When asked by Putnam if he's sent for Rev. Hale, Parris
replies, "He has much experience in all demonic arts,..." Parris
sends for Hale because of his experience, but by doing this, he
will also accomplish the other things you've listed. If Hale
can prove there are no witches, fears will be calmed, and Parris
will be seen as handling the situation responsibly, perhaps
improving his reputation in the community. Mrs. Putnam reminds them
that Hale found a witch last year, but this upsets Parris. He
replies to her, "Now, Goody Ann, they only thought that were a
witch, and I am certain there be no element of witchcraft here."
When Putnam reacts to this statement, Parris says,
"...leap not to witchcraft. I know that you--you least of
all, Thomas, would ever wish so disastrous a charge laid upon me.
We cannot leap to witchcraft. They will howl me out of Salem for
such corruption in my house."
At this time, Parris is scared to death for himself. The fact
that his own daughter is affected scares him the most because he's
afraid he'll be run out of town. Sending for Hale takes
the pressure off of Parris.