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.
Red or yellow gas flames may be the sign of incomplete combustion, wasted gas and a serious safety hazard. With hydrocarbon flames, such as gas, the amount of oxygen supplied with the gas determines the rate of combustion, flame colour and temperature.