 (The first recorded use of a galvanometer to receive radio signals was by John Fleming in 1904.However, he used a two element vacuum-tube to convert the high-frequency alternating current to direct current in order to allow the galvanometer to work).Appleby noted that Loomis' notebooks did not include any information about a specific type of galvanometer, and "there are only meager details of the equipment used by Dr. Loomis to receive or detect these oscillations at his receiving station" because "all that he left was a few rough sketches lacking the details of construction".