The Automatic Lighthouse

Kaipara and Waitemata Echo, 24 April 1914, Page 2

The Automatic Lighthouse

+ L WORKED BY THE SUN. The lighthouse-keeper, about whom has gathered so muuh and romance, is to be driven from his post and replaced by an automatic device which lights the lamp and extinguishes it without f the aid of human hands. The inventor is a distinguished Swedish physician named Gustaf Dalen, and |he has received the Nobel Prize. It seems tragic that one who has worked to give Hgh( to the world should now be in darkness. Since perfecting his great invention, Dalen has become blind. Both the lighting and extinguishing power are operated by the action of the sun. The light may be from one hundred to seveea>l thousand candle-power, and will work for mo::th.; without any attention. Acetylene plays an important part in this invention. Mad it not been for the discovery of two French chemists, the Dalen light would not have been possible. Raw acetylene is dangerous to handle, and not easily controlled. The new process renders it comparatively harmless in working, and without risk in transportation. The acetylene is stored in large welded steel cylinders, such as are used for compressed oxygen and other gases. Dalen first inxen.ted a Hashing apparatus, whereby the light, instead of burning steadily through the twenty-four hours, was given a characteristic similar to that of an occulting apparatus in which a revolving shutter eclipses the light i every fraction of a second, the mechanism being driven by a supply of gas from a reservoir. Then he perfected what is called the " sun valve." With the lowering of the sun in the wtest, gradually the beacon light burns out, shining steadily through ' the dark hours and waning with the breaking of the dawn. During the I day it is entirely extinguished. This wizard-like performance is due to a blackened bar constructed of a material peculiarly sensitive to j light. This rod presses against a j lever which closes a valve through \ which the gas passes into the flash- '' ing apparatus. Light causes this ; sensitive bar to expand longitudinally and, as the day breaks, it gradually closes the valve till it entirely shuts off the supply of gas. The ■ waning sun, causing the bar to ', shrink, gradually opens the valve ■ and liberates the gas, so that it can pass on to the flasher. It will readily be seen that this light adapts itself perfectly to different seasons, j