Tromp took a deep interest in dowsing and radiesthesia. He conducted experiments and came to the conclusion that dowsing is a real phenomenon due to activity of electromagnetic fields. His views on dowsing were criticized by the scientific community and have been described by critics as an example of pseudoscience.Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 294. Gardner, Martin. (2012 edition, originally published in 1957). Fads and Fallacies in the Name of Science. Dover Publications. pp. 103-106.
