Who brought this to pass?
Who has brought the flaming imperial anger?
Who has brought the army with drums and with kettle-drums?
Barbarous kings.
A gracious spring, turned to blood-ravenous autumn,
A turmoil of wars-men, spread over the middle kingdom,
Three hundred and sixty thousand,
And sorrow, sorrow like rain.

Poetry is a sort of inspired mathematics, which gives us equations, not for abstract figures, triangles, spheres, and the like, but for the human emotions. If one has a mind which inclines to magic rather than science, one will prefer to speak of these equations as spells or incantations; it sounds more arcane, mysterious, recondite.