“A new form of electric flashlight has been installed in the lighthouse tower at Heligoland[i] by the Siemens-Schukertwerke, of Nuremberg, Germany,” stated the August 22, 1903 issue of Scientific American. “There are three lower searchlights arranged 120 degrees apart, and another mounted upon the top, all operated automatically and driven by electric motors,” added the article titled “Modern Searchlights.” “The carbons, which are fed by automatic mechanism are placed in a horizontal position, as is usual with most large searchlights. The intensity of the light is 30 million candle power as a minimum, and the maximum current used is 100 amperes. The light flashes occur every 5 seconds, and they remain in one position only .1 second.”
“The three searchlights mounted on the lower platform 120 degrees apart have mirrors, 29 inches in diameter and utilize a direct current of 34 amperes each, the platform revolving at the rate of four revolutions per minute,” added Frank C. Perkins, the author of the article. “The electrical apparatus was constructed by the Elektricitats-Actiengesellschaft, formerly Schukert & Company of Nuremburg. The current is supplied to the tower of lights by a lead iron-armored covered cable connected with the power station. The power plant consists of two steam engines directly connected to dynamos of 216 amperes capacity at a pressure of 75 volts.
The Heligoland (Helgoland) Lighthouse and its four powerful flashlights or carbon arc searchlights of 1903
“This new electric beacon is to take the place of the old petroleum light that so long flashed out its danger signals at the mouth of the river Elbe. The new electric light is probably the most powerful at present in operation. Apart from its enormous power, the Heligoland lighthouse is noteworthy for the fact that a return has been made to the old form of parabolic mirror, with a light in the focus [like the ancient Pharos lighthouse used], instead of the usual Fresnel lenses and prisms.
“The mirrors of the Heligoland light consist each of a piece of silvered glass. No protection against weather is provided in front of the light, and it is asserted that none is needed. Besides the three mirrors mentioned, a fourth mirror and lamp is provided, which will turn three times as rapidly, but which, it is said, will be used only in cases of emergency.
Locations of some of the nineteenth-century European lighthouses that brandished electric carbon arc beacons, excluding Hornum
“The duration of one-tenth of a second for the flash, a characteristic of most French beacon lights, is here adopted for the first time in Germany. It is, however, a question whether three brief durations have not been carried to an extreme. Undoubtedly one-tenth of a second is sufficient to make the maximum impression on the eye, when the light is brilliant. But with a hazy atmosphere, and the light much diminished, it is doubtful whether a longer duration should not be allowed. The experiment will be watched with great interest, both on account of the bold deviation from the ordinary plan which has been so long followed, and also on the ground of economy, which is claimed for the new method. It is stated that on the first night of trial the light was seen at the pier at Busum, a distance of 40 miles, which in itself seems sufficient to clear away all doubts of the visibility of a flash of short duration.”
[i]“Heligoland” is an English term for the German word “Helgoland.” The British gave up the North Sea island upon which the lighthouse was located to the Germans by virtue of the Heligoland-Zanzibar Treaty of 1890. The Electric Mirror on the Pharos Lighthouse and Other Ancient Lighting provides more information on this electric lighthouse and http://ancientskyscraper.com/85001.html is a site well worth checking out!
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