Synthesized answer
The author, Nikola Tesla, mentions that he has received "many evidences" from English scientific men and engineers that they were interested in his work [1]. He also states that these evidences have been a "great reward and encouragement" to him [1].
However, the provided passages do not detail the specific experimental evidence the author presents in his lecture. They focus more on the context of the lecture and the importance of high potential and high frequency in his experiments [1, 2]. The nature of the results and experiments themselves, beyond the general statement of their existence and the conditions required for them, is not described in these excerpts.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: Experiments with alternate currents of high potential and high frequency by Nikola Tesla Description: A lecture delivered before the Institution of Electrical Engineers, London, February 1892. Complete with illustrations.A short time ago I had the honor to bring before our American Institute of Electrical Engineers some results then arrived at by me in a novel line of work. I need not assure you that the many evidences which I have received that English scientific men and engineers were interested in this work have been for me a great reward and encouragement. I will not dwell upon…
frequency is essential for the production of the results presented is a question which, even with my present experience, would embarrass me to answer. Some of the experiments may be performed with low frequencies; but very high frequencies are desirable, not only on account of the many effects secured by their use, but also as a convenient means of obtaining, in the induction apparatus employed, the high potentials, which in their turn are necessary to the demonstration of most of the experiments here contemplated.