IV INTRODUCTION. 



Northern Lighthouse Board, was allowed to commence opera- 

 tions, and after encountering and overcoming innumerable 

 difficulties by his indomitable skill, energy, and perseverance, 

 he at last completed the work, and had a light shown from 

 it on 1st February 1811. It is very satisfactory to be able 

 to state as testifying to the excellency of the materials used 

 in its construction, as well as to the careful and well devised 

 scheme and execution of the workmanship, that the tower 

 as yet shows no symptoms of decay, and stands as strong 

 to-day as when newly erected. 



In a highly interesting lecture which the writer of the 

 Notes delivered at Arbroath, about a year ago, he thus 

 described the lightrooin and lighting apparatus, which had 

 just been renewed, not on account of tear and wear, but to 

 bring it up to present day standard : 



" In the centre of the floor stands the revolving machinery 

 enclosed in a heavy metal case, upon which the huge lens, 

 with its supporting carriage, revolves. The lens itself a 

 marvel of the glassmaker's art is the production of a French 

 firm. Imagine a huge saucer, twelve feet in diameter, com- 

 posed of twenty concentric prisms of purest glass, each with a 

 diameter almost as much as a man may enclose with both 

 hands, terminating centrally in a sixteen inch plano-convex 

 lens or bull's-eye. Suppose the rim of this saucer to the 

 extent of four prisms be turned sharply inwards, the whole 

 set vertically on edge convexity outwards and a vertical 

 section in which the bull's-eye and three adjoining prisms 

 are alone intact projected a foot further forward, one may 

 gain some idea of that particular portion of the lens allotted 

 to the red flash, the colour of which is attained by means 

 of sheets of red glass attached inside the central section 

 and on the outside of the adjoining wings. On the opposite 

 side of the lens, and in a line with the central red section, 



