In the late spring of my last undergraduate year, my adviser, Professor Hal Mooney, introduced me to Gordon Bath, a geophysicist with the US Geological Survey. Gordon was promoting a project to measure the earth’s magnetic field using a truck mounted magnetometer.
Gordon was interested in high-resolution research on the earth’s magnetic field. Methods then existing for measuring the earth’s magnetic field at ground level were slow and cumbersome. At that time, to do a magnetic traverse you had to set up a tripod, point it north, put a mechanical magnetometer on the tripod, adjust it for balance, and take a reading. Then you had to pack everything. move a few feet along your traverse line and repeat the whole procedure again. A really fast operator could do one reading a minute, at best. Gordon argued that a continuously recording magnetometer mounted in a truck would be far more efficient, even if traversing speed could only be one or two miles per hour.
Such magnetometers had been used for submarine detection during World War II. They were later modified to do magnetic traversing while installed in an airplane flying at least 500 feet above the earth. The electronic console weighed over 60 pounds. The sensing element was five feet long and fragile.
The sensing element would be mounted in a nonmagnetic trailer. The trailer had to be a long one, to separate the sensing element from the magnetic effect of the steel truck.
Gordon wasn’t interested in instrument development, he only wanted to interpret results. The USGS had nobody available for such a project, so Gordon wanted to hire a graduate student to do it.
Happily, I got the job. I flew to Washington, DC, got a magnetometer, took it to Minnesota and mounted it in a truck and nonmagnetic trailer that I had to design and build.
We made the trailer out of wood, fastened together with brass bolts. Wheels were from a light aircraft that had crashed. For shock absorbers we used old tire carcasses.
It was a crazy looking getup, but it worked. Soon we were driving down highways at road speed, collecting magnetic data.