Bibliographies...ugh!

I've been beating my head against the wall for weeks over this term paper I'm doing for my history class. The class teaches methods for historical research, citing sources, writing papers, etc. My paper is dealing with the role that outspokenness and non-conformist behavior played in the Salem witch trials (really, it's not as dull as it sounds!). I've finished the paper (and heaved a sigh of relief that was, no doubt, heard around the world) and now I'm trying to do my bibliography. Sources have to be cited correctly, using Chicago Manual Style, since that's part of what my professor has been teaching us.

Now, here's what's driving me nuts. I used a book that was originally published in 1867; my copy was part of the fourth printing in 1969. My professor says that I need to show the original printing in my bibliography, but my copy of the book doesn't mention the original printing. So I checked another book and got that information. Then I wondered, do I have to cite the book I got the bibliographical information from? And what would that look like, exactly? It's like math, I tell you: the more you try to think about a problem that doesn't make sense, the harder it gets to work through.

I think I'll have to just b.s. my way through that citation and hope for the best!