slice limes thinly, remove and discard seeds. combine limes in bowl with water, cover, stand overnight.
next day, transfer mixture to large boiler, bring to boil, reduce heat, simmer, covered, about 1 hour or until rind is tender.
measure fruit mixture, allow 1 cup sugar to each 1 cup fruit mixture. return fruit mixture and sugar to boiler (mixture should not be more than 5 cm deep at this stage), stir without boiling over high heat until sugar is dissolved.
bring to the boil, boil rapidly, uncovered, without stirring, about 15 minutes or til a tsp of mixture gels when tested on a cold saucer.
remove boiler from heat, add ginger, stand 10 min. before pouring into hot sterilized jars; seal when cold.
makes about 8 cups