You may find this of interest, as I believe it may be some information,to a certain degree, of your grandfather. I just came back from an antique auction after purchasing the most elegant brass wall sconce from Arbroath Scotland with the makers mark C.Gray. After having done some research on line, I truely believe your grandfather was the manufacturer of this piece. It is actually a gimbaled brass ships chandelier stamped C.Gray 1882 Arbroath Scotland. As your grandfather was born there in 1857,the probability of this particular piece being his is extremely high. ASk your father what his profession was because this seems too much to be coincidental. If it is his work, you should be proud, as I am an avid collector of nautical antiques and this particular piece is one of the highlights of my collection.