3 lbs. bitter oranges. 3 quarts water. 2 lemons. Saccharine. 1/2 tablespoonful powdered gelatine. 6 lbs. (12 cups) sugar.
Pare the oranges as thinly as possible, cut the peel into small shreds, and tie these shreds up loosely in a muslin bag.
Quarter the peeled oranges, and squeeze out the juice, reserving this. Now boil the pulp and the shreds very slowly in the water until the liquid is reduced to three pints. Strain and put back into the preserving pan with the juice, grated rinds and strained juice of the lemons, the shreds of the oranges, the gelatine and the sugar, or its equivalent in saccharine, simmer very slowly for thirty minutes, by which time it should be fairly sweet and transparent.
It must be remembered when using saccharine as a substitute for sugar that it is three hundred times as sweet as the latter, so that it is absolutely essential to measure it carefully and dissolve it thoroughly; twenty-six grains of saccharine are equivalent to one pound of sugar, and it is usually sold in tabloids weighing as nearly as possible two grains, so that thirteen of these tabloids go to one pound of sugar. When sold in powder it is usually accompanied by a small measure, which when filled level represents two grains. If not thoroughly dissolved there will be tiny atoms of the most nauseating sweetness through the marmalade. The gelatine is added to give body and stiffness to the preserve. Saccharine with the addition of the gelatine can be substituted for sugar in many cases.