102 BRICKWORK. 



Eleven benches of retorts set complete = 220 ; cost of retorts =268 2s. 6d. 



The house contained 55 retorts, allowing two benches of five retorts each 

 for repairs. The coal carbonized by the remaining 45 retorts was 360 bushels, 

 or 270 cwt. in twenty-four hours, producing 1 17,000 cubic feet of gas. 



A retort-house, 200 feet long and 54 feet wide (in other respects the same 

 as that exhibited at Plate IX.), will cost 



s. d. 

 Brickwork in outside walls, iron girders, flagged firing-floor 



and centre portion for supporting retort-benches - 3950 



Wrought-iron roof, slated - 700 



Chimney, 120 feet high 180 



4830 

 250 retorts set in a similar manner to those shown in Plates I. 



and II., including hydraulic main, dip-pipes, brickwork, 



complete ------- 5000 



Total cost of retort-house when furnished - - 9830 



The cost of building depends upon the price of bricks, lime, labour, etc., 

 and will vary in different localities. 



CONSTRUCTION OF CHIMNEYS. 



PREVIOUS to entering upon the particulars of the construction of chimneys, 

 I would remark, that it may afterwards be found convenient, from an increase 

 in the number of retorts, to have a chimney built considerably larger than is 

 necessary for the actual number for which it is erected ; while the expense 

 bears a small ratio to the increase of size. 



The draught absolutely required for the proper combustion of the fuel be- 

 neath the retorts is little ; indeed, that usually given to a common coke-oven 

 would be sufficient. It is necessary to build a high chimney, however, to 

 carry off the smoke, which, if not allowed to spread, would become a nuisance 

 to the neighbourhood. The height of a chimney does not decrease the quan- 

 tity of smoke, but distributes it over a larger surface and causes less incon- 

 venience. 



To obviate the excess of draught, it is advisable to make an opening into 

 the shaft communicating with the external air. The dampers of the retort- 



