In the years 1893 - 1896 two scientists at Astrophysikalisches Observatorium Potsdam (still under its founding director Prof. Vogel), Johannes Wilsing and Julius Scheiner tried to detect the expected solar radio emission without using electronics. They applied the so-called "Fritter" effect - the decline of the Ohmic resistance between two wires in not too close contact due to the incidence of electromagnetic radiation. In contrast with other early attempts these experiments are well documented. There are two published papers (in Astronomische Nachrichten August 1896; and in Wiedemanns Annalen, also 1896) carefully describing the experiments carried out on the Telegrafenberg in Potsdam.