IRON MANUFACTURE. 533 
the oven, and in this way take their blast from pipes arranged above 
instead of below. 
The fire-brick stoves, represented by the ‘‘ Cowper-Siemens” pat- 
tern, and the “ Whitwell” stove depends on the principle involved in 
the regenerator steel furnaces. 
If a large number of fire-brick be brought to a high temperature in 
a closed vessel, by allowing a mixture of gas and air to burn among 
them, and then, the supply of gas and air being cut off, the blast turned 
through, the heat of the fire-brick will be imparted to it. The Whit- 
well stoves, instead of using fire-brick piled in open order, as in the re- 
generator furnace, substitute parallel brick flues, through which the 
gas flames pass. Whitwell stoves are in use in several localities in the 
State; they have the advantage of great economy in gas, of great dura- 
bility, there being no expensive pipes to replace,. and of the power of 
imparting the highest temperature to the blast ; any temperature in fact 
being attainable. They have the disadvantage of being comparatively 
expensive, at least two or more, usually three being necessary, as one 
must obviously be heating while the other is in use, and of requiring 
the attention of a person to change the blast from stove to stove. The 
regularity of the changes is important, owing to the irregularity in heat 
of the blast which will oceur if it is improperly done. The older Whit- 
well stove is made short and of comparatively large diameter; the 
newer stoves are built higher and of much less diameter in proportion 
to their length. The number of angles over which the blast has to 
pass has also been diminished, and the number of flues increased. The 
new furnace of the Cleveland Rolling Mill Co. is provided with Whit- 
well stoves of the newest pattern, of which the following description is 
furnished by the designers: ‘‘ The Whitwell stoves are 20 ft. in diame- 
ter and 70 ft. high, of the most recent type, and have a heating surface 
of 30,000 sq. ft. each. ‘These stoves each contain 250,000 fire-brick, 
laid in the forms shown. Lach stove is supplied with a cleaning crane, 
by means of which the stove coal can be cleaned in from three to four 
hours. The top is of a mitre form, and to this top are riveted a series 
of cast-iron doors, each of which gives access to a group of flues below, 
so that any part of the stove can be reached by the scraper. On each 
top is constructed a balcony, so that easy access can be had to these 
doors. ‘The air is introduced into these stoves through an arch, which 
thoroughly diffuses the same. The gas is introduced through a circular 
