Combine 3 1/2 cups boiling water, sugar and 1/8 teaspoon salt in saucepan; bring to a boil.
Cook for 5 minutes or until syrupy.
Stir in lemon juice; add peaches.
Reduce heat; simmer for 20 minutes, turn- ing peaches occasionally.
Transfer peaches to serving bowl.
Add butter and pinch of salt to hot syrup; stir until butter is melted.
Stir in rum; pour over peaches.
Refrigerate until ready to serve.
Serve with whipped cream.