Busolt allowed. the sun to fall through the six-foot heliometer of the Konigsberg observatory first upon white paper, and then upon a disc of the finest gypsum cast on a mirror. He believes that he has discovered the peculiar color of the , solar spots to be purple, and that they are surrounded by a splendid yellow, and a larger pale yellow halo. The sun itself is said to present a colorless surface which is sprinkled over with purple spots.