In a message dated 7/13/01 6:21:42 AM Pacific Daylight Time, CapAAVSO@....... 
writes:


> Subj: Re: Lehman??
> Date: 7/13/01 6:21:42 AM Pacific Daylight Time
> From:    CapAAVSO@.......
> Sender:    psn-l-request@..............
> Reply-to: psn-l@..............
> To:    psn-l@..............
> 
> 
> 
> 
> In a message dated 7/13/01 2:50:44 AM GMT Daylight Time, ACole65464@....... 
> writes:
> 
> << I just scanned a small photograph out of an old catalog tilted 
> "Geophysics 
> & 
> Geomagnetism", published by the Science Museum. The photo matches closely 
> the 
> instrument that you described in words. I picked a the copy of the catalog 
> when I was visiting London 10-12 years ago. Go to the following Web page to 
> see the scanned image (370K jpeg):
> 
> http://hometown.aol.com/acole65464/SEISMOPICS.html >>
> 
> Thanks Allan,
> 
> Your very nice scanned image shows that it is a Lehman-type horizontal 
> seismometer. The boom apparently extends back to a pivot point out of the 
> picture with the mass supported by the turnbucle/cable going up at an 
> angle. 
> With the obviously very heavy mass stacked right up to the boom it would 
> act 
> like a Lehman seismometer. the photo shows two pins to restrain horizontal 
> movement of the boom which extends into the complicated mechanism Ted 
> describes. The mechanism looks like a system of compound levers that are a 
> mechanical amplifier. I would guess that the nearest pen is amplified the 
> least and records strong movement. What looks like two additional lever 
> systems for the farthest pen probably amplify its movement additionally to 
> show more detail in the seismogram. The pens and lever systems would 
> provide 
> drag that amounts to damping. Presumably the loop of paper runs for 24 
> hours 
> so time could be measured from the start where the time of start would be 
> marked on the paper loop. It is certainly an interesting mechanical device 
> that could record earthquakes. Its sensitivity would depend on the lever 
> system. The photograph shows what seems to be a carefully built and well 
> designed system of levers that provide mechanical amplification. I hope 
> Chris 
> Chapman, who is an engineer, will figure out the amplification factor when 
> he 
> visits the museum in a couple of months.
> 
> Best regards,
> Cap
> __________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email PSN-L-REQUEST@.............. with 
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
> 
> 
> ----------------------- Headers --------------------------------
> Return-Path: 
> Received: from  rly-zd05.mx.aol.com (rly-zd05.mail.aol.com [172.31.33.229]) 
> by air-zd05.mail.aol.com (v79.27) with ESMTP id MAILINZD55-0713092142; Fri, 
> 13 Jul 2001 09:21:42 -0400
> Received: from  sys5.webtronics.com (sys5.webtronics.com [216.100.224.130]) 
> by rly-zd05.mx.aol.com (v79.20) with ESMTP id MAILRELAYINZD56-0713092126; 
> Fri, 13 Jul 2001 09:21:26 -0400
> Received: from imo-r08.mx.aol.com (unverified [152.163.225.104]) by 
> sys5.webtronics.com
> (Rockliffe SMTPRA 4.5.4) with ESMTP id  
> for ;
> Fri, 13 Jul 2001 06:16:52 -0700
> Received: from CapAAVSO@.......
>     by imo-r08.mx.aol.com (mail_out_v31.7.) id x.d8.8f4e1ef (3968)
>     for ; Fri, 13 Jul 2001 09:15:38 -0400 (EDT)
> From: CapAAVSO@.......
> Message-ID: 
> Date: Fri, 13 Jul 2001 09:15:38 EDT
> Subject: Re: Lehman??
> To: psn-l@..............
> MIME-Version: 1.0
> Content-Type: text/plain; charset="US-ASCII"
> Content-Transfer-Encoding: 7bit
> X-Mailer: AOL 4.0 for Windows 95 sub 114
> Reply-To: psn-l@..............
> Sender: psn-l-request@..............
> 

who are you, why do you converse with someone else in my screen name?
In a message
 dated 7/13/01 6:21:42 AM Pacific Daylight Time, CapAAVSO@....... 

writes:





Subj: 
Re: Lehman??

