Analysis of Armies in the Fire

The lamps now glitter down the street;
Faintly sound the falling feet;
And the blue even slowly falls
About the garden trees and walls.

Now in the falling of the gloom
The red fire paints the empty room:
And warmly on the roof it looks,
And flickers on the back of books.

Armies march by tower and spire
Of cities blazing, in the fire;--
Till as I gaze with staring eyes,
The armies fall, the lustre dies.

Then once again the glow returns;
Again the phantom city burns;
And down the red-hot valley, lo!
The phantom armies marching go!

Blinking embers, tell me true
Where are those armies marching to,
And what the burning city is
That crumbles in your furnaces!