Preheat the oven to 325 degrees F (165 degrees C). Grease and flour a 9 inch tube pan.
In a large bowl, cream together the sugar and margarine until smooth. Beat in the eggs one at a time, then stir in the vanilla and lemon juice. Combine the flour, baking powder and salt; mix into the batter alternating with the milk just until blended. Pour into the prepared pan.
Bake for 1 hour in the preheated oven, or until a toothpick inserted into the crown comes out clean. Cool in the pan for at least 10 minutes before inverting onto a wire rack to cool completely.
