My 4x-great grandmother was Isobel SPRING of Aberdeen, who married Robert SHERRET in 1796. In the parish register of Birse, where their four children were baptised, listed witnesses include "Miss Mary SPRING" and "Mr. Robert SPRING" of Aberdeen. I suspect these are siblings of Isobel. Another sister seems to be Christian SPRING, who married Archibald Farquharson, 5th laird of Finzean, in 1792 (which explains the appearance of Farquharson as a middle name in various SPRING and SHERRET descendants).
If this matches up with anyone else's research on the SPRING family in Aberdeen, I would be happy to compare notes.