Rhubarb Chutney

From 1922:

Take 6 lb. of rhubarb, 1 ½ lb. brown sugar, 2 oz. garlic, juice of 3 lemons, 5 large tomatoes, a saltspoonful cayenne, 2 onions, ¼ lb. salt and a little vinegar. Skin the rhubarb, cut into small pieces, put it in a preserving pan with just enough vinegar to cover. Bring to the boil. Chop the garlic and the onions, skin and mash the tomatoes with a fork. Add all the ingredients to the rhubarb, boil again, stirring all the time. Let it cook 10 minutes after it boils, allow it to cool, put into jars and cover in the usual way.