12 



The narrow ditch shown on the shde (fig. 3) will drain the 

 pools for about 100 feet on each side of it, (provided the level of 

 the water in the ditch be kept low enough to cause the water to 

 seep through the sod. The meadow surface throughout a large 

 part of New Jersey is enough above sea level to accomplish this 

 when the ditches are connected directly to tidewater. But in 

 Bergen, Hudson, Essex and Union Counties there are some large 

 areas too low to be drained effectively in this way. To keep down 

 the water level in these ditches the tide-gate was introduced. 



TIDE GATE . 



Fig. 4. — Diagram of a tide-gate. 



This diagram shows how it works. When the tide is low the 

 water in the ditches may flow out, but when the tide rises the 

 gate closes and does not open again until the next low tide. 



To keep the high tide from crossing the meadow surface a 

 dike is used, as is shown by the diagram. 



This shows a tide-gate, the photograph (fig. 5) being taken 

 approximately at low water. The dike is shown crossing the 

 sluiceway and the ditch. 



This is another view of a dike (fig. 6). I presurrie that a num- 

 ber of people here who have been watching these illustrations are 



