How does this sentence demonstrate an unusual use of syntax?

danced the night away, the excited party-goers.

because he is using a description to provide evidence to support his argument.

hope this could

in our power to make a world happy - to teach mankind the art of being so - to a character hitherto unknown - and to have, as it were, a new creation intrusted to our hands, are honors that command reflection, and can neither be too highly estimated,