This section is from the book "Preserving And Pickling", by Mary M. Wright. Also available from Amazon: Preserving and Pickling: Two Hundred Recipes for Preserves, Jellies, Jams, Marmalades, Pickles, Relishes and Other Good Things.
To each seven pounds of tomatoes use about one-half dozen medium-sized onions, sliced, three pounds of sugar, one pint of strong vinegar, and one pint of water, an ounce of cinnamon, and one-half ounce each of cloves and allspice-or, better, two ounces of mixed spices. Cover the tomatoes with a brine, using about one cupful of salt to a gallon of water. In the morning drain off well. Place the vinegar, sugar, spices (tied in a muslin bag), and the tomatoes in a preserving kettle and simmer slowly until tender. Put into jars and seal. If mixed spices are not used add a teaspoonful of whole pepper.