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.
Producer gas is a mixture of flammable and nonflammable gases, mainly carbon monoxide and hydrogen in the former, and carbon dioxide and nitrogen for the latter. It burns with a lower heat than some other gases, but its great benefit is that it can be manufactured simply and relatively cheaply.