Ted,

Yes, the pictures were very interesting.  I'll second your thanks, to Ed.

Back in those days, the amplification of seismic motion was generally 
done with mechanical linkages operating physical pens.  A large mass 
was necessary so that the linkage forces didn't greatly retard its motion.

Today with electronic motion sensing and amplification, and using 
very efficient pivots, a hundred grams or so is plenty.  And in fact, 
with feedback instruments, making the mass too large can create problems.

Regards,
Brett

At 10:18 AM 5/27/2010, you wrote:
>Ed,  Thank you for these pictures, they are great.............One 
>question for the group.   What was the reasoning behind the very 
>large masses.   The use of large masses seems to be repeated.
>Thanks, Ted
>----- Original Message -----
>From: Edward Ianni
>To: psn-l@..............
>Sent: Wednesday, May 26, 2010 5:55 AM
>Subject: Seismos
>
>There are some interesting pictures of seismographs at this site.  Ed.
>
> 
>http://sismordia.blogspot.com/search/label/Sunday%20seismometer
>
>


__________________________________________________________

Public Seismic Network Mailing List (PSN-L)