure, and 

 suggest the study of such points as were not touched upon in the lab- 

 oratory tests and will also stand as a guide to the finding of causes 

 for the peculiar behavior in the smaller models. Great care was 

 exercised in the design of the model siphons to obtain theoretically 

 correct proportions for the intake, throat, outlet chamber, and outlet 

 opening, both with and without the lower seal. 



In the models for the Throop College experiments corrections 

 were made for the friction coefficient of the materials as shown in 

 standard tables. The outline of one of the models is shown in figure 



