This section is from the book "Practical Cooking And Serving", by Janet McKenzie Hill. Also available from Amazon: Practical Cooking and Serving: A Complete Manual of How to Select, Prepare, and Serve Food [1919].
Do not gather the currants just after a rain; extract the juice by pressing a few at a time in a cloth, then let drain through a cloth without pressure. Let as many cups of sugar as there are of juice heat in the oven without discoloring (stir often), then, when the juice boils, add the sugar and let boil a few minutes or until a little will jelly on a cold plate. Cook but a small portion of juice at a time.
Cut apples in quarters without removing skins or cores unless defective; cut plums in halves, and pull grapes and currants from the stems. A little water needs be added to apples, crab apples, quinces and other dry fruit. Avoid the use of water with currants, grapes, etc., let cook until the pulp is softened, then strain without pressure. Press the bag to get the last of the juice and with this make a second quality of jelly. Jelly made of dry fruits will harden after it is set aside in the glasses, and if cooked to the consistency usually desired in currant and similar jellies will be too firm and solid in a few weeks. Equal quantities by weight of barberries and apples make a delicious jelly. Green gooseberries or green plums give a delicately tinted jelly.
 
Continue to: