Cream margarine and shortening. Add sugar and beat til light and fluffy. Add eggs, one at a time. Beat 2 minutes after each. Add milk alternately with dry ingredients, beginning and ending with dry. Melt chocolate over hot water with water. Add cream or canned milk and blend well. Grease and flour a 10" tube pan. Put 1/3 batter in pan, then 1/2 the chocolate, spread over the batter, second third of batter, second half chocolate and lastly the remaining third of batter. Bake at 350 approx 60-70 minutes or til cake tests done.