This section is from the book "Preserving And Pickling", by Mary M. Wright. Also available from Amazon: Preserving and Pickling: Two Hundred Recipes for Preserves, Jellies, Jams, Marmalades, Pickles, Relishes and Other Good Things.
In making jelly, rhubarb is fine combined with other fruits. Currants and rhubarb boiled together make a delicious jelly. If black currants are used mix half and half; if red currants are used take one part currants and two of rhubarb. Use a pound of sugar to each pint of juice. Make as you would any other jelly. Rhubarb juice and peach juice are good combined in jelly, and will jelly much nicer than either used alone. Use half and half of each and three-fourths of a cup of sugar to each pint of juice. Red raspberries and rhubarb are also nice combined in jelly. Use one part of rhubarb to two of raspberries, and a pound of sugar to each pint of juice.