249 NEW STARS IN ANDROMEDA AND ORION. 
upon its own peculiarities, I will preface my description 
by a brief account of some of the new stars which have 
been recorded in astronomical annals. For the time 
being astronomy adopts a division into two sections of 
those heavenly bodies which rise and fall in brilliancy. 
Those stars which burst into view, suddenly or gradu- 
ally lose light, and then disappear, or if they do not. 
wholly disappear from telescopic sight, become ex- 
ceedingly faint bodies which show no further indication 
of change,—such are called ‘*‘ temporary stars.’’ Those 
which vary in magnitude, whether regularly or irregu- 
larly, and whether through longer or shorter periods of 
time, are called variables. It at oncesuggests itself that 
temporary stars may be variables whose periods are of 
such enormous durations and whose changes are of such 
a spasmodic character that the centuries covered by 
astronomical records are not numerous enough to pro- 
vide data for their detection. There is a difference be- 
tween the two classes, however, to which I shall return 
later, z.e., a difference in their quality and light as thus 
far revealed by spectrum analysis, and this divergence 
affords a better ground of separation than the definition 
given above. 
The remarkable temporaries of earlier centuries are 
well known to readers of astronomical books ; that dis- 
covered by Hipparchus in 140 4.p., that by Tycho 
Brahe in 1572, and that by Kepler in 1604 holding 
prominent places, because of their superior brilliancy. 
But the temporaries of 1866 and 1876 are of especial 
interest and importance, not because of transcendent 
brightness, but because of the great care with which 
they were observed, and pre-eminently, because they 
were the first new stars to which spectrum analysis was 
applied. On May 12, 1866, a Mr. Birmingham, in 
Ireland, saw a star of the second magnitude in the 
northern crown, which he recognized as a hew appear- 
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