PSN-L Email List Message

Subject: Re: Seismometer on the Isle of Wight from 100 years ago
From: chrisatupw@.......
Date: Sun, 4 Aug 2013 07:14:06 -0400 (EDT)

From: George and Sandy Bush 
To: psnlist 
Sent: Wed, 31 Jul 2013 18:21
Subject: Seismometer on the Isle of Wight from 100 years ago

Here is an article that appeared on the BBC Daily E-mail
about an amateur seismologist back in the days when they were all
amateurs. It has a picture of his instrument that he constructed
using a cast-iron street lamp pole for the vertical support!

>** Island scientist who shook the world **
>A Victorian scientist who pioneered the study of earthquakes, is
>remembered on the Isle of Wight, 100 years after his death.
>< >

Hi George,

    I hope that you are both now happily installed in your new
home !

    Your Email address at gbush@....... doesn't work !!
Do you have a NEW one, please ?

    I suspect that Americans would be more likely to have
missed out on the history of John Milne, than people in the UK
or in Japan. I certainly knew about him. There was also
J A Ewing, T Gray and later on E Wichert and B B Golitzin, who
both made significant advances in seismic instruments. I have
also seen photos of John's other IOW seismometers. The
major problem back then was getting enough sensitivity.

    Mechanical gains of only x10 were about all that could be
achieved until Golitzin invented his magnet + coil + galvanometer
+ light beam + photographic recording system. The smoked
paper + scriber system which was sometimes used is surprisingly
good. Using a microscope, with x10 mechanical gain, the sense
limit was less than ~5 microns.

    My health and physical activity are continuing to improve.

    Best Wishes,

    Chris Chapman


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