Cherry Jelly with Kirsch

Stone three pounds of cherries, pound six ounces of the kernels with one pound of currants and strain it through a sieve. Put the cherries in a copper pan on a slow fire and reduce to half, then add three pounds of sugar and one pound of the strained currant and kernel juice, and continue to cook until a drop of it placed on a flat surface will not spread; now put in half a gill of kirsch and pour at once into jars to leave in a cool place until thoroughly cold; cover with a round of paper dipped in brandy, and close the pots hermetically with their respective covers.