Explanation on the Lines: "Full Many a Gem...Sweetness on the Desert Air" from the Poem "Elegy Written in a Country Churchyard" by Thomas Gray

This is the purple passage of the meditative poem "Elegy Written in a Country Churchyard" by Thomas Gray which is one of the five greatest elegies in English literature.
Here with his literary gesture Thomas Gray informs us that the world is the vast source which comprises uncountable treasures in her womb. We can gain a very little bit of them. But the lion share is lying scattered in the ocean and in the places where men can never go or exist. …