Question

If you wanted to make a barometer that had a column of liquid about 6ft tall what would the density of the liquid have to be? 1meter=3.28ft 1in=2.54cm Density Hg=13.6g/ml 1atm=760torr

Answer 1

I have used this.
density x 9.8 x height(m) = 101.325 kPa
So if height is 6 ft (1829 mm) density is about 5.6 or so. Check that out.
Here is a good site.
http://hyperphysics.phy-astr.gsu.edu/hbase/pflu.html'\

But don't stop there. Click on the manometer link at the bottom and on pressure calculation link and this site will do all of the calculating for you.