In (sci.engr.surveying), Stephen wrote:

As you can see a water level is the most popular low price solution. A few
years ago I showed guy that was putting new siding on his house how to use a
water level. He thought I was a genius for coming up with such a good
method but I had to confess that it's an old trick probably a hundred years
or more old. In old books I have seen them made by putting glass tubes in
the end of an old rubber hose. The only real advantage of using a laser or
transit is ease of use A pole barn or most residential building don't need
any more accuracy than you can get from a water level

s/hundred/three thousand or more/

The Egyptians used water levels in laying out and constructing the
pyramids, according to some fairly recent articles in archaeological
journals.

--
Mike Andrews

Tired old sysadmin