In a message dated 04/05/02, hammond@........... writes:

> Meredith, I think this particular magnetometer has one or more small magnets 
> attached to a hair-like quartz fibre held vertically and under tension.

Hi Bob, 

      Horizontal field magnetometers normally have horizontal viewing 
systems, not a vertical one like this instrument. It could be an instrument 
for measuring vertical magnetic field changes. They have two horizontal 
magnets and a mirror on a horizontal quartz spring + suspension filament + 
mirror. The quartz components were made as an integral system, fused together 
and are not repairable. 

> Ambient light (coming in from that long frosted slit on the top and side of 
> the instrument) shines on a tiny mirror which is also attached to the 
> quartz fibre.  Any perturbation of the magnetic field causes the magnet(s) 
> and the mirror to move
> and thus moving the reflected light beam on a scale.  The scale is read 
> through the lens at the top of the instrument.

       A calibrated ground glass scale may be illuminated by light from the 
window and viewed by a lens + graduated eyepiece from it's reflection in the 
mirror.

> If the quartz fibre is broken, the instrument is useless.  I haven't found 
> 

       One thing that puzzles me is that while the base swivels, there does 
not seem to be a graduation ring on it. There is no obvious clamping 
mechanism. There is no offset adjustment knob on the side that you can see. I 
would have expected the lady to have shown it if there were one. Perhaps 
someone might send the photo to Sprengnether? I am rather doubtful about the 
box being cherry wood. Mahogany was usually used for instrument cases.

       Regards,

       Chris Chapman
In a message dated 04/05/02, hammond@........... writes:



Meredi
th, I think this particular magnetometer has one or more small magnets attached to a hair-like quartz fibre held vertically and
 under tension.




Hi Bob, 



      Horizontal field magnetometers normally have horizontal viewing systems, not a vertical one 
like this instrument. It could be an instrument for measuring vertical magnetic field changes. They have two horizontal magnets
 and a mirror on a horizontal quartz spring + suspension filament + mirror. The quartz components were made as an integral syst
em, fused together and are not repairable. 



Ambient light (coming in from that long frosted slit on
 the top and side of the instrument) shines on a tiny mirror which is also attached to the quartz fibre.  Any perturbation
 of the magnetic field causes the magnet(s) and the mirror to move

and thus moving the reflected light beam on a scale.  The scale is read 

through the lens at the top of the instrument.




       A calibr
ated ground glass scale may be illuminated by light from the window and viewed by a lens + graduated eyepiece from it's reflect
ion in the mirror.



If the quartz fibre is broken, the instrument is useles
s.  I haven't found 

a source for them.



       One thing that puzzles me is that while the base swivels, there does not seem to be a 
graduation ring on it. There is no obvious clamping mechanism. There is no offset adjustment knob on the side that you can see.
 I would have expected the lady to have shown it if there were one. Perhaps someone might send the photo to Sprengnether? I am 
rather doubtful about the box being cherry wood. Mahogany was usually used for instrument cases.



       Regards,



       Chris Chapman