Soak the gelatine for two hours in half a cupful of the water.
Boil the cupful of water, and the sugar fifteen minutes.
Hash the peaches fine, rub through a sieve, and put in the syrup. Cook five minutes, stirring all the time.
Place the sauce-pan in another of boiling water and add the gelatine. Stir for five or eight minutes, to dissolve the gelatine; then place the sauce-pan in a dish of ice water and beat the syrup until it begins to cool.
Add the whites of the eggs, and beat until the mixture begins to harden. When it will just pour, turn it into the mould, and set away to harden.
Serve with sugar and cream.
Apricot and pear sponges can be made in the same manner.