240 



SEASON 1877-78. 



slid, and, when filled between with clay, the water is completely 

 stopped. The leg is cut by two pairs of grooves precisely similar 

 to those in the straight of the trough. If these are filled, the water 

 flows straight ; if the grooves in the straight are closed also, the 

 water would dam back in the pipe. This invariably makes a mess 

 of the ground at the junction of the trough with the sanitary pipe, 



FIG. 164 scale - 



FIG. 165 scale fa. 



FIG. 166 scale 



and care should be exercised when closing the leg to see that the 

 straight is clear, and vice versa. The trough was fitted at its 

 lower end into the screen-box, which was made on the same principle 

 as the screen-boxes already described at Howietoun, and has a very 

 arduous task to perform, the sand, owing to the position of the 

 leaf-screen, collecting in it in large qviantities. In fact, the box 



