[wxsig] Barometer calibration question

[Ted11]

Hey everyone, 

I'm a bit confused with one of the steps in the barometer calibration
routine for the X1W-1, hoping someone can clarify. The instructions state:

"When you are finished with this step, water should be even with the tops of
both tubes and there should be no bubbles in the water. The last point is
very important."

Okay, got it - tubing should be completely full of water.  However, the
steps after this seem to rely on only the middle section of tubing being
full of water, while the ends are not; put another way, there is an air
"gap" between the water and the transducer.  This setup makes more sense to
me.  Can someone confirm?  Thanks for your help. 

Ted
K5KZ