Produced by Bryan Ness and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive/American Libraries.) In the original negatives of subjects 10 and 12, there are faint dark rings immediately surrounding some of the stars in the denser parts of the nebulosity. This effect has no doubt been accentuated in the subsequent photographic processes. On the plates of these two subjects in the completed volume, these rings are very distinct and give rise to a suspicion that the effect has been enhanced by the engraver. A critical examination of the prints seems to confirm this view. In the original proofs t…
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