MECHANICS AND USEFUL ARTS. 75 



The keeper's house is octagonal in shape, and 14 feet in diame- 

 ter ; the uprights or stanchions are of cast-iron, and rest upon the 

 cap immediately over the pile-hemls, where they are secured with 

 bolts and keys: these uprights are cast with double flanehes, between 

 which 2-inch planks, tongued and grooved, are fitted horizontally, 

 and at right angles to these another series of planks are set on end or 

 vertically, and, Together, these form the side or frame of the house ; 

 upon this frame the roof is placed, and, finally, upon this the lantern 

 is set up. 



The rock is so exposed that the drilling of the holes occupied the 

 most of two seasons, although machines were used ; but these were 

 several times washed from the rock. 



The light is a fixed one, and the apparatus is composed of 15 brass 

 lamps, with reflectors 21 inches in diameter. The framing of the lan- 

 tern is of wrought-iron, and is a polygon of 1 6 faces ; height, 6 feet 6 

 inches, furnished with cast-iron ventilator; the glass, French plate, 

 44 by 24 inches, and three eighths of an inch ; the extent of il- 

 lumination is 210 degrees. Thus the entire height of the structure is 

 about 70 feet. The average weight of each complete shaft is about 

 8.200 pounds. The lantern and illuminating apparatus are about 4- 



tons in weight. 



NORWEGIAN WATER-TELESCOPES. 



THE water-telescope is an instrument three or four feet long, which 

 the people of Norway have found of so great utility that there is scarcely 

 a single fishing-boat without one, and which they carry in their 

 boats with them when they go a-fishing. When they reach the fish- 

 ing-grounds, they immerse one end of this telescope in the water, 

 and look through the glass, which shows objects some ten or fifteen fath- 

 oms deep as distinctly as if they were within a few feet of the surface. 

 When a shoal of fish comes into their bays, the Norwegians instantly 

 prepare their nets, man their boats, and go out in pursuit. The first pro- 

 cess is minutely to survey the ground with their glasses, and where they 

 find the fish swarming about in great numbers, they give the signal, and 

 surround the fish with their large draught-nets, and often catch them 

 in hundreds at a time. Without these telescopes their business would 

 often prove precarious and unprofitable, as the fish, by these glasses, 

 are as distinctly seen in the deep, clear sea of Norway, as gold-fish in 

 a crystal jar. This instrument is not only used by the fishermen, but 

 is also found aboard the navy and coasting vessels of Norway. When 

 their anchors get into foul ground, or their cables warped on a road- 

 stead, they immediately apply the glass, and, guided by it, take steps 

 to put alfto rights, which they could not do so well without the aid of 

 this rude and simple instrument, which the meanest fisherman can 

 make up with his own hands, without the aid of a craftsman. This 

 instrument has been lately adopted by the Scotch fishermen on the 

 Tay, and by its assistance they have been enabled to discover stones, 

 holes, and uneven ground, over which their nets travel, and have found 

 the telescope answer to admiration, the minutest object in twelve feet 

 I 



