I9OI-2 TRANSACTIONS. 5I 



Modern Types of Danger Warnings 

 on the Sea Coast. 



By Lt.-Col. Wm. P. Anderson, M. Can. Soc, CB. 



\^Read 13th December^ ipo/.'j 



Lighihouses. From the earliest dawn of commerce, 

 which is coeval with the dawn of civilization, the necessity 

 for danger warnings on the sea coast has been recognized. 

 300 years B. C. the pharos of Alexandria, the prototype of 

 our modern lighthouse, was one of the seven wonders of the 

 world, but this was crowned by the uncertain and rude light 

 afforded by an open fire. The historic lighthouse of Corduan, 

 at the mouth of the Garonne, built at the close of the sixteen- 

 th century, remains to-day, in point of architectural grandeur, 

 the noblest edifice of its kind in the World. It, too, was first 

 illumined by burning billets of oak in a chauffeur at the top. 

 It was not until 1807 that the feeble light from a chandelier 

 filled with 10 lbs. of tallow candles was supplanted in the 

 famous Kddystone lighthouse by lamps, reinforced by para- 

 boloidal reflectors, so that improved methods of lighthouse 

 illumination began less than a hundred years ago. 



Argand's accidental discovery that the superposition over 

 an oil flame of a glass cylinder would, by increasing the 

 draught, that is the supply of oxygen, vastly increase the 

 brilliancy and steadiness of the light, was the first step in the 

 improvement of illuminating apparatus. 



The direction of a considerable proportion of the beams of 

 light by placing the flame in the focus of a paraboloidal reflec- 



