On Thu, 20 Jan 2000 16:35:43 EST ChrisAtUpw@....... writes:
>Dear Mr.Leiper,
>
>    Thanks for the quick reply. I thought that it might be something 
>like this, for the last time that I looked at the price of a large piece
of 
>engineering quality polished granite, the cost was $ thousands, not 
>hundreds.
  
big snip

>I was looking at an old 4 lb glass bottling jar (Kilner) the other 
>day and wondered if a mini S-G seis. could be fitted inside....
>
>    Regards Chris Chapman 
>
Interesting. Why not use a Klein bottle to achieve infinite period? And
if you recorded on a Mobius strip, you would only
need to find a pen with a bottomless inkwell...

Actually there is no problem. Having tested the insane route I am certain
the effect I am seeing (and saw with the first
instrument to a lesser degree) is in fact seasonal tilt due to the weight
of the house and/or the beech tree. The tree is
known to induce artifact in gale force winds, and I am sure it weighs
thousands more when foliated. What I have now
requires slight centering only twice yearly, which is pretty good for an
instrument of such period, and what I have concluded
(and independently has been confirmed in ST's recent post about the LP
instruments used in global system) is that periods
in excess of 15 to 20 seconds are not worth the effort...it is much
simpler to use force balance/feedback techniques and get
all the period you want. (or perhaps the Klein bottle...get to work on
that one)

My principle reason for experimentation is to learn what is important and
try to come up with something more realistic
for the weekend mechanic accountant who wants to do something with his
kid. Most of the discussion and experimentation
here is an order of magnitude (or two) above what I have in mind. Nobody
uses a pair of tin cans and a string anymore...they
just go to radio shack and buy some walkie talkies. What happened to
train sets?

For instance, if we cut the grass around that old '74 Impala wagon on
blocks and cram it with all the half empty cans of 
hardened blacktop sealant, that bag of setting concrete you never used to
plant the new mailbox, the old bikes and other crap
from the garage...

Then remove the wheels and set the brake drums/disks directly onto steel
plates...Attach a twenty foot cantilevered 
and balanced truss beam (made of 2X2) to the trailer hitch with a magic
marker attached to the other end and the fulcrum 
about a foot from the hitch end. Modify the treadmill you got for your
wife (never used) by replacing the tread with deli paper
(preferably also unused) and change the gearing or motor to achieve
desired recording speed. Point the car NS or EW and
away you go...no longer the neighborhood eyesore, the ingenious new
application makes you the neighborhood madman.
Instead of carving out "S" turns it traces out "S" waves...

Speaking of madmen, drill down from the following link to "tim working
out",  the "antenna farm" and "this" for a good laugh.

Note the innovative use of the fridge... 

http://members.localnet.com/~wa1sov/meet_the_amers/schoolbus.html

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