IN AN IMPROVED PIT. 51 



and brick-on-edge be carried up together, it will 

 be of advantage, as the whole may be steadied 

 by the introduction of a few bricks across the 

 air chamber. 



The brickwork being completed, let the 

 bearers upon which the lights will have to rest 

 and traverse, be put on, and the space between 

 them filled up with inch-thick tiles laid in cement, 

 so as to arrive at the same thickness as the 

 bearers. The tiles must be laid flush with the 

 brickwork on the inside of the pit, and project 

 one-and-a-half inch over the outer edge all 

 round ; in order to throw off the water from the 

 walls the surface being rendered perfectly even 

 by the cement, which is preferable to a coping 

 of wood, as it is more durable, and as on it the 

 lights will fit to a great nicety, if due care be 

 taken in finishing-off the work. -Some of the 

 pits here are so constructed as to copings, as to 

 be now in good condition, after having been in 

 use for a period of thirty years. 



The pit of which I have previously given an 



E 2 



