1900-2 TRANSACrpNS. 53 



ination by this means. Mr. Emmerson of this city has 

 shown me a lamp in which oil in a vapourized form is burned 

 under an incandescent mantle. This promises a brilliant and 

 cheap light, if mantles less fragile than those now in the 

 market can be secured. 



Acetylene also promises good results, when a perfect gas 

 generator shall have been invented. Heretofore so much 

 practical difficulty has arisen in producing pure gas, in pro- 

 ducing it economically in the small quantities required in a 

 lighthouse, and in preventing the mechanism from freezing, 

 that acetylene has not yet supplanted oil in any of our light- 

 houses. 



Electric light can only be- profitably employed when the 

 supply can be drawn from a commercial source. To instal 

 and run an independent plant at a light station is so expensive, 

 and is accompanied by so many practical difficulties, that even 

 rich lighthouse boards, like those of England and France 

 have extended the installation of electric lighthouses very 

 slowly. In Canada we have a few lighthouses supplied by 

 corporations producing electricity in large quantities. Ad- 

 vantage has been taken of the facility with which the electric 

 current can be turned off and on, to make the light at Port 

 Dalhousie occulting, by a simple clockwork ; and to alter- 

 nately light a lamp and operate a fog trumpet on a beacon in 

 Victoria harbour. 



So far as I can ascertain, Canada is the first country that 

 has utilized an alternating current in an occulted light, and 

 Mr. Trudeau of Ottawa is the inventor of the first electric 

 fog alarm. 



It has always been a question in my mind whether there 

 was any great advantage in multiplying the initial intensity 

 of light in the way in which the superposed burners and other 

 large lamps do multiply it. In clear weather any ordinary 

 good strong light is visible to the horizon of the lighthouse, 

 and this is especially true of the clear atmosphere of Canada. 

 In thick fog the most powerful light is entirely useless at a 



