Answer: The mast looks like it imprisons the moon, like the British imprison the colonists.
In this passage, the "phantom ship" is described. The text states that the mast and spar of the ship look as if they were imprisoning the moon. Therefore, the author compares this to a "prison-bar." It is possible that this is a reference to the way the British imprison the colonists.
If Fido's incision looks as if it is infected, you should call the veterinarian immediately. It could get worse, and the vet can help you.
Group of actors who described and commented upon the main action of a play with song, dance, and recitation.