Infuse the thinly cut lemon rinds, sugar and gelatine in the measured water until dissolved. Add lemon juice, whites and crushed shells of the eggs and whisk steadily until boiling-point is almost reached. Remove whisk and boil to the top of the pan. Pour in the brandy and sherry without disturbing the foam crust. Boil again to the top of the pan. Remove from the heat, cover, and leave to settle for 1 min. Strain carefully. Cool, remove froth, and mould in scalded individual moulds.