336 Economy of Fuel. 
g 8 388 j2 (= Bs eee 
ES eS ae ee ee oe 
B. if jf2 jg is -@.. [#22 of. 
lg . © So ~ ie eas 
23 g a2 2 > lg@e i°es Pay gas, at 
me) = See 4S igs |f25 | the m teers ates <a, 
a bo oe o= > Gon |A@Ss chearea 
Boo 18 SE 182° 2. -leBe leak 
ss |— js® [go |[E8 [SBE leet 
=F lg etd (i fsa [ss2 |528 
SS ESSER |e igs jgS8 (288 
= aes See = s a < 
213°F |67° 146 |155 |58 397) .383 
214 |63! (150'/159 55 |.365| —|Falling. 
215 = (612 11531|159 (56 | 364 Falling. 
0 (150 |160 |60 | .400 Rising gradually. 
222 (69 (153 |1611)60! | .395 Rising slowly. : 
222 \72 .\150 |168 \54 | .360) .377 “4 
223 {70 153 1162 61 | .399| _— (Rising. : 
228 (70 (158 |165 63 |.400| _‘[Rising. 
231 (68 (163 {170 [61 {.374'.g91' 
Mean, 62! 
It will be found that the least portion of temperature abstracted 
was thirty-three and a third per cent of the excess, with which the 
gas entered the drum; and this occurred when a quantity of cold 
anthracite had just been added to the fire, which greatly reduced the 
temperature of the gas. The drum in the mean time retained some 
portion of its previous temperature and imparted to the gas instead 
of taking from it, a quantity of heat. The greatest per cent was for- 
ty-seven and a half, which was abstracted when the temperature was 
rising very rapidly and when, of course, the iron of the drum, as well 
as the air of the room was acquiring temperature. It also occurred 
when the fire was covered with cinders and the fire-doors opened at 
night ; the slowness of motion in the gas having pimeae/ more than 
counterbalanced the diminution of tension in — best, * 
a greater portion of the excess to escape. 
The result of all the above observations is, that with a reiocratate 
in the room, varying from 56° to 72°, and in the entering gas, from 
100° to 231°, the number of degrees of heat abstracted by about thir- 
ty-eight ‘square feet of surface, varied, (according to the tempera- 
ture,) from 16° to 63°, showing, when compared with the peas 2 
the gas above that of the room, a portion abstracted azo to abies 
of that excess, or about one per cent for each foot ecg Tlic sur- 
face. ee os 