Date: 7/13/01 6:21:42 AM Pacific Daylight Time

From:    CapAAVSO@.......

Sender:    psn-l-request@..............

Reply-to: psn-l@..............

To:    psn-l@..............









In a message dated 7/13/01 2:50:44 AM GMT Daylight Time, ACole65464@....... 

writes:



<< I just scanned a small photograph out of an old catalog tilted 

"Geophysics 

& 

Geomagnetism", published by the Science Museum. The photo matches closely 

the 

instrument that you described in words. I picked a the copy of the catalog 

when I was visiting London 10-12 years ago. Go to the following Web page to 

see the scanned image (370K jpeg):



http://hometown.aol.com/acole65464/SEISMOPICS.html >>



Thanks Allan,



Your very nice scanned image shows that it is a Lehman-type horizontal 

seismometer. The boom apparently extends back to a pivot point out of the 

picture with the mass supported by the turnbucle/cable going up at an 

angle. 

With the obviously very heavy mass stacked right up to the boom it would 

act 

like a Lehman seismometer. the photo shows two pins to restrain horizontal 

movement of the boom which extends into the complicated mechanism Ted 

describes. The mechanism looks like a system of compound levers that are a 

mechanical amplifier. I would guess that the nearest pen is amplified the 

least and records strong movement. What looks like two additional lever 

systems for the farthest pen probably amplify its movement additionally to 

show more detail in the seismogram. The pens and lever systems would 

provide 

drag that amounts to damping. Presumably the loop of paper runs for 24 

hours 

so time could be measured from the start where the time of start would be 

marked on the paper loop. It is certainly an interesting mechanical device 

that could record earthquakes. Its sensitivity would depend on the lever 

system. The photograph shows what seems to be a carefully built and well 

designed system of levers that provide mechanical amplification. I hope 

Chris 

Chapman, who is an engineer, will figure out the amplification factor when 

he 

visits the museum in a couple of months.



Best regards,

Cap

__________________________________________________________



Public Seismic Network Mailing List (PSN-L)



To leave this list email PSN-L-REQUEST@.............. with 

the body of the message (first line only): unsubscribe

See http://www.seismicnet.com/maillist.html for more information.





----------------------- Headers --------------------------------

Return-Path: <larry_cochrane@..............>

Received: from  rly-zd05.mx.aol.com (rly-zd05.mail.aol.com [172.31.33.229]) 

by air-zd05.mail.aol.com (v79.27) with ESMTP id MAILINZD55-0713092142; Fri, 

13 Jul 2001 09:21:42 -0400

Received: from  sys5.webtronics.com (sys5.webtronics.com [216.100.224.130]) 

by rly-zd05.mx.aol.com (v79.20) with ESMTP id MAILRELAYINZD56-0713092126; 

Fri, 13 Jul 2001 09:21:26 -0400

Received: from imo-r08.mx.aol.com (unverified [152.163.225.104]) by 

sys5.webtronics.com

(Rockliffe SMTPRA 4.5.4) with ESMTP id <B0000049646@...................> 

for <psn-l@..............>;

Fri, 13 Jul 2001 06:16:52 -0700

Received: from CapAAVSO@.......

    by imo-r08.mx.aol.com (mail_out_v31.7.) id x.d8.8f4e1ef (3968)

    for <psn-l@..............>; Fri, 13 Jul 2001 09:15:38 -0400 (EDT)

From: CapAAVSO@.......

Message-ID: <d8.8f4e1ef.28804e7a@.......>

Date: Fri, 13 Jul 2001 09:15:38 EDT

Subject: Re: Lehman??

To: psn-l@..............

MIME-Version: 1.0

Content-Type: text/plain; charset="US-ASCII"

Content-Transfer-Encoding: 7bit

X-Mailer: AOL 4.0 for Windows 95 sub 114

Reply-To: psn-l@..............

Sender: psn-l-request@..............





who are you, why do you converse with someone else in my screen name?