ON THE MANUFACTURE OF IRON. 7538 
great expense in the necessary gas apparatus, leads him to persevere, in the 
hope that even the objections he admits to exist will vanish with the know- 
ledge which time and patience alone can secure. 
It is, however, reasonable to suppose, as far as a mere question of fuel is 
concerned, that the combustion of the carbonic oxide at the top of a furnace 
must heat the materials to a greater or less extent, and whatever this may 
amount to will be a saying pro tanto lower down the furnace. 
To ascertain, if possible, what amount of heat was really imparted to the 
contents of a blast-furnace by the combustion of the carbonic oxide at the top, 
an examination has been made within the last few days of two furnaces at 
the Clarence Works, one open-topped, and the other close-topped. At the 
former the gases were burnt, and from the latter they were conducted away 
unconsumed. Both furnaces were of the same construction, and both were 
using materials similar in quantity and quality, and producing the same kind 
of iron. In both instances the temperature was taken 8 feet below the charging 
plates, At the close-topped furnace the following result was obtained :— 
Time of observation. Temperature. 
pS lls Me wae, SO Gn ie 
2.30 Ae - <7 eLOAG 
2 40 a. Pee wc SOFO 
ates a aes we) LIGy 
3 50 _ = oa. Gedo 
Put on 56 ewt. materials 3 20 ce = sis0 [ZA0 
3 30 rr se n/s| sEZOOR. seated MEATIE, ote 1121° F, 
Day following. 
Time of observation ...... givens. gh 200 ess 
Temperature ..........0000. II7S° sco 1227° we. 1275° «.. Mean temp. 1226° 
Put on 76 ewt. materials 2 sd” ane "cee, Shea eR emmEL CORED Taeapeens .1240 
Day succeeding. 
Time of observation ...... 3%20™ ... 3@30™... 3735™ ... 3h 55m 
BHETPCLALUTC' ...cscccecssnce 1305° ... 1282° ... 1282° ... 1415° Mean 1321° 
ientronrso Gwt. materials’ 42 5™ 0, 14. | ooh Ue eves) evel Lemp. Tage 
alee ES a Bi ao™ sti siespll aes el eeaeeeneees » 1438 
The mean of these observations indicates 1200 degrees as being the 
probable temperature of a close-topped furnace 8 feet below the charging 
plates. 
An attempt was then made to ascertain the temperature of the gases at a 
point 8 feet below the charging plates of the open-topped furnace. One ob- 
servation only was obtained, which indicated 1692 degrees. 
In all these experiments the temperature was ascertained by heating a 
cylinder of copper of a given size, and ascertaining the effect it had on an 
accurately measured quantity of water. In the case of the open-topped 
furnace the temperature was so high that this apparatus became unmanage- 
able, the copper getting so hot that the water was thrown violently out of 
the vessel containing it. Looking at the single observation obtained and 
subsequent appearances, the temperature of the gases in an open-topped 
furnace will probably be about 1800 degrees, or 600 degrees above that of 
the close-topped furnace, the datum line in each case being, as before stated, 
8 feet below the charging plates. 
Temperature of escaping Gases from Furnaces.—Scheerer gives 572° F, as 
ae pee aint of the upper zone of a blast-furnace. The writer recently 
63. 30 
