Sentence:  In a gentle breeze, the whole <WSD>body</WSD> of air, as far as the breeze extends, moves at the rate of seven or eight miles an hour; in a high wind, at the rate of seventy, eighty, or an hundred miles an hour [...] 
Meaning of the word marked with <WSD> tags:  An agglomeration of some substance, especially one that would be otherwise uncountable.