Citing books in a paper questions (Chicago Style)

Hey all, I'm writing a history paper and I have a question. I'm citing an encyclopedia (footnoting that is) but I'm actually quoting a quote that the author of the encyclopedia got from somewhere else (and has cited within the article)... should I cite the encyclopedia or the original source of the quote?

Also, when making additional footnotes from the encyclopedia, how do I shorten it? For books you do something along these lines:

Ford, 5. (Ford being name of the author, 5 being page number)

Should I just put:

Name of Encyclopedia, Page number (since the name of the author I know is not put in the first full footnote)

Or should I do this?:

Name of Encyclopedia, article name, page number

Thanks!