simple, it's not banged around, and you have the "super spring" as an extra stable reference. the main company closed (frankly, the owner was apparently doing some insurance fraud, and the company was never intended to be as successful as it became, we were making money and he shut it down! lots of resentment all around), i did work for the spin off for a time but my health got bad. they were working on an instrument to measure the gravity gradient (more sensitive to things close to the surface, and potentially not needing a super spring and more tolerant of vibration) but i don't know how far they got. the spin off has since been sold to a geo-tech company and only the chief scientist and one ee are still with them as far as i know. Tim Niebaur is the name to search for if you are interested, the original company was "Axis instruments", the spin off was "micro-g solutions". at one time the original company had a little over 20 employees, including 3 machinist, 3 M.E's etc. Dave VanHorn wrote: > > At 01:00 PM 10/17/2004, Jan-Erik Soderholm wrote: > > >Dave VanHorn wrote : > > > > > You can't discern between acceleration and > > > gravity, right? > > > >Actualy, gravity = acceleration. > > That's what was bothering me. > How do you measure gravity, in a portable instrument, when it's being > bumped and banged around? ------- -- President George W. Bush, Vice President Richard B. Cheney, Secretary of Defense Donald H. Rumsfeld, and Attorney General John D. Ashcroft have committed violations and subversions of the Constitution of the United States of America. They should be charged with high treason and as leaders deserve the highest penalty. If there is no rule of law there can be no civilization. _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist