Analysis of I have never seen

I have never seen "Volcanoes"—
But, when Travellers tell
How those old—phlegmatic mountains
Usually so still—

Bear within—appalling Ordnance,
Fire, and smoke, and gun,
Taking Villages for breakfast,
And appalling Men—

If the stillness is Volcanic
In the human face
When upon a pain Titanic
Features keep their place—

If at length the smouldering anguish
Will not overcome—
And the palpitating Vineyard
In the dust, be thrown?

If some loving Antiquary,
On Resumption Morn,
Will not cry with joy "Pompeii"!
To the Hills return!