SPILLWAYS FOR RESERVOIRS AND CANALS. 
21 
1, Plate XII, and the arrangement of piezometer tubes and gage 
board in figure 2, Plate XII. A diagram of the testing laboratory 
and the setting of the siphons on the crest is shown in figure 1. 
Plate XIII. 
The Fort Collins models were larger than those at Throop College 
and were designed as a miniature of the Phoenix siphon shown in 
figure 8 and hinged to permit of changing the shape of the outlet leg. 
The tests were conducted to ascertain : 
Fig. 7. — Outline section of type of siphon spillway built by Gregotti in Italy. Note 
submerged intake lip and surface air control intended for use where floating trash or 
ice interferes with operation. 
(a) The theoretical and actual loss of head in the various parts. 
(h) The effects of various shapes of parts upon head loss in that 
part and upon the general efficiency. 
(c) The total efficiency of the structure and to determine a value 
for k in the formula Q = kAV 2 gH for different shapes. 
(d) The relation between the depth of submergence of the dis- 
charge lip and the depth of water over the throat to bring the siphons 
into action under different conditions of air inlet. 
