While skimming implies a quick reading of the text in order to get a general idea about it and close reading refers to in detail reading (quite the opposite), scanning is a reading technique that involves going over a text in a rapid way, so as to find some particular information you are looking for. Of course, this technique is always implemented when you know that book, essay, etc. will contain the information you need.
Answer: The purpose is to create a layer of butter between each layer of dough. It's important to refrigerate dough between each series of turns to prevent the butter from melting into the dough.
The information about the Luggnaggians which the narrator
(Gulliver) offers to his audience (English people) is their traditional
customs. At some fact of the story, Gulliver gives his view on the way to
points of views of Luggnaggians by telling it in order to make his spectators
learn the conceivable errors of others and not to do it again.