Call an antique dealer or the show Antique Road show (they have a website) has antique dealers & they may be in your area or able to recommend a great resource for you.
why is this in books and authors? I looked him up, but nothing mentions whether or not he married and had a family, just all his accomplishments in oceanography and whatnot. If you want to know about him:
i've bought two chandeliers from pottery barn in the past few months, and they haven't caused any problems yet. so i say go for it. if anything happens to it, just return it.