Of Chimney Fireplaces. 523 



alterations to be made for the improvement of their 

 fireplaces. 



Directions for laying out the Work. 



If there be a grate in the chimney which is to be 

 altered, it will always be best to take it away ; and when 

 this is done, the rubbish must be removed, and the 

 hearth swept perfectly clean. \ 



Suppose the annexed figure (Plate VIII., Fig. i) to 

 represent the ground plan of such a fireplace; A B 

 being the opening of it in front, A C and B D the two 

 sides or covings, and C D the back. 



Figure 2 shows the elevation of this fireplace. 



First, draw a straight line, with chalk or with a lead- 

 pencil, upon the hearth, from one jamb to the other, 

 even with the front of the jambs. The dotted line A 

 B (Plate IX., Fig. 3) may represent this line. 



From the middle C of this line (A B) another line 

 c d is to be drawn perpendicular to it, across the hearth, 

 to the middle d of the back of the chimney. 



A person must now stand upright in the chimney, 

 with his back to the back of the chimney, and hold a 

 plumb-line to the middle of the upper part of the breast 

 of the chimney (Plate X., Fig. 5, d\ or where the canal 

 of the chimney begins to rise perpendicularly ; taking 

 care to place the line above in such a manner that the 

 plumb may fall on the line c d^ drawn on the hearth from 

 the middle of the opening of the chimney in front to 

 the middle of the back, and an assistant must mark the 

 precise place e> on that line where the plumb falls. 



This being done, and the person in the chimney hav- 

 ing quitted his station, 4 inches are to be set off on 

 the line c d, from e towards d; and the point /, where 



