 The case is made famous because of a letter Lydia had written to Adam Smith, a friend and distant relative of Sir Charles, requesting his assistance in reconciling the father and daughter.Douglas is buried in the ground south of the church in Greyfriars Kirkyard in Edinburgh and a memorial lies on the outer south face of the church near the east gable.Sir Charles was known as a mechanical genius, and many of his suggestions for improvements on naval vessels, including the substitution of flintlocks for matches, were adopted by the Admiralty for the entire Royal Navy.