STATE GEOLOGIST. 297 
It is important that the mass of coal be kept from fissuring, since 
this would tend to produce carbon dioxide, thus lowering the heating 
value of the gas and increasing the generator temperature. The steam is: 
introduced for the purpose of keeping the generator temperature down, 
this being an extremely essential point upon which the success of the 
(EEN 
a E77, 
expe) TZ RCs. 
\}?eKciihkiciecZa LU NS — RO SY: SN 
SSS SSS ~ Za : N SSQss7 SS 
Se RW 
RSV puss me ae 
s BQ ~ “ 
LLL ILL LLL LLL 
Fig. 52. .Cross-section of fixed grate gas producer, 
generator hinges. The steam is decomposed into oxygen and hydrogen, 
the gas being thus enriched by the presence of the latter gas. At the 
same time it is essential that not too much steam be added, or the tem- 
perature would fall too low for its decomposition and it would merely - 
dilute the gas instead of enriching it. The following analyses represent 
an average composition by volume of bituminous producer gas: 
Per cents. 
@arboneimonoxl denen: Serine ce ie 2B U Zl-O 
© lS NVOUROVREII aches aig Garage ednam MORE ROR tahini ree Reem 8.0 120 
IMEIT SOAS Me etan mete ty er haste cml in oe a ued 2.2 Dy) 
Carbone dion cle nar to at, eon hye ec 4.1 2.0 
INIEROD en Ree eine ek rete kena A oo RAO Sind Eonar 62.0 56. 
The calorific power of bituminous gas is on the average 2809 B. T. 
U. per pound or 187 B. T. U. per cubic foot. The efficiency of the con- 
version from the coal to the gas is claimed to be 88 per cent. The 
specific gravity is nearly the same as air, about 0.97. In examining the 
