Chop or cut the rhubarb into small pieces. Add the apples, onion, and currants or raisins. Grate the orange rind fairly coarsely, remove all the pitch, and cut the fruit from the membrane. Chop the fruit and add along with any juice from the membranes. Stir in the remaining ingredients.
Mix well and cook, slowly, until thick, about 1 hour. Seal in sterile jars.