What is the contrast presented in lines 251-264? between spontaneous joys and native charm between wanton wealth and the gloss of art between man's artifice and Nature's spontaneity between the pure soul and Nature's spontaneity

The contrast presented here is of the typical theme of Romantic literature, the conflict and resolution between man and nature.

Explanation:

The given lines are a Representative of a very Romantic concern, which is the difference between things that seem important and things that are empirically important.

What seems important is wealth which comes from man's artifice but if one understands nature's spontaneity, they will be able to find the purity of soul within them and only find in them to appreciate art.

Art deriving from nature is also a parallel theme that runs here.

a discussion of natural rights