Spanish Dip Needle and other mechanical mags

[Lake]

Here is an interesting mechanical magnetometer:

http://www.thortech.org/thortech/en/spanish.dip.needle1.html

Any ideas for constructing it a little bit cheaper than $3000?
One idea I read from another forum was to use a liquid filled compass.
It can be turned to vertical position easier..

Another mechanical magnetometer idea:

http://www.payton.cps.k12.il.us/magnet/design/design_shop.htm

[Carl-NC]

The proper name for this is "Magnetic Dip Needle." The Spanish Dip Needle is actually a forked dowsing rod, and there are also "Spanish Needles," another type of dowsing device. The three get confused quite often.

Magnetic Dip Needles were widely used in the early 20th century, and are easily found on eBay for less than $100. They can be useful for locating large iron and black sand deposits.

- Carl