IRON AND WOOD ROOFS FOR STOVES, &c. 
39 
frost like that of January 19th, when the thermometer fell to 12 degrees below 
zero, or 42 degrees of frost. I am induced to send you this account of the degree 
of frost at Norwood (which may be relied on, as I sat up the whole of the night 
to make my observations and calculations), thinking it might interest some of your 
numerous readers. 
Figure 1, is the elevation of the front. Figure 2, a transverse section across the 
furnace and boiler ; 3, is a longi- 
tudinal section through the centre. 
4, is a plan of the furnace, a lower 
part of the boiler ; the same 
letters refer to similar parts in 
each figure. A, is the furnace 
in which the fuel is placed, 
entirely surrounded (except the 
under side) with the boiler. 
B is the check draugtht, over n 
which the heat, flame, and 
smoke, pass to a small aperture 
C in the back of the boiler, communicating with the flues, D, surrounding the 
Fig. 2. Fig. 3. 
lower part, which unite and pass through an opening, E, in the flange on each side 
of the furnace door to the flue which surrounds the upper part, and terminates at 
the brick flue G, furnished with a damper to regulate the draught. The boiler, H, 
is in the form of an egg on the plan, with a chamber all round connected by the 
check draught, B, and surrounded with the cover to the flue, I, with an iron cap, 
