Sentence:  The Trill being the most usual <WSD>Grace</WSD>, is usually made in Closes, Cadences, and when on a long Note Exclamation or Passion is expressed, there the Trill is made in the latter part of such Note; but most usually upon binding Notes and such Notes as precede the closing Note. 
Meaning of the word marked with <WSD> tags:  A grace note.