Oh why is heaven built so far,
Oh why is earth set so remote?
I cannot reach the nearest star
That hangs afloat.
I would not care to reach the moon,
One round monotonous of change;
Yet even she repeats her tune
Beyond my range.
I never watch the scattered fire
Of stars, or sun's far-trailing train,
But all my heart in one desire,
And all in vain:
For I am bound with fleshly hands,
Joy, beauty, lie beyond my scope;
I strain my heart, I stretch my hands
And catch at hope.
I love how effectively Rossetti uses that foreshortened line to end each quatrain. The idea isn't that we finish the line and have dead air, but rather that the line is slowed down to half pace and takes just as long to recite as each of the earlier lines. In slowing, the voice tends to drop a note or two and get quieter. It emphasizes the line by softening it. Just so, Michelangelo emphasizes Mary's eyes by lowering them. The effect is that the line speaks from the low down, from the depths, in keeping with its title which means in Latin, "Out of the depths."
The title is taken from the opening of Psalm 130, "Out of the depths I have cried out to you, oh Lord." It was written about 20 years before Oscar Wilde's famous letter of the same name.