Listen, my children, and you shall hear
of the midnight ride of paul revere,
on the eighteenth of april, in seventy-five:
hardly a man is now alive
who remembers that famous day and year.

he said to his friend, "if the british march
by land or sea from the town to-night,
hang a lantern aloft in the belfry arch
of the north church tower as a signal-light,
one, if by land, and two, if by sea;
and i on the opposite shore will be,
ready to ride and spread the alarm
through every middlesex village and farm,
for the country folk to be up and to arm."

then he said, good-night! and with muffled oar
silently rowed to the charlestown shore,
just as the moon rose over the bay,
where swinging wide at her moorings lay
the somerset, british man-of-war;
a phantom ship, with each mast and spar
across the moon like a prison-bar,
and a huge black hulk, that was magnified
by its own reflection in the tide.

read these lines from the poem.

a phantom ship, with each mast and spar
across the moon like a prison-bar,

what is the effect of comparing "each mast and spar" of the british ship to "a prison-bar"?

it emphasizes the size of the vessel.

it indicates that the crew aboard the ship are criminals.

it tells the reader that the british ship is made entirely of iron.

it suggests that the british are denying the colonists their freedom.