A colleague of mine is working on a book of Thoreau's letters and a question was raised as to whether we could use an AD ligature (as in A.D. or Anno Domini) in the text. I had never seen one and was curious to find out more about it.
A quick search revealed this Flickr photo of the ligature on a bell in Boston. The quality of the photograph is terrible and that's all I was able to find.
I'm hoping someone here is more familiar with this ligature and can point me to some other examples of it.