In 1889 Edward Emerson Barnard found, second hand, here in San Francisco, one of the large Willard lenses used by portrait photographers in the days when photographic plates were still very slow, and began taking pictures of the Milky Way through the transparent air of Mount Hamilton. Small as it was (aperture 6 in., focal length 31 in.), Barnard's new instrument brought a new understanding of the clouds of stars along the Galactic Circle. Photographically efficient, it recorded faint stars in great numbers. Large in field, it embraced whole clouds, instead of only a sample of stars from some part of a cloud. It showed also the vacancies of Herschel and other seemingly starless regions in relation to the star clouds with a contrast beyond the power of the eye. Barnard continued his observations with the much more effi-