He then served until the end of World War II as a laboratory manager in various companies (like Askania), especially in the area of torpedo construction.
[1] [2] In 1907, Bestelmeyer questioned the accuracy of the measurements by Walter Kaufmann regarding the speed dependence of the electromagnetic mass.
While Bucherer saw the results of his experiments as a confirmation of special relativity, his methods were criticized by Bestelmeyer, thus a polemical dispute between these two researchers arose.
It took years until those problems could be resolved, and the results of further experiments confirmed the predictions of special relativity.
[3] Bestelmeyer is also known for developing a magnetic detonator for torpedoes in 1917, for which he was awarded the Iron Cross 1st Class (although there was no time for testing this device in World War I anymore).