Hi mariog

I am a European. We look at things differently. We have tended to throw off the shackles that have - in our opinion - passed their shelf life.

Now, what do you see as the units of density in your stated equation?

The metric system was built from the ground up during Napoleon's time. It did not depend on the human foot or the length of the first joint of the thumb or the cubit. Mechanical units were constructed from the second, the metre and the kilogramme. Force, pressure, heat transfer etc., were derived from the primary units. The unit of pressure was Newtons(derived unit) = kg(primary unit) multiplied by metres(primary unit) divided by seconds squared(primary unit)

Thus to me (a European) pressure is expressed strictly in force/area units, though it be derived from hydraulic pressure.

In the final analysis, folk will continue with a system in which they are comfortable. I cite as the primary example the resistance of America to adopt what other countries have been using for years. They just don't like it.