Sentence:  Theſe, who have nature's ſteps with care purſued,<br />That matter is with ac&#8205;tive force endued,<br />That all its parts magnetic power exert,<br />And to each other <WSD>gravitate</WSD>, aſſert. 
Meaning of the word marked with <WSD> tags:  To move under the force of gravity.