Measurements and Observations. 
173 
Clinkering whilst running. — Better provision was made for 
this operation in some of the producers than in others as regards 
the arrangements of the doors, and such producers are obviously 
better suited for continuous running and for working with 
inferior fuels. If the ash door is opened for clinkering whilst 
running, an undue amount of dry air enters the furnace, that 
is to say, there is insufficient steam. In the Mersey producer 
a water tap was fitted which could be utilised for temporarily 
increasing the amount of steam when clinkering. A can of 
water emptied on the grate practically answers the same purpose. 
Chances of explosion. — A careful examination showed that, 
except from carelessness on the part of the attendant, the 
chances of a harmful explosion are practically nil. To cause 
an explosion it would be necessary for the attendant to open 
the feeding door to the hopper at the same time as the valve 
communicating from the hopper to the furnace. In the case 
of the Mersey producer, the hopper was so arranged that such 
a through communication is impossible. A similar provision 
might be adopted with advantage in other cases. A slight 
explosion occurred on starting the National engine on Monday, 
June 18, when opening the firedoor, and in another case 
there was a slight explosion and flame when “ blowing up ” 
the producer. As already pointed out, the water seal of the 
scrubber prevents gas getting back and acts as a safety valve. 
Chances of poisoning. — Since the gas produced contains a 
large amount of carbonic oxide, which is of a very poisonous 
nature, and being inodorous may easily escape detection, the 
chances of poisoning were carefully considered. When the 
engine is working the pressure in the producer is below that 
of the atmosphere, and therefore any leakage would be into the 
producer. It is therefore when the producer is being started, 
or opened up after running, that there is any real danger of 
poisoning ; but an accident could only happen through gross 
carelessness.^ When the producer is being started there is 
a pressure in it due to the fan ; and to reduce the effort of 
blowing, and get rid of the air in the pipes, &c., a large vent 
pipe is opened by means of a valve. The outlet of this pipe 
should be carried outside the building where the discharge of 
gas can do no harm. A small cock has to be opened to test 
the gas at starting, and the arrangement of this cock was better 
in some of the plants than in others. 
Fire risk. — There did not appear to be any serious fire risk 
with any of these suction producers ; no more in fact than there 
would be with a slow combustion stove. 
General reliability. — The duration of the trials was too 
short to admit of the trials themselves discriminating between 
a great many of the plants in this respect. The matter had 
