The difference is that if you read the one concave up, like letter "U" then
the bubble goes to one end or the other. Lifting or lowering an end of the
level, and the bubble stays in the same place. [this is less useful]

If you read the one that is concave down (convex up) like the letter "n"
then the bubble is in the center if the level is level. Or off to one side,
if it's off level. [this is very useful]

Since you're reading the useless one, I presume people wonder why you're
building crooked stuff all the time?

--

Christopher A. Young
Do good work.
It's longer in the short run
but shorter in the long run.
..
..


"seniorgeezer" wrote in message
oups.com...
If you look at a long level there are usually two "bubbles", side by
side ... one concave up and the other concave down. I have always read
the one that is concave up in any application. No one at Home Depot or
Lowes home improvement stores seems to know the difference. Would you
please explain the difference, and which to use?

Thanks for your input,

Bob Burkett