Article: Burke claimed that Bolingbroke's arguments against revealed religion could apply to all social and civil institutions as well. Lord Chesterfield and Bishop Warburton (and others) initially thought that the work was genuinely by Bolingbroke rather than a satire. All the reviews of the work were positive, with critics especially appreciative of Burke's quality of writing. Some reviewers failed to notice the ironic nature of the book, which led to Burke stating in the preface to the second edition (1757) that it was a satire.

Now answer this question: Where did Burke make it clear that his book was a satire?
in the preface to the second edition