Pickled Grapes

From 1922:

Let the grapes be at their full growth, but not ripe. Cut them into small bunches and put them into a stone jar with vine leaves between every layer, until the jar is full. Bring to boiling point as much water as will fill the jar and add salt to the water until the mixture will allow an egg to float in it. Strain it and let it get cold. Then pour it over the grapes and leaves. Cover with a cloth and leave for two days. Then take out the grapes and dry them gently with a cloth. Wipe the jar very clean and dry. Put some fresh vine leaves at the bottom. Put in the grapes and lay more vine leaves on top. Boil together vinegar, water, and sugar in the proportion of two quarts of vinegar to one quart of water and 1 lb. of sugar. Let the mixture boil for a little while and skim well. Allow it to become cold and pour it over the grapes. Use a thin piece of board wrapped in flannel on top of the jar to keep the grapes under the pickle. Tie down with bladder.