A poem is that species of composition, which is opposed to science by proposing for its immediate object, pleasure and not truth.
A poem provides delight from the whole and not from each component part.
A proper poem is one whose parts mutually support and explain each other.
A series of striking lines or distiches which make a separate whole instead of a harmonising part cannot be called a poem.
The reader should be carried forward, not merely or chiefly by the mechanical impulse of curiosity or by the restless desire to arrive at the final solution, but by the pleasurable activity of the mind excited by the journey itself.