Cut the apricots into wedges. Rinse the limes with hot water, rub dry, peel off the peel in fine strips and squeeze out the juice. Mix both with apricots and preserving sugar in a large saucepan and cover and let steep for 3 - 4 hours. Pluck the thyme leaves, add to the apricot and sugar mixture and bring to the boil, stirring occasionally. Let it boil for about 4 minutes while stirring. Fill the jam to the brim in twist-off glasses rinsed with hot water and close tightly.