Sentence:  It will be proved that a <WSD>Solarian</WSD>, supposing him to have a stature equal to our own, would do as much work as seven of our cultivators; and yet the <WSD>Solarians</WSD> are the happiest of beings; their lot is the highest degree of happiness to which we can aspire until the epoch when there shall exist stars of a more exalted rank, that are not yet to be found in our young universe. 
Meaning of the word marked with <WSD> tags:  An inhabitant of the Sun.