There was a book published in 1896 by a Moses Light on the Light Family of America. The book is available at the Lancaseter Co. Historical Society. While there are several known errors and confusions between the various Light families in the area it can serve as a beginning for you. Barbara Light who married Jacob Hershey is listed in this book. I have put together a GED file of the people listed in this book and it is available from http://www.aristotle.net/~klight/index.html go to the Light Page and click on the John Light link that mentions Moses Light.