Kate, I would advise a trip to the Quaker Archives at Swarthmore if you are able. My last trip there turned up many interesting (though not linked)Whiteside entries. The Whiteside that I found was an Irish Quaker who at a later time owned land in Mill Creek then across the border in New London-Britain. When the British (on their way to Philadelphia)burned his farm, he became a Capt. William Whiteside under Col. Hannum of Media, PA. Not unusual for some Quakers to end up in the military. Seemed to happen with the Irish Quakers ..