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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoPlainText>Dear Andrew<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Hydrogen is highly reactive in gaseous form and influences many electrochemical cells. It is detected electrically, usually in the CO cell. I agree with Harold that we should rule out some sort of instrument error, but then the CO level is compensated for the H2 meaning they both should be working if the H2 is.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>It remains an interesting problem. <o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Re the town gas, a major step in the production was to spray the hot coal with water to fracture it creating CO and H2 in the process (water gas) and when I first heard that I was amazed.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>What crazy guy thought of that??<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='font-family:Wingdings'>J</span> <o:p></o:p></p><p class=MsoPlainText>Crispin<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>>Charcoal stove, was operating, but "everything was cooled"??? Meaning <o:p></o:p></p><p class=MsoPlainText>>that there was no "serious" (as in glowing red) char in the stove, but <o:p></o:p></p><p class=MsoPlainText>>emissions were still coming off, correct?<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>If this was the case then I would expect the char would still be undergoing pyrolysis and the higher tar molecules splitting. As you all know town gas was originally made by heating coal to drive off CO and H2.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>That these molecules would survive the combustion is interesting but could simply be the dilution by other combustion products putting the air:fuel ratio out of range.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>How does a hydrogen cell sense the presence of hydrogen i.e. what mechanism is involved in the measuring instrument?<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>AJH<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p></div></body></html>