The speech standard of the Ming and Qing empires was called Mandarin language by European missionaries, translating the Chinese name Guanhua (the language of the officials) for this speech standard, which was current already in the Ming Dynasty.
Producer gas is made by blowing air through an incandescent fuel bed (commonly coke or coal) in a gas producer. The reaction of fuel with insufficient air for total combustion produces carbon monoxide (CO); this reaction is exothermic and self-sustaining.
With enough oxygen, you get complete combustion and an LPG (Propane) flame burns at a temperature of around 1,980Â°C. For Natural Gas (Methane), the temperature is about 1,960Â°C. A yellow gas flame is indicative of incomplete combustion and carbon monoxide emissions. Yellow gas flames only burn at around 1,000 Â°C.