_Great Nebula in Orion_ (M. 42). Visible to the naked eye just below a line connecting β and ζ Orionis, and involving θ Orionis. It exhibits an extremely complicated structure, and many of its irregular branches and condensations may be discerned in small instruments. Sir W. Herschel failed to resolve this object into stars with his 4-foot reflector; but Lord Rosse, in 1844, thought he had effected it with his 6-foot mirror, though the conclusion was premature. The spectroscopic researches of Huggins have shown this nebula to be composed of incandescent gases, so that the stars telescopically observed in it are probably in the foreground and entirely disconnected from the nebulous mass. Effective photographs have been taken of it by Draper, Common, and Roberts. It certainly forms one of the grandest objects in the heavens. The _Planetary_[62] _Nebula_ (M. 97). Discovered by Mechain in 1781. In small telescopes it looks like a rather faint, round mass of nebulosity, somewhat brighter in the middle than at the edges. In Lord Rosse’s telescope it shows many details, including a spiral arrangement and two dark spots in the middle inclosing bright, eye-like condensations. The margin is fringed with protuberances, and from its peculiar aspect this object has been called the “Owl” Nebula. Diameter between 155″ and 160″. It may readily be picked up 2-1/4° S.E. of β Ursæ Majoris. It yields a gaseous spectrum. In Draco at R.A. 17^h 58^m 36^s, Dec. +66° 38′ there is a pretty small, but exceedingly bright planetary nebula. With a low power it looks like a star out of focus, but a high power expands it into a well-defined planetary disk. As observed in Lord Rosse’s 3-ft. reflector on Sept. 17, 1873, this nebula exhibited “a round, well-defined disk of a full blue colour, light very equable, diameter 22″·4, surrounded by an extremely faint nebulosity.” This is an excellent object of its class.