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.
Gas explosion. A gas explosion is an explosion resulting from a gas leak in the presence of an ignition source. The principal explosive gases are natural gas, methane, propane and butane, because they are widely used for heating purposes. However, many other gases, like hydrogen, are combustible and have caused explosions in the past.