| | α Herculis | W. Herschel, 1795.| | U Ophiuchi | Sawyer, 1881. | | β Lyræ | Goodricke, 1784. | | χ Cygni | Kirch, 1686. | | ζ Aquilæ | Pigott, 1784. | | Y Cygni | Chandler, 1886. | | μ Cephei | Hind, 1848. | | δ Cephei | Goodricke, 1784. | +——————————————+——————————————————-+ _New or Temporary Stars._—These stars (sometimes classed with variable stars) furnish us with rare instances of vast physical changes occurring among sidereal objects, usually so steadfast and endurable. The alternating lustre of certain variable stars represents phenomena of regular recurrence, and is probably to be explained by simple causes; but the sudden outbursts and rapid decline of temporary stars are facts of a more startling character, and need a more exceptional explanation. The first of these objects recorded in history appears to have been seen in Scorpio 134 years before the Christian era, and it suggested to Hipparchus of Rhodes the idea of forming a catalogue of stars, so that in future ages observers might have the means of recognizing new stars or any other changes in the configuration of the heavens. Hipparchus completed his catalogue in 128 B.C.; it contained 1025 stars, and forms one of the most valuable memorials we possess of the labours of the ancient astronomers. Another temporary star is said to have appeared in 130 A.D., but this and several other objects of presumably similar character noticed in later years may just possibly have been comets, and considerable doubt hangs over the descriptions. It will therefore be safest to confine our remarks to more modern and better attested instances of these phenomena[53]:—