34 MR. JOHN GRAHAM ON CONSUMPTION 
6. A supplementary boiler, under the circum- 
stances above described, gives a saving of ......... 
7. When numerous cast iron pipes are substi- 
tuted for the supplementary boiler, and mechani- 
cal means are adopted to keep their surface clear 
of soot, a saving may, under the circumstances 
deseribed, he*expected WO S05. o. es cc eves fea xcomeas 
8. The flues round a boiler, when they come to 
be coated to the extent of one-eighth of an inch 
with soot, are of little or no use in raising steam. 
9. If the sides and bottom of the boiler exposed 
in the flues (where such flues exist) be scraped 
once a week clean from soot, a saving will ensue 
Ol SUOOE -<.... dese tena ceca? rest oewske® pak atameen senses 
10. It is advantageous to convert the side flues 
at once into a wide flame-bed (where it is practica- 
ble), the flame and draught being spread out thin 
and going up nearly to the water mark on each 
side, and led straight on to the chimney. By such 
means the bottom of the boiler is preserved for its 
whole length free from soot, and there is an effec- 
tive radiation from the hot bricks of the bed. 
11. A very slight difference in the setting alone 
of the same boiler may readily produce a differ- 
ence in the result amounting tO ..........ceseeeeees 
In extreme cases of bad setting, as may be seen 
at Fig. 14, of course a much larger loss 
than this may be looked for. 
12. The difference between a boiler of one shape 
properly set, and another boiler of a different 
shape improperly set, but both clean and in good 
order, may readily amount to ............:c:eeeeeeee 
In some cases even a greater difference is pos- 
sible. 
15 pe 
2pect 
21 p ct 
42 p ef 
