682 HOT-WATER APPARATUS, 
of a flue, but previous to sinking them a small jjipe similar to (li h) 
must be fixed to cany off the air or they will not work well off from 
the boiler and pipes when required. 
The boiler is a close one and should be well made, and put together 
with fire cement, nuts and bolts ; it will cost about twenty shillings 
per cwt. 113 
If the boiler is only intended to heat one house, the boxes will 
not be wanted, as a pipe will be fixed on the top of the boiler, and 
the return one at (f ) : exclusive of the boxes and cocks, the expense 
of heating a house thirty feet long will amount to : 
£, .V. d. 
For Boiler 5 cwt. at 20s. per cwt 5 
Piping and Elbows 11 4 
Nuts and Bolts 301b. at 5d 12 6 
Canvass, red and white lead, &c 12 6 
£17 9 
If more houses than one to be heated the 
additional expenses of the boxes 3 
Stop-cocks for each 7 6 
