What is the main point of Six thousand Lessons?

What does water came out from a rock mean in this poem and why is it compared to the radio waltz? time was away and somewhere else. the waiter did not come, the clock forgot them and the radio waltz came out like water from a rock: time was away and somewhere else.

Which point(s) of view do whitman's and coleridge's speaker use ?

How does the poem’s mood and tone change in each of these stages in "o, captain! my captain! "