Four key words in sentence two are: perplex, elucidation, originated, and devices.
These words are important because Poe's goal was to "perplex" or confuse the reader so that the solution would not be obvious early on. Also he wanted to give the detective a chance for "elucidation", or explanation, so that the detective could walk the reader through the solution bit by bit. "Originated" is important because it needs to be clear that Poe was the first to use these "devices", which is also important because it shows that we are going to find out what those devices are.