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The VUA geological compass : History
 
         
 
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instrument making at the VUA in the seventies

 At ca. 1970, the department of Earth Sciences at the Vrije Universiteit, Amsterdam (VUA) had the choice of using two compasses for students. The existing Silva compass, principally designed for orienteering, and the brand new, up-dated 'Clar-Breithaupt' geological compass (soon to be copied by the more economical East German 'Clar Freiberger'), a sophisticated, but relatively expensive instrument. The Clar method allowed the compass to simultaneously measure the dip and dip direction of a plane and plunge and plunge direction of a lineation with its inclination hinge attached to the turning axis of the compass lid.

Silva Expedition S Kompas

 The Silva or similar Suunto, compasses are still good, solid instruments, but mainly designed for determining geographic orientation. It lacks an accurate tool to orient the compass horizontally and vertical during measuring strike and dip respectively. However, they can be used adequately for geological purposes after attaching a little round level to the surface of the compass baseplate.

Neither of these instruments at that time met our requirements. The Silva or Suunto has the advantage of a liquid-damped compass, but is cumbersome, because it didn’t allow the dip or plunge of respectively foliation and lineation to be acquired during one measurement.

Breithaupt Cocla Stratum Compass

The Clar Breithaupt is a beautiful instrument, but too vulnerable to wear and tear during fieldwork and the air-damped needle provides a comparatively unstable platform for fast measurements, and more important, way too expensive for our students. So we decided (1970-71 ), with the consent of the Earth Sciences Faculty Board, to give it a try and produce our own geological compass.

It had to meet the following requirements:

  • (1) Applying the Clar principle;
  • (2) strong and durable;
  • (3) simple construction and easy to build;
  • (4) cheap.

    • Freiberger Geological Stratum Compass w-Mirror

    During the following 4- 5 years the produced compass was tried and progressively modified following the comments of a sizable group of graduate geology students at VUA using the new instrument during field work in the metamorphic tectonites of the Precambrian shield of Southern Finland.
     
    Brunton and other compasses have developed more sophisticated instruments of late. However, neither of them meets our goal for a simple, strong and easy to construct compass, suitable for students and particularly geologists in developing countries working for parties with restricted research funds. The VUA-compass fits these qualifications as it has proven to do so after 40 years of professional use. This is why we thought it useful to publish a file on this instrument, including photographs and blue prints.