BJ Conner wrote:
It could used for a lot of things.

The "measure the height of a building using a barometer" anecdote comes
to mind for some reason. g

Those of us that went to
engineering school before PCs had to take such things as drafting ( or
engineering drawing as it was called).

I took a Thermodynamics class using a slide rule. Nothing scares me
now. I actually spotted a Pickett slide rule in an antiques store a
few weeks ago. My youngest offspring was surprised not only that I
knew what it was, but that I knew how to use it (and seemed to take
pleasure in that talent).

The gazortenblotch in the picture looks like a for a special use or
process. The use or the process???

My rudimentary French suggests to me its function is some sort of
inclinometer (meters of length per 25 m/ht?). Beyond that, I'm
stumped.

Joe F.