Show origin of oxygen n lord kelvin showed shon ed in a recent address that all the oxygen la in the atmosphere probably came from the action of sunlight on plants lants when the earth was a globe of hot liquid liquid it contained no vegetable fuel and probably no free oxygen but as it cooled off plants appeared on its surface and these began to evolve oxygen through the medium of the sunbeams upon the oxygen ahns derived we depend tor for the maintenance of life by breathing when we burn coal or other vegetable fuel we use up oxygen and it is to plants again that we owe the restoration of the oxygen thus lost to the air it they tailed failed to keep up a sufficient supply the atmosphere mo sphere would gradually part with its oxygen and the inhabitants of the earth would gradually disappear in consequence of asphyxia alon |