On Thu, 12 Feb 2015 20:43:17 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Thu, 12 Feb 2015 08:43:21 -0500, "Jim Wilkins"
wrote:


They don't appear to have known about this carving of a construction
crane.
http://mv.vatican.va/3_EN/pages/x-Sc...Sala01_06.html
They showed a modern pulley block without giving that image as proof
that the Romans used them.

Wow, cranes, pile-drivers, and pulleys? They were further evolved
than I'd thought. Very cool.

In many ways we didn't advance past them until 1700 - 1800.

Their concrete formula still works to this day.

--
Silence is more musical than any song.
-- Christina Rossetti