64 



IRRIGATION. 



&quot; Fig. 28 is a longitudinal section, and fig. 29 a cross 

 section of the outlet drain, show the arrangement for 

 checking the flow of the siphon. A dam (i) which may 

 be of wood, brick, or any other suitable material, closes 

 the drain in front of the siphon to a hight a little above 

 its lower end. This is notched down at its top to a point 

 just below that of the end of the siphon, in such a way 

 that after the barrel is discharged, the siphon itself will 

 be emptied and will fill itself with air. This notch is too 

 small to accommodate any considerable flow of the pipe, 

 and the dam checks back the first water running, and 

 helps to bring the siphon into action, but after the flow 

 has all passed over, it lets the water behind the dam fall 



low enough to admit air to the 

 pipe. I do not know that any 

 thing further is necessary in the 

 way of practical directions, ex 

 cept to say that the siphon pipe 

 had better be attached to the 

 side of the barrel, outside and 

 in, by bits of tin tacked over it 

 so as to prevent it from being in- 



Fig. 28. OUTLET. Fig. 29. 



jured. Indeed, the whole siphon might be inside of the 

 barrel, its lower end passing out through a hole near the 

 bottom ; this arrangement entirely obviates the danger of 

 its becoming jammed, or the possibility of a trickling flow 

 through it being frozen until the accumulated ice would 

 quite close it.&quot; 



The danger of filling up the pipes with sediment would 

 prevent the application of this system to the use of mat 

 ter from cesspools or barnyard manure tanks. It would 

 not, however, prevent its use for the purpose of discharg 

 ing a cesspool through a pipe of sufficient diameter, 4 to 

 6 inches for instance, into a manure tank in the stable 

 yard, where it could be mingled with the liquid draining 

 from the stables. This manure tank would then form 



