Sentence:  Secondly, The branches of Plants have been us'd in religious <WSD>Purgations</WSD> or Expiations. In the Moſaical Law there was one general kind of Sacrifice commanded for Purgation, which conſiſted of an Heifer ſacrificed and burnt to Aſhes; with which, and ſpring water, a Lee was made to ſerve for many ſorts of <WSD>Purgations</WSD>. 
Meaning of the word marked with <WSD> tags:  The process or act of cleansing from sin or guilt.