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PLAN OF A NEW HOT-WATER BOILER, 
BY J. ROGERS, JUN., STREATHAM COMMON- 
Having lately had occasion to apply stove-heat to a small pit, and not finding 
any of the ordinary hot-water apparatuses exactly suited to my purpose, I was 
induced to try the following experiment, and the success with which I have met 
leads me to think a knowledge of it may be useful to others, as I believe my 
apparatus to be the most effective, as well as the most economical, both in original 
construction and consumption of fuel, of any hitherto in use. 
The annexed section will afford the best explanation of my plan. 
B B B B is a cylindrical boiler, 11^ inches in diameter, enclosing a similar and con- 
centric cylindrical furnace 71 inches in diameter; each sixteen inches high, f is 
the furnace ; g the grate, two inches from the bottom of the boiler ; p the pipe, 2^ 
inches in diameter, communicating with a cast-iron pipe, 4 inches in diameter^ 9 feet 
long. 
The boiler is closed at top, having a steam valve v, and s a filling screw, 
similar to that by which oil is put into a lamp. Both ends of the cast-iron pipe are 
closed by wooden plugs, through one of which is passed the communication pipe, 
p, as close to the lower side of the pipe as possible ; while through the other a 
small air pipe is passed, as close as possible to the upper side of the pipe ; and to 
the air-pipe is attached a funnel, h. The cast-iron pipe is laid at a small inclination, 
about one inch in the nine feet, so that the end farthest from the boiler is highest : 
both the smaller pipes are passed through the hackwork of the pit, and the cast-iron 
pipe alone is within. The boiler and iron-pipe being filled with M'ater, either 
through the filling screw or the funnel of the air-pipe, a small fire is lighted in the 
furnace ; the water, heating', rapidly flows off into the cast-iron pipe^ and is replaced 
by cold, till the whole boils, when steam escapes at the valve. 
A little coke is required at first lighting, afterwards cinders are the only fuel ; 
and so slow is the combustion, that this small furnace has remained burning eleven 
hours without any attention whatever, excepting once, about two hours after it was 
lighted, to clear the furnace-bars and regulate the draught for the night. The 
