llJE Some Account of the Northern Light-houses, 



the importance attached by the Board to the unremitting con- 

 stancy of the watch, and of its regard for that punctuality which 

 we believe regulates all the details of this establishment. 



The dwelling-houses now constructed are calculated for the 

 accommodation of two families. The walls are lined with brick 

 instead of laths, and a space of two and a-half inches is left be- 

 tween to render them water-tight. They are covered with a 

 leaden-platform, defended by a parapet-wall, instead of a slated 

 roof with garrets. The slated roof was found constantly liable to 

 injury from high winds, in situations exposed, as the Light- 

 houses generally are, to the rage of every storm, and not unfre- 

 quently to the sprays of the sea, even in situations much above its 

 level. Formerly, when the attic apartments were occupied, the 

 premises became liable to accident by fire. The early light- 

 rooms were chiefly constructed of timber, lined with fire proof 

 plates ; now they are built wholly of incombustible materials. 

 The dormant sides, should there be any in the light-room, are 

 made double, with a space between, to prevent the effects of 

 condensation and moisture. For the same reason, its cupola- 

 roof consists of two shells of copper. The windows are now 

 glazed with polished plate-glass, each pane measuring about 18 

 by 30 inches, and a quarter of an inch in thickness, instead of the 

 common sash -panes of crown glass, formerly in use, which, from 

 the number of interposing astragals, obstructed the passage of 

 the light. 



The reflectors originally employed were casts in plaster of 

 Paris, from a mould formed to the parabolic curve, upon prin- 

 ciples susceptible of considerable accuracy, and were lined with 

 facetles of mirror-glass. The power of these reflectors, however, 

 was comparatively small, from the reflecting surface being com- 

 posed of numerous pieces, in each of which only one point 

 coincided with the curve of the parabola. This description of 

 reflector was, at the time of its introduction, brought under the 

 notice of the late eminent Professor Robison, who expressed a 

 doubt that, from the nature of the parabola, the beam of light 

 from the reflector would be too direct to be generally useful to 

 the mariner. But in practice they were found to be sufficiently 

 dispersive. 



The Trinity House having been at great pains to improve 

 the reflecting apparatus on the coast of England, with the advice 



