CAPILLARY MOVEMENT OF SOIL MOISTURE. 
11 
tank can be determined after the lid is placed in position. Around 
the outside and at the top of the tank is soldered a galvanized iron 
channel, three-eighths inch wide and three-quarters inch in depth. 
This channel is to receive the edge of the cover to the tank, 
The lid of the tank is of material similar to the tank and has the 
outer edge turned down three-quarters of an inch all the way around 
to fit into the channel on the tank. Passing through the lid and 
Fig. 1.- — Isometric view of open flume connected by wick to supply tank. 
soldered to it is the ell. Into the lid is fitted a f-inch tube through 
which water ma} T be added to the tank. To support the weight of 
the ell and to stiffen the lid, two galvanized-iron channels are riveted 
to the underside of the lid, running crosswise of the tank. These 
channels are placed just outside the ell. 
THE ELL. 
The ell is, as the name implies, an elbow used to change the direc- 
tion of the soil column from the vertical. It extends 6 inches 
