marconi-wi: Magnetic detector
In 1895, Ernest Rutherford, an English scientist, was able to detect signals transmittted a mile away, using a magnetometer, a device used for measuring the strength of magnetic fields. Rutherford's research was based on the prior work of Lord Rayleigh and other scientists studying oscillatory currents. Rutherford attached an antenna to the magnetometer; the received signal deflected the needle of the magnetometer, and thus, an early "magnetic detector" had been discovered. Marconi further developed the work of Rutherford, and in 1902 he developed his magnetic detector. The first "Maggie" (the nickname widely used for the magnetic detector) was installed in the Italian Navy's warship the Carlo Alberto in 1903. Magnetic detectors were very reliable for shipboard communication and were the primary detectors installed on European vessels from 1903 to 1912, replacing coherer type detectors. In fact, because of their reliability, magnetic detectors were used as back-up detectors on many ships into World War I to supplement crystal and later valve detectors.
(Text based on an article by Howard Stone.)
The only drawback of this very good detector indead was that it had to be winded up every two hours. There are rumors that the one ship where the crew saw that Titanic believed that they do some firework bacause the "Maggie" did not detect a stress signal - because the operater had forgotten to wind it up.
I still do not know if the story is true or not. I only know that I still miss a Maggie to be placed beside my "Multiple Tuner" from Marconi because those two sets worked together ideally. RMorg keeps me so busy that I did not yet photograph the "Multiple Tuner" and put it into the database - what a shame :-(