Why is Danforth's statement, "We burn a hot fire here, it melts down all concealment," ironic in the context of Acts 3 and 4?

Danforth insists that no one will be able to lie in his court, and this statement is terribly ironic because the girls have been lying in his court since day one.  The entirety of the trials are absolutely founded the lies they've been telling since Betty Parris took sick.  Further, Danforth doesn't believe the people who are actually telling the truth; Proctor sacrifices his reputation by confessing the truth of his adulterous relationship with Abigail, and Danforth refuses to believe him because his wife lies to protect him.  Therefore, again, Danforth believes the lie and disbelieves the truth.  This is incredibly ironic.

Because Danforth makes this statement during Act Three, the irony certainly pervades the entirety of the act.  However, in Act Four, the stress of the trials begins to reveal characters' real identities, "melting down" any attempt they've made to make themselves seem other than they truly are: Parris is an obviously weak man who lacks conscience or backbone; Abigail and Susanna are thieves who have ruined more than Parris with their lies; Danforth shows that he cares more about retaining his authority than uncovering the truth.  Finally, all of Proctor's thinking of himself as a fraud is melted away as well and he comes to see the truth of himself: that he is actually a good man, despite his past mistakes.  Thus, the statement becomes somewhat more accurate in this act.

What does Danforth's quote "We burn a hot fire here; it melts down all concealment" in The Crucible mean?

In Act Three, Mary Warren tells Deputy Governor Danforth that Abigail and the other girls are lying. Danforth then looks at John Proctor and says to him, "We burn a hot fire here; it melts down all concealment" (Miller, 81). Danforth's statement is significant because it foreshadows Proctor's confession of his infidelity while simultaneously alluding to Hell and depicting the imagery of a crucible.

The "hot fire" symbolically represents the ominous, tense atmosphere of Salem, which is similar to Hell. The heat and melting imagery also correlate with the title of the play. A crucible is literally a container where metals and other substances can be melted at high temperatures. A crucible is also the perfect metaphor for the violent hysteria that overwhelms the community of Salem. As previously stated, the melting of "all concealment" foreshadows Proctor's subsequent confession of his infidelity. When Proctor admits that he had an affair with Abigail Williams, he reveals his secret and ruins his reputation. Danforth's statement rings true on several metaphorical levels. 

What does Danforth's quote "We burn a hot fire here; it melts down all concealment" in The Crucible mean?

Also, remember the signifigance of the title The Crucible. A scientist will tell you that it is a ring that holds a flask over a fire; a linguist will tell you that is a term for a rough trial or ordeal one undertakes. This quote combines those images at an important point in the play. Proctor is also dealing with a personal trial-- dealing with his young lover's vindictiveness and his wife's coldness as a result of their affair. Proctor's personal trial and the witchcraft trials intertwine to bring about Proctor's downfall.

What does Danforth's quote "We burn a hot fire here; it melts down all concealment" in The Crucible mean?

This quote is said in Act Three to John Proctor, just as he brings his claim that the girls, led by Abigail, are all making up the serious charges of witchcraft that they bring against so many of the people of Salem. This quote is incredibly important for a number of reasons. Firstly, it foreshadows the way that the system of "justice" does indeed melt down "all concealment," in particular focusing on John Proctor's infidelity with Abigail and his act of adultery against his wife. Secondly, it is indeed true that the court does "burn a hot fire," as is shown by the subsequent death of so many innocent lives. There is also the allusion to the fires of hell in this quote, which is rather appropriate, given the hell-like nature of the Salem witch trials and the way that so much harm was done with the intention of only achieving good.