532 Scientific Proceedings, Royal Dublin Society. 



small, the annual expense of this great light is not much greater 

 than an ordinary lighthouse light. 



The extreme angles of apparatus C, if in actual operation, would 

 he cut off, as shown by the diagram, in order to give room in the 

 lighthouse lantern. The light would be but little diminished by 

 this alteration, for the extreme edges of such large lenses are but 

 feeble in their refracting effect. Indeed, it is this fact which is 

 one of the chief recommendations of the double system. A more 

 powerful beam can be transmitted through two lenses placed side 

 by side than by one lens equal in area, with one central burner, 

 even if it were possible and convenient to double the size of the 

 burner. 



My description of the mechanical part of this subject is 

 finished. A very few words on its moral aspect may be 

 allowed. Improvements for lighthouses likely to save life and 

 property may be devised, carefully thought out, and tried practi- 

 cally by practical men, may be approved by eminent men of 

 science, and endorsed by scientific societies such as this ; but if the 

 Board of Trade will not even look at them, humanity is none the 

 better. You will ask — What about the shipowners ? Are they 

 content that an improvement should be despised and neglected 

 which would save from destruction their ships and the valuable 

 property they contain ? What about the sailor ? Is it to him a 

 trifle not worth considering, that the lights which guide him in his 

 dark and perilous voyages might be doubled in illuminating poiver ? 

 Is not his interest still deeper than that of the shipowners ? Is 

 not his very life concerned ? Shipowners have indeed spoken 

 out. They have again and again memorialised the Board of 

 Trade, urging that the question should at least be investigated. 

 They have even addressed the Prime Minister to that effect. 

 There has been no response. If this wealthy and influential class 

 is thus treated with contempt, what can the poor sailor expect ? 

 Who will speak for him ? He has one friend — the public — whom 

 he serves so well in the discharge of his hazardous calling. Surely 

 the voice of public opinion will demand that justice shall be done 

 to him, and denounce the inaction of the officials who rule the 

 Board of Trade, whether their refusal to give the new system even 

 a trial arises merely from the vis inertice natural to the official 



