Re: The new issue of NCPTT Notes, which has a nice little article
"Evaluating Historic Masonry with the Pendulum Hammer."

Michael Schuller of Atkinson-Noland & Associates in Boulder, Colorado
(303-444-3620) in association with Wayne Ruth of Masonry Solutions in Hunt
Valley, Maryland (410-683-0177) have a pretty impressive "road show"
presentation regarding non-destructive testing and grout injection for
those interested enough in assembling a small audience.  They can even
challenge you to pick up a trowel and lay brick yourself, right in the
convenience of your conference room.  The pendulum hammer is only one of a
few dozen tests they describe.  You should see their pulse velocity
procedures, tomographic imaging, impact echo and use of "flat jacks",
little pancake jacks they insert into mortar joints to test sheer and
compressive strength of masonry walls without taking a single brick out of
place.  Tell 'em Jim Rhodes sent you.