The first deposition is brought in by Giles Corey in which he states that he got information from a man who, on the day that Ruth Putnam accused George Jacobs of witchcraft, overheard Thomas Putnam say that his daughter had given him a great gift of land.
The second deposition is brought in again by Giles Corey along with Francis Nurse, and it is a list of 91 people who give their good opinion of Martha and Rebecca and swear that they never saw them have any dealings with the devil.
The third deposition is the one that Proctor forces Mary Warren to sign stating that the girls have been lying, that Mary had never seen any sign of witchcraft and that she too was lying to the court.
A deposition refers to testimony before a court either verbal or in written form (signed by witnesses thereto). The testimony can either be accepted or rejected by the court. If it is accepted, it normally warrants further inquiry in the form of further evidence provided by witnesses.
In the witch trials, many people in Salem were arrested on charges of witchcraft, testified mostly to by the girls and by Tituba's initial allegations made under threat. This lead to many innocents being incarcerated. The three depositions brought before the court in Act 3, are examples of Salemites attempting to persuade the court about the guilt or innocence of those close to them or those they deem to have a hidden agenda in accusing others of witchcraft.
The first one who wishes to bring testimony to the court in Act 3, is Giles Corey. His wife, Martha, had been arrested on a charge of witchcraft and Giles wishes to present evidence of her innocence. He had entered the court in a huff and offended judge Danforth. He pleads that the accusers are telling lies about his wife and starts saying that he had not meant any harm when he spoke to reverend Hale about Martha reading books.
Giles weeps and says that he had broken charity with her. When reverend Hale comes to his defence and requests that judge Danforth give him a hearing, Danforth coldly dismisses his appeal and says that Giles should prepare a proper affidavit if he wishes to address the court. Herrick then removes Giles from the court.
The second deposition is brought by Francis Nurse, husband of Rebecca, who has also been incarcerated on a charge of witchcraft. Francis testifies that the girls making the accusations are all frauds. The supercilious judge, instead of listening to Francis' testimony, rather threatens him with his power by mentioning his record as a stern judge who has sentenced nearly four hundred to prison.
Francis accedes to the judge's weighty authority but insists that he is being misled. Before he can continue, Giles Corey enters with John Proctor and Mary Warren, who looks ill and exhausted. Proctor is the one who states that Mary wishes to speak to the judge - this then becomes the another deposition.
When judge Danforth addresses Mary, she does not respond but John speaks on her behalf, stating that she had 'seen no spirits.' Judge Danforth declares his surprise at this declaration. John withdraws a document from his pocket stating that Mary had signed a deposition, which the judge immediately rejects.
Judge Danforth then questions Mary about her crying out that others were witches and she says that it was a pretence. She further testifies that all the other girls were also pretending. The judge then turns his attention to John, stating that a man would go to desperate measures to defend his own and asks if this were not the case in this instance. Elizabeth, John's wife, had been arrested earlier. Danforth informs him that Elizabeth is pregnant and that the court will be lenient to her if John drops this charge. He refuses.
The judge asks John what deposition he has for the court and he mentions that he has a testament signed by good Salemites, testifying about their good opinion of Elizabeth, Rebecca Nurse and Martha Corey. The judge asks how many names there are on the list. When he is told that there are ninety-one he charges that they should all be summoned to court.
Francis Nurse is horrified at this instruction and, trembling with anger, says that he had promised the signatories that he would ensure that no harm would come to them. Judge danforth insists, however, that warrants be drawn up against those who signed the testament.
Giles Corey then also asks to present his deposition. In it, he charges that Mr Putnam coldly prompted his daughter 'to cry witchery upon George Jacobs that is now in jail.' Putnam is called in and he denies the charge. When Giles is asked to provide proof, he mentions that an honest man had told him that had heard Putnam urging his daughter to condemn the man. Judge Danforth asks him to name the person and Giles refuses, wishing to protect his informant. He is later arrested for contempt of court.
In the true sense of the definition of the word, 'deposition,' it should be clear from the above that more than three were presented to the court. The three mentioned in the question are written depositions, but a deposition can be verbal as well, as illustrated above.
It is clear that judge Danforth is not prepared to heed real evidence. He is afraid to have his authority challenged or his judgement questioned. He had already decided about the guilt of the accused and is arrogant and rude to whomever wishes the court to make a fair judgement. He sees this as a personal attack and rules the proceedings with an iron fist. It is his recalcitrance and haughtiness which eventually leads to the deaths of so many innocents.
Act III is interesting, because it illustrates how illogical the court of Salem has become. The reader sees three men, Giles Corey, Frances Nurse, and John Proctor, come to court to present several depositions in order to free their respective wives. The court is at first very hesitant to hear their depositions at all, because they do not want the accused to be released.
The first deposition is one signed by Mary Warren in which she admits that she "never saw no spirits" and that "it were all pretense, sir." John Proctor forces her to sign this deposition; she does not do so enthusiastically because she knows that Abigail will be furious.
The second deposition is signed by 91 people and brought by John Proctor when he states, "These are all landholding farmer, members of the church. If you'll notice sir -- they've known the women many years and never saw no sign that they had dealings with the Devil." These people are then ordered to be arrested so that they may be "examined" by the courts.
Lastly, Giles Corey presents a deposition that he heard from "an honest man" that Mr. Putnam encouraged his daughter to accuse George Jacobs so that he could take Jacobs' land. Giles states, "I have it from an honest man who heard Putnam say it! The day his daughter cried out on Jacobs, he said she'd given him a fair gift of land." The court wants the name of this "honest man" and Giles refuses, knowing that the man will be arrested. Giles is taken into custody for contempt of court because he will not reveal the name, and is eventually killed by pressing.
Each of these depositions is meant to show the absolute lunacy with which the court is assessing the claims of the townspeople when it comes to the accused and illustrate how absolutely unfair it is.