Have some water boiling ready, throw in salt enough to make it taste, and half an hour before dinner drop in the fish and boil gently at the back of the stove. Stir some butter to make it soft without melting it and mix in lemon juice and parsley. Cook potatoes with the skins on, peel when done and cut in quarters. Take up the salmon (there should be a fish kettle with a drainer or false bottom to boil fish in) serve small portions individually with the prepared butter for sauce and the cut potatoes on the same plate.