Tomato Preserves

From 1922:

Select medium size ripe tomatoes, pour boiling water over and let stand a minute. Run cold water over them, remove the skins and place a layer of tomatoes in an enamel saucepan, sprinkle one cup of sugar over every six tomatoes and four thin slices of lemon, put in six more sliced tomatoes and one cup of sugar and the four slices of lemon and repeat the same until the saucepan is half filled. Cover, set aside for six hours. Place on the stove and cook rapidly for twenty minutes or a little longer if the preserve is not thick enough.
Be sure to use firm ripe fruit. Poor tomatoes make poor preserves.