Many years ago I learned "is hoist by his own petard" from Perry Mason.  I recently thought I should know why it's not "is hoisted," and undertook a search.  I finally ran out of patience.  My American Heritage simply says, "transitive verb, hoisted, hoisting, hoists. etc."  Everybody quotes the quote, but nobody talks about the past participle.  (MW doesn't give participles.) Can someone please help?

Many thanks,   - A.

Thanks, Clive.  I only know one well-known author who's audacious enough to remain unnamed: when in eternal lines to time thou grow'st - - - - and this gives life to thee. 

I read a dozen references and it fell to you to reveal the source.  Not my favorite play.  All I remember is slings & arrows.

I wonder why they've bothered to add the "d" to "petar."

Thanks again,  - A.

Edit.  Just received this week's copy of The New Yorker.  They quote from the Times: "These letters are a smoking gun that something is not right in Denmark," Judge Agresti said in a Dec. 20 hearing in Pittsburgh. 

(NY'r comment)  Downright rotten, we'd say.