Sentence:  By this my Lady may judge what reasons I had to write what I did of the practising of the padri, amongst whom Mr. Jo. Ger[?ard] was by the gentleman precisely named to be one of the parties that was a chief <WSD>intercourser</WSD>. 
Meaning of the word marked with <WSD> tags:  Someone or something that engages in social or business intercourse.