66 REPORT—1868. 
The currents of gas and air, both quite cold, rise separately through the 
regenerator chambers, ¢ and z (fig. 3), and pass up through the flues, ¢, «, and 
F, F, F (fig. 4) respectively, into the furnace above, where they meet and are 
lighted, burning and producing a moderate heat. The products of combus- 
Fig. 4.—Sectional Plan at 1, m (fig. 3). 
tion pass away through a similar set of flues at the other end of the furnace 
into the regenerator chambers c, £, (fig. 3), and thence through the flues 
m’,N’ (fig. 2), and through the gas- and air-reversing valves into the chimney- 
flue, o. The waste heat is thus deposited in the upper courses of open fire- 
brick work filling the chambers, c,, ©, (fig. 3), so heating them up, while the 
lower portion and the chimney-flue are still quite cool; then, after about an 
hour, the reversing-valves, B’ (fig. 2) (through which the air and gas are 
admitted to the furnace) are reversed, by means of the levers, Pp, and the air 
and gas enter through those regenerator chambers, £, c, (fig. 3), that have 
just been heated by the waste products of combustion, and in passing up 
through the open brickwork they become heated, and then, on meeting and 
entering into combustion in the furnace, p, p, they produce a very high tem- 
perature, probably 500° Fahr. higher than when admitted cold; the waste 
heat from such higher temperature of combustion heating up the previously 
cold regenerator chambers, c, E, to a correspondingly higher heat. 
After about an hour’s work, the reversing-valves, B’ (fig. 2), are again 
reversed, and the air and gas enter the first pair of regenerator chambers, 
c, E (fig. 3), but which are now very hot, and therefore the air and gas 
become very hot, and enter the furnace in this state, meeting and entering 
into combustion, and thus producing a still higher temperature, probably 
500° higher still, and again heating the second pair of regenerator chambers, 
c,, E,, 80 much higher, which enables them to again heat the air and gas to a 
still higher degree, when the valves, s' (fig. 2), are again reversed. Thus an 
accumulation of heat and an accession of temperature is obtained, step by step, 
so to speak, until the furnace is as hot as is required; for unless cold mate- 
rials are put in to be heated, and thus abstract heat, the temperature rises as 
long as the furnace holds together, and the supply of gas and air is con- 
tinued. The heat is at the same time so thoroughly abstracted from the pro- 
ducts of combustion by the regenerators, that the chimney-flue remains 
always quite cool. The command of the temperature of the furnace and of 
the quality of the flame is rendered complete by means of the gas and air re- 
gulating valves shown at B, in fig. 2, and by the chimney-damper. These 
are adjusted to any required extent of opening by the notched rods, a, rR, and 
8s (fig. 2), respectively, so that, having the power of producing as high a tem- 
perature as can be desired, there is also the power of varying it according to 
the requirements in each case. 
The bed of the furnace, p p (fig. 3), is of the ordinary construction, formed 
of iron plates, and is provided with water-bridges at the ends, as shown, to 
a 
