New Stars, sometimes called temporary stars, are bodies which suddenly make their appearance in the heavens, rise rapidly to their full brightness, and soon begin to diminish until they can be seen only with a telescope or, perhaps, not at all.  The earliest one of which we have any account is that of 1572, generally known as the Star of Tycho Brahe.  But it is only since the invention of the spectroscope that this class of stars has come to be of especial interest.  The new star in the constellation of Corona Borealis, discovered by Birmingham on May 12, 1866, was examined spectroscopically by Huggins and Miller.  They found that it possessed both a dark line spectrum and a bright line spectrum, differing in this respect from nearly all the other stars.  The next new star was that in the constellation of the Swan, known as Nova Cygni, discovered on Nov. 24, 1876, a red star of the third magnitude.  Two years later it was fainter than the 11th magnitude.  Nova Andromedæ was discovered in August, 1885; and Nova Orionis in December of the same year.  But the star which Anderson at Edinburgh discovered on Jan. 24, 1892, far exceeded all previous new stars in interest, because the power of the spectroscope had been increased in many ways since the previous stars were observed.  For a full account of this star, called Nova Aurigæ, the reader is referred to Scheiner’s Astronomical Spectroscopy, where its interesting spectrum is described in detail.  The next and only other important new star was also discovered by Anderson, this time in the constellation of Perseus, Feb. 22, 1901.  Many theories have been advanced to explain this curious phenomenon; but the one which at present seems most probable is that advanced by Seeliger:  The new star is produced by some dark body rushing into a meteor swarm or a nebula, the impact of small particles being sufficient to bring the dark body to incandescence.