A Perfect Example of Scientific Error Through Experimenter Bias and Expectation
The Deadly Cancerous E Rays and N Rays.
The Europeans were the first to believe the earth was emanating rays from deep within the earth. They called them "E Rays", or "Erdestrahlen Rays" or "Earth Rays." In 1903, a French physicist also discovered and named these strange radiations as; "N Rays" or "Hot spots." They were found in everything on earth, except green wood and some metals. Tests done by scientists around the world confirmed his findings.
They also believed the rays caused cancer.
The rays cannot be detected by any kind of instrument, the only way that they can be found is by Dowsers.
To this day in many hospitals, beds are placed in areas where E and N Rays won't be able to get to the patients, the same with most government buildings, almost sounding Feng Shui'ish. Big bucks are paid to Dowsers for finding hot spots and rearranging desks according to where the E and N Rays are known to be. Hospitals want to protect their employees from being over exposed to radiation and are said to screw-up people's auras, making them less productive during the work day.
Of course, there is no such thing as E Rays or N Rays. It was proven false by an American scientist named Robert Wood who proved the experiments were faulty and totally imaginary.
This is a perfect example of a scientific error through experimenter bias and expectation.