Daiches says: "Moonlight for Arnold does not go with roses and romance, but with melancholy, meditation, and sometimes even despair." Elaborate with reference to "Dover Beach."
In Dover Beach, Matthew Arnold describes a moonlit scene that at first appears peaceful, and with the right treatment, could certainly be romantic. In the first six lines, we learn that "The sea is calm," "the moon lies fair," the bay is "tranquil," and the night air is "sweet." But, beginning with the warning "Only" in line seven, the poet's thoughts quickly start to take him down a darker path, one that will end, in the last two lines, in confusion and chaos.
First he evokes the "spray" thrown up from the waves. Spray is not calm or tranquil. It might still be romantic, but it can also be shocking and cold. Then he refers to the "moon-blanched land." The word "blanched" evokes something that has had the color leached out of it. We might think of ghosts, driftwood, or even old bones. Then there is the "grating roar/Of pebbles, which the waves draw back, and fling." Grating and roar are both unpleasant words and give us a sense of disquiet. Finally, at the end of the first stanza, Arnold comes right out and says that sound of the waves and pebbles "bring[s]/The eternal note of sadness in."
The second stanza gives us an explicit reason why the sound of the waves should make a person feel sad: Socrates once compared the rhythm of the waves to the "turbid ebb and flow/Of human misery." This is not just arbitrary. There are good reasons that waves, with the way they keep coming at the shore with pauses in between, and the way they batter and erode, might remind people of the troubles that keep coming back to beset us in this sad world.
There are also good reasons that waves observed by moonlight might have an even more melancholy effect. People tend to be thoughtful and introspective at night, as the bustle of the day retreats and the mind limbers up before sleep. People's fears also seem bigger at night. Things look different by moonlight than by sunlight: more beautiful and romantic, perhaps, but also a bit surreal. Besides romance and roses, moonlight is also associated with ghosts and graveyards, not to mention nighttime fevers, storms, raids, and ambushes. Clearly, Arnold feels all this as he looks at the beach.
In the third stanza, Arnold speaks of another sea, the "Sea of Faith." This was a good sea, one which protected and beautified the edges of the world. But unlike the physical sea, which rises and lowers with the tides, the Sea of Faith is only retreating, leaving the world (especially at its "edges," which might represent the realm of the spiritual or the unknown), abandoned ("drear") and unprotected ("naked"). This extended metaphor expresses Arnold's sense that the world is steadily becoming less magical, less spiritual, harsher and more dreary. And he does not see an end to the process: "I only hear/Its melancholy, long, withdrawing roar."
By the last stanza, Arnold has left behind all references to the actual sea or moonlight, and is completely consumed by the vision of human suffering to which they have led him. "This world .../Hath really neither joy.../...nor peace, nor help for pain." Arnold is describing a world which has been abandoned by God. By the last three lines, the world does not even seem to offer the beauties of nature, such as beaches or moonlight. All that is left in Arnold's vision is human evil and confusion: armies chasing each other on a "darkling plain": a plain over which the light is rapidly dying.