In March 1937, World Astrology featured an article by Elbert, Nikola Tesla and the Death Ray that goes into more detail.
The entire March 1937 issue is available at IAPSOP here.
PS– There is a lot of noise, online and in print, and with a recent documentary, about Tesla’s Death Ray and his own mysterious death. Here is a credible account from the Science History Institute Museum in Philadelphia, now closed for renovations but due to reopen soon.